Critical Updates on Canine and Feline Health Sponsored by: ® ® Critical Updates on Canine & Feline Health From thought leaders in our profession The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs 3 Stanley L. Marks, BVSc, PhD, DACVIM (Internal Medicine, Oncology), DACVN Vomiting Cat Cases: You Can Figure Them Out 11 Debra L. Zoran, DVM, PhD, DACVIM Nutrition for Senior Dogs: New Tricks for Feeding Old Dogs 20 Julie A Churchill, DVM, PhD, DACVN Pet Food Myth Busters: Answering Common Questions Owners Ask About Pet Food 26 Lisa M. Freeman, DVM, PhD, DACVN Sponsored by: ® ® 2015 NAVC/WVC Symposia Proceedings The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs Stanley L. Marks, BVSc, PhD, DACVIM (Internal Medicine, Oncology), DACVN Professor of Small Animal Medicine University of California, Davis School of Veterinary Medicine Davis, California D iarrhea is generally regarded as the most consistent clinical sign of intestinal disease in dogs and cats and is one of the most frustrating disorders for many veterinarians to diagnose and manage. Incomplete resolution of the problem can result in frustration and dissatisfaction for the owner and potential suffering for the animal. Antibiotics are commonly administered injudiciously to diarrheic animals, with resolution of clinical signs often wrongly attributed to eradication of a putative infectious pathogen. Chronic diarrhea is persistent or relapsing over a period of 3 to 4 weeks or longer. In contrast to acute diarrhea that is often self-limiting and does not typically require a comprehensive workup, chronic cases warrant a step-by-step approach to obtain a diagnosis and formulate an optimal therapeutic plan. The exception to this rule is in dogs with acute hemorrhagic diarrhea syndrome that can be associated with a number of infectious and non- 2 The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs infectious causes and typically lasts less than 1 week. The history and physical examination are paramount for determining whether the diarrhea is caused by primary disease of the gastrointestinal (GI) tract or is secondary to extraintestinal diseases such as pancreatic insufficiency or Addison’s disease (Table 1). The need for performing fecal screening for putative enteropathogens, resting cortisol for Addison’s disease, tests for pancreatitis [canine pancreas specific lipase (Spec cPL, IDEXX Laboratories) and ultrasound], or abdominal radiographs for GI foreign bodies should be based upon the patient’s signalment, history (including vaccination history), and physical examination findings. The categorization of diarrhea into small bowel or large bowel in origin is helpful for prioritizing certain differentials (Table 1) and for determining which segment of bowel to biopsy if indicated. Caution is warranted in this over-simplistic anatomic differentiation of the affected segment of bowel because animals manifesting clinical signs of colitis often have concurrent disease in the small bowel and vice versa. In addition, most veterinary gastroenterologists prefer to biopsy the small and large intestine when feasible to maximize diagnostic yield of the procedure. Failure to consider the role of the diet or dietary supplements in precipitating or alleviating the GI disorder can result in delayed diagnosis or improper dietary recommendations. The history should also focus on the duration of the diarrhea, the appearance of the feces (color, volume, mucus, presence of fresh blood), worming and vaccination history, defecation frequency, aggravating or alleviating factors, and defecation urgency. DIAGNOSTIC TESTS & PROCEDURES Fecal Examination for Parasites The diagnosis of GI parasites in dogs and cats is an integral component of small ani- mal practice. The following guidelines can help veterinarians maximize the diagnostic yield of fecal examinations for parasites. 1. Fresh fecal specimens should be refrigerated to facilitate preservation of eggs, oocysts, and cysts if immediate fecal flotation cannot be performed following collection. 2. Centrifugation fecal flotation is vastly superior to standing (gravitational) flotation.1,2 The type of flotation solution and its specific gravity does affect the diagnostic yield. Aqueous zinc sulfate (ZnSO4) with a specific gravity of 1.18 to TABLE 1 Common Differentials for Chronic Diarrhea in Dogs Small Intestine Large Intestine Inflammatory bowel disease X X Infiltrative neoplasia: lymphoma, mast cell tumor, carcinoma X X Endoparasites: helminths, Giardia, Cystoisospora, Cryptosporidium X X Food-responsive enteropathy X X Bacterial, viral, and fungal enteropathogens: Campylobacter, Salmonella, Histoplasma spp, Pythium X X Intestinal obstruction secondary to strictures, intussusception X X Ileus X Organism Primary GI Disorders Extragastrointestinal Disorders Addison’s disease X Hyperthyroidism X Pancreatitis X Exocrine pancreatic insufficiency X Pancreatic neoplasia X Liver failure: uncommon cause of diarrhea X Uremia X Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings X X 3 Diagnostic Approach to Dogs with Chronic Enteropathies History • Detailed and accurate, including comprehensive dietary history Physical examination Minimum database • CBC • Serum biochemistry panel • Urinalysis • Fecal centrifugation flotation and direct wet-prep Additional fecal tests that may be warranted • Fecal Giardia ELISA or IFA test for Giardia and Cryptosporidium: Fecal ELISA for Giardia should be used only as a screening test to diagnose infection before initiating anthelmintic therapy • Fecal enteric panel (culture and toxin assays) or fecal PCR panel: Reserve for animals developing diarrhea after boarding or show attendance, cats and dogs with acute onset of bloody diarrhea in association with evidence of sepsis or diarrhea, outbreaks occurring in more than one pet in a household, and zoonotic concerns (Campylobacter, Salmonella) in diarrheic pets in contact with immunocompromised humans • Abdominal radiography: Relatively low-yield procedure in animals with chronic diarrhea but is indicated in animals with suspected partial obstructions from foreign body/ intussusception/mass or gas distention/torsion of the GI tract Dietary trial • Elimination diet or hydrolyzed diet: Selected based on the animal’s dietary history; recommend dietary trial to help rule out food-responsive enteropathy before procuring intestinal biopsies in stable animals (no evidence of hypoalbuminemia, hypocobalaminemia, fever, melena) • High-fiber diet: Can be tried in animals with colitis if there is no response to an elimination diet trial; response should be recognized within 7 to 10 days of initiating the trial diet Antibiotic trial • Antibiotic-responsive diarrhea (ARD) affects large and giant breed dogs predominantly and is associated with signs of enteritis or colitis • Tylosin (5–10 mg/kg q24h PO) is the drug of choice for dogs with suspected ARD and is administered prior to procurement of intestinal biopsies in dogs failing to show an adequate response to dietary therapy Empirical deworming with broad-spectrum anthelmintic Tests of assimilation • Serum cobalamin and folate: Assessment of absorption in the ileum and jejunum, respectively • Trypsin-like immunoreactivity (cTLI): Diagnosis of exocrine pancreatic insufficiency Imaging • Abdominal ultrasonography: Evaluation of the pancreas; intestinal wall thickening, layering of the wall, echogenicity of layers; mesenteric lymph nodes; liver; spleen; kidneys; presence of peritoneal fluid Miscellaneous tests or procedures • Spec cPL: Pancreatitis • Thyroxine (T4) in dogs with polyphagia, weight loss and diarrhea and no evidence of exocrine pancreatic insufficiency or chronic enteropathy • Rectal scraping: pythiosis, histoplasmosis, protothecosis, and eosinophilic colitis or proctitis GI biopsies • Endoscopy: Recommended to procure ileal biopsies particularly when serum cobalamin concentration is abnormally decreased • Full-thickness biopsy specimens: Laparotomy versus laparoscopy 1.2 has been widely recommended because it will float cysts, oocysts, and most helminth eggs with a minimum of distortion and fecal debris. Other acceptable solutions include Sheather’s sugar and sodium nitrate. 3. Giardia and Cryptosporidium immunoassays increase the diagnostic yield of the fecal exam when performed in parallel with centrifugation flotation. Enzymelinked immunosorbent assays (ELISAs) detect Giardia cyst-wall protein 1 (GCWP 1) and are generally easy to perform and interpret. The SNAP Giardia Test (IDEXX 4 Laboratories) is a rapid in-house enzyme immunoassay that can be performed on fresh or previously frozen feces or samples stored at 2°C to 7°C for up to 7 days.3 ELISAs should not be used to assess response to therapy in animals that have completed a recent course of anthelmintics because animals can remain positive for Giardia spp on the SNAP ELISA for several weeks following successful eradication of the parasite. A second type of immunoassay called direct immunofluorescence (DIF)4 has the added benefit of detecting both Giardia and Cryptosporidium in feces, but The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs mans. Dogs have mainly assemblages C and D; cats have assemblages A1 and F; humans have assemblages A2 and B. Assemblages can be determined via PCR5 to determine the likelihood of zoonotic transmission from animals to humans, although the risk for transmission of Giardia spp to humans is generally very low. Figure 1. Positive direct-immunofluorescence (DIF) assay showing the smaller round apple-green fluorescent oocysts of Cryptosporidium and the larger oval-shaped cysts of Giardia in a puppy with diarrhea. Magnification 400X Figure 2. Abundant hairpin-shaped gram-positive endospores consistent with Clostridium perfringens in a healthy nondiarrheic puppy that presented for routine vaccination. Magnification 400X requires a fluorescent microscope. A positive result is indicated by apple green fluorescence of the cyst (Giardia) or oocyst (Cryptosporidium) (Figure 1). Morphologic identification is necessary for this technique. 4. Polymerase chain reaction (PCR)-based tests for Giardia and Cryptosporidium spp are commercially available although the author recommends fecal flotation and DIF or ELISA testing for the routine diagnosis of both organisms. An exception is the use of PCR for determining Giardia “assemblages” to assess the infectivity potential of the isolate for animals and hu- Fecal Examination for Bacteria 1. PCR and bacterial culture/toxin imunoassays are low-yield diagnostic procedures in animals with diarrhea if the tests are performed injudiciously.6 If bacterial enteritis or enterocolitis is suspected, the feces should be cultured or PCR should be performed for specific enteropathogens, such as Salmonella spp or Campylobacter jejuni. Fecal PCR is superior to culture for the diagnosis of Campylobacter spp, and facilitates the rapid diagnosis of multiple species of Campylobacter.6,7 2. Fecal cytology on stained fecal smears is commonly performed to identify the underlying cause of diarrhea by looking for spiral-shaped bacteria (Campylobacter-like organisms), white blood cells, and fecal endospores associated with Clostridium perfringens. Unfortunately, the detection of increased fecal endospores is of no clinical diagnostic utility8,9 (Figure 2) and the overall value of stained fecal smears is extremely limited. Detection of spiral-shaped organisms resembling Campylobacter spp is insufficient when used alone to diagnosis Campylobacter-associated diarrhea. Veterinarians should be cognizant of the fact that most bacterial enteropathogens are associated with self-limiting diarrhea, and injudicious administration of antimicrobials could be more harmful than beneficial. Supportive therapy and appropriate hygiene control should be considered in all cats with suspected or confirmed bacteria-associated diarrhea. An- Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings Most bacterial enteropathogens are associated with self-limiting diarrhea. … Antimicrobials should be administered only to animals manifesting systemic signs of illness. 5 timicrobials should be administered only to animals manifesting systemic signs of illness. Measurement of serum cobalamin and folate concentrations provides insight into the functional integrity of the ileum and jejunum, respectively. Interpretation of Hematology & Serum Biochemistry Panels The complete blood count (CBC) may reveal peripheral eosinophilia secondary to endoparasitism, eosinophilic inflammatory bowel disease (IBD), Addison’s, abdominal mast cell neoplasia, or lymphoma (paraneoplastic phenomenon). Anemia may result from enteric blood loss or from depressed erythropoiesis caused by systemic disease or chronic inflammation. The serum biochemistry panel can provide additional information pertaining to the likely cause of diarrhea and help rule out extra-GI causes of diarrhea (renal disease, hepatic insufficiency). Protein-losing enteropathies represent a syndrome of intestinal disorders (severe IBD, lymphoma, intestinal ulceration) that typically manifest with abnormal loss of serum proteins across an inflamed or abnormally permeable intestinal mucosal barrier. Hypocholesterolemia can be seen secondary to malabsorption. A discordant BUN:creatinine ratio results from dehydration (prerenal azotemia), GI bleeding, high-protein meal, and cachexia. Elevated liver enzymes should be interpreted cautiously in dogs with intestinal disease or pancreatitis because drainage of bacteria or endotoxin via the portal circulation can precipitate a “reactive hepatopathy.” Tests of Intestinal Function Measurement of serum cobalamin and folate concentrations provides insight into the functional integrity of the ileum and jejunum, respectively. Low serum cobalamin has been described in dogs in association with a variety of GI diseases, including IBD, intestinal lymphoma, and lymphangiectasia. Mucosal repair is impeded when cobalamin is deficient and its absorption impaired. Dogs that are deficient in cobalamin are typically administered cyanocobalamin subcu- 6 taneously (SC) on a weekly basis at 250 to 1500 µg/dose (depending on the animal’s weight) SC for 6 weeks, followed by dosing every 2 to 3 weeks for the indefinite future. Abdominal Imaging Survey abdominal radiography is a relatively low-yield procedure in most dogs with chronic diarrhea but is indicated in animals suspected of having partial obstructions caused by foreign bodies, intussusceptions, or masses, or in those with gas distention or displacement of the stomach or bowel. Abdominal ultrasonography is complementary to survey abdominal radiography; it is more sensitive for detection of abdominal masses, intestinal mural thickening, intussusceptions, “tiger-stripe” lines in the mucosa (Figure 3), and mesenteric lymphadenopathy.10 In addition, ultrasound-guided percutaneous biopsy or aspiration of masses is an effective diagnostic procedure. Contrast radiography and fluoroscopy are occasionally indicated for identifying partial obstructions and intestinal motility disorders, respectively. Endoscopy & Biopsy Pitfalls & Recommendations Endoscopy is a valuable procedure for diag- Figure 3. Ultrasound image of a segment of duodenum from a 4-year-old castrated male toy poodle with severe intestinal lymphangiectasia. Note the hyperechoic lines (“tiger-stripes”) extending from the lumen of the duodenum to the submucosal layer. This finding is highly supportive of intestinal lymphangiectasia in dogs. The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs Figure 4. Endoscopic view of the duodenum of a 5-year-old castrated male Rottweiler with histopathologically confirmed IBD. The mucosa is erythematous and granular in appearance. nosis of intestinal mucosal disorders associated with morphologic changes, but it does not differentiate intestinal motility disorders, secretory diarrheas, or brush-border enzyme defects. In addition, lesions of the intestinal submucosa and muscularis propria layers of bowel can easily be missed, and endoscopy is limited by the working length of the scope, precluding examination of the jejunum. With the support of the World Small Animal Veterinary Association, the Gastrointestinal Standardization Group has proposed a standardized histologic evaluation system that can be applied to all companion animal gastroenterologic disorders to minimize interobserver observation among pathologists.11 COMMON CHRONIC ENTEROPATHIES IN DOGS Food-Responsive Enteropathy Food-responsive enteropathy is a common cause of chronic diarrhea in dogs and the disorder is associated with a relatively high response rate (45%–60%) to the feeding of elimination diets containing novel, single sources of protein (intact or hydrolyzed).1214 Most dogs with a food-responsive enteropathy show a relatively rapid resolution of clinical signs within 3 to 4 days following implementation of dietary therapy. In a re- port of dogs with lymphocytic–plasmacytic colitis, clinical signs resolved in all 13 cases with introduction of an elimination diet, and of 11 dogs rechallenged with their original diet, 9 relapsed.12 The theoretical basis for protein hydrolysate diets is that reduction in immunogenic epitopes being presented to the mucosal immune system during dysregulation will increase the potential for resolution. Thus, the argument for the use of a hydrolysate diet is independent of whether a diet-specific immunologic response is suspected. Experience with protein hydrolysate diets is increasing and anecdotally they appear to be effective adjuncts to pharmacologic therapy or even as the sole therapy. Clinical resolution with histologic improvement has been reported in 4 of 6 dogs with refractory IBD when treated with a hydrolyzed soy-protein diet alone.13 In addition, feeding a hydrolyzed diet to 18 dogs with chronic small bowel enteropathy was shown to be superior to feeding a highly digestible control diet for long-term management.14 It is possible, however, that nutritional factors other than protein hydrolysis were responsible for the improvement. These factors could include dietary digestibility, correction of vitamin or mineral deficiencies, reduced fat content, lowered n-6:n-3 fatty acid ratio, and possible immunomodulatory effect of soy isoflavones within the hydrolyzed diets. Antibiotic-Responsive Diarrhea (ARD) or Tylosin-Responsive Diarrhea ARD is essentially a canine phenomenon and is seen more commonly in large and giant-breed dogs. German shepherd dogs appear to be particularly predisposed to ARD that is characterized by small bowel or large bowel diarrhea in the absence of an underlying cause.15 These dogs do not appear to have bacterial overgrowth (SIBO), but rather a dysbiosis of their microbiota. ARD is typically managed with tylosin at 5 to 10 Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings The argument for the use of a hydrolysate diet is independent of whether a diet-specific immunologic response is suspected. 7 mg/kg every 24 hours for 3 to 4 weeks; however, many dogs may need to be treated for 4 weeks or longer. Many dogs with ARD have failed to respond to metronidazole administration. Administration of probiotics to dogs with IBD represents a novel alternative therapeutic modality that warrants further investigation. 8 Inflammatory Bowel Disease Diagnosis of IBD is based on compatible clinical signs (chronic diarrhea, vomiting, weight loss, with or without borborygmus and flatulence) and exclusion of metabolic, infectious, neoplastic, and obstructive disorders of the gut. Biopsies must show histologic evidence of moderate to marked infiltration of the GI mucosa by inflammatory cells (predominantly lymphocytes and plasma cells) and changes in mucosal architecture for a diagnosis of IBD to be rendered (Figure 4). Management of canine IBD includes elimination or hypoallergenic diets, antimicrobials (tylosin, metronidazole) and/or immunomodulatory drugs (prednisolone, budesonide, chlorambucil), and cyanocobalamin supplementation. Administration of probiotics to dogs with IBD represents a novel alternative therapeutic modality that warrants further investigation. Probiotics have also been utilized to facilitate eradication of intestinal parasites. A recent study documented the ability of the probiotic organism Enterococcus faecium SF68 (FortiFlora, Nestlé Purina) to antagonize Giardia intestinalis infection in mice.16 Oral feeding of E faecium strain SF68 starting 7 days before inoculation with Giardia trophozoites significantly increased the production of specific anti-Giardia intestinal IgA and blood IgG and increased CD4(+) T cells, with associated diminution in the number of active trophozoites in the small intestine and decreased shedding of fecal Giardia antigens (GSA65 protein). Probiotic administration of VSL #3 strain to dogs with IBD has also been associated with clinical improvement and enhancement of regulatory T-cell markers [FoxP3+ cells and transforming growth factor-β (TGF-β)+ cells] compared with a placebo-control group.17 Intestinal Lymphangiectasia Protein-losing enteropathy (PLE) is a syndrome caused by a variety of gastrointestinal diseases causing the enteric loss of albumin and globulin. Intestinal inflammation, infiltration, ulceration, blood loss, and primary or secondary lymphangiectasia (Figure 5) are well-documented causes of PLE. If left untreated, the final outcome of PLE is panhypoproteinemia with decreased intravascular oncotic pressure and the development of abdominal and pleural effusion (Figure 6), peripheral edema, and Figure 5. Segment of jejunum from a Yorkshire terrier showing marked erythema, lipogranulomas, and dilated lacteals visible on the serosal surface of the bowel during an exploratory laparotomy. Figure 6. A 3-year-old spayed female golden retriever with severe cachexia and abdominal distention secondary to ascites associated with intestinal lymphangiectasia. The Mysteries of the GI Tract: Demystifying Chronic Diarrhea in Dogs death. An important sequel to PLE includes thromboembolic disease secondary to the loss of antithrombin. The signalment of the animal is important as certain breeds such as the Yorkshire terrier, soft-coated Wheaten terrier, Norwegian lundehund, and Basenji are predisposed to PLE. Additional abnormalities found on the serum biochemistry profile in association with PLE include hypocholesterolemia (secondary to malabsorption) and hypocalcemia. The multifactorial causes include hypoalbuminemia (affects total calcium), decreased absorption of vitamin D, and malabsorption of magnesium. Measurement of total and ionized serum magnesium is recommended in animals with GI disease and hypocalcemia. Moderate dietary fat restriction is one of the most important aspects in the management of dogs with intestinal lymphangiectasia. Diets that are highly digestible and contain less than 25% fat calories are most commonly recommended. The author recommends the feeding of a premium commercial-based diet if possible; however, there are a small number of dogs with severe lymphangiectasia that will need further fat restriction than that provided in commercial diets, and home-cooked diets are warranted. These home-cooked diets should be made up by a veterinary nutritionist to ensure that the diets are complete and balanced. Dogs with concurrent IBD and lymphangiectasia are more challenging to manage from a dietary perspective because these animals need a novel, select protein source or hydrolyzed diet that is also moderately fat restricted, such as Purina Veterinary Diets HA Hypoallergenic Canine Formula (Nestlé Purina). The current vegetarian formulation of HA contains a soy-protein hydrolysate and contains 24% fat calories, representing a viable dietary option for dogs with lymphangiectasia with or without concurrent IBD. References 1. Comparison of common fecal flotation techniques for the recovery of parasite eggs and oocysts. Dryden MW, Payne PA, Ridley R, et al. Vet Ther 6:15-28, 2005. 2. Accurate diagnosis of Giardia spp. and proper examination procedures. Dryden MW, Payne PA, Smith V. Vet Ther 7:4-14, 2006. 3. Prevalence of Giardia in symptomatic dogs and cats throughout the United States as determined by the IDEXX SNAP Giardia test. Carlin EP, Bowman DD, Scarlett JM, et al. Vet Ther 3:199-206, 2006. 4. Evaluation of immunofluorescence microscopy and enzyme-linked immunosorbent assay in detection of Cryptosporidium and Giardia infections in asymptomatic dogs. Rimhanen-Finne R, Enemark HL, Kolehmainen J, et al. Vet Parasitol 145:345-348, 2007. 5. Comparisons of mammalian Giardia duodenalis assemblages based on the β-giardin, glutamate dehydrogenase and triose phosphate isomerase genes. Scorza AV, Ballweber LR, Tangtrongsup S, et al. Vet Parasitol 189:182-188, 2012. 6. Enteropathogenic bacteria in dogs and cats: Diagnosis, epidemiology, treatment, and control. Marks SL, Rankin SC, Byrne BA, Weese JS. J Vet Intern Med 25:1195-1208, 2011. 7. Prevalence of selected bacterial and parasitic agents in feces from diarrheic and healthy control cats from Northern California. Queen EV, Marks SL, Farver TB. J Vet Intern Med 26:54-60, 2012. 8. Genotypic and phenotypic characterization of Clostridium perfringens and Clostridium difficile in diarrheic and healthy dogs. Marks SL, Kather EJ, Kass PH, Melli AC. J Vet Intern Med 16:533-540, 2002. 9. Evaluation of methods to diagnose Clostridium perfringens-associated diarrhea in dogs. Marks SL, Melli AC, Kass PH, et al. JAVMA 214:357-360, 1999. 10. Ultrasonographic evaluation of gastrointestinal diseases in small animals. Penninck DG, Nyland TG, Kerr LY, et al. Vet Radiol 31:134-141, 1990. 11. Interobserver variation among histopathologic evaluations of intestinal tissues from dogs and cats. Willard MD, Jergens AE, Duncan RB, et al. JAVMA 220:1177-1182, 2002. 12. Nutritional management of idiopathic chronic colitis in the dog. Nelson RW, Stookey LJ, Kazacos E. J Vet Intern Med 2:133-137, 1988. 13. Dietary trial using a commercial hypoallergenic diet containing hydrolyzed protein for dogs with inflammatory bowel disease. Marks SL, Laflamme D, McCandlish AP. Vet Ther 3:109-118, 2002. 14. A randomized, open-label, positively-controlled field trial of a hydrolyzed protein diet in dogs with chronic small bowel enteropathy. Mandigers PJ, Biourge V, van den Ingh TS, et al. J Vet Intern Med 24:1350-1357, 2010. 15. Tylosin-responsive chronic diarrhea in dogs. Westermarck E, Skrzypczak T, Harmoinen J, et al. J Vet Intern Med 19:177-186, 2005. 16. Enterococcus faecium SF68 enhances the immune response to Giardia intestinalis in mice. Benjacoub J, Pérez PF, Rochat F, et al. J Nutr 135(5):1171-1176, 2005. 17. Comparison of microbiological, histological, and immunomodulatory parameters in response to treatment with either combination therapy with prednisone and metronidazole or probiotic VSL#3 strains in dogs with idiopathic inflammatory bowel disease. Rossi G, Pengo G, Caldin M, et al. PLoS One 9:e94699, 2015. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings Moderate dietary fat restriction is one of the most important aspects in the management of dogs with intestinal lymphangiectasia. 9 Vomiting Cat Cases: You Can Figure Them Out V Debra L. Zoran, DVM, PhD, DACVIM College of Veterinary Medicine Texas A&M University College Station, Texas omiting, one of the most common reasons for cats to be presented for evaluation, is often considered to be “normal.” There is some truth to the idea that cats vomit more readily from eating too much or too fast; eating foods that are unusual, especially food that contains toxins; or grooming (vomiting hair). However, such vomiting should not be routine. If it is, there is often an underlying cause that needs to be addressed. Adult and senior cats have different causes of vomiting than kittens do, but there are similarities in the approach to diagnosis of vomiting in cats of any age. To simplify the process, it is sometimes helpful to separate the multitude of causes of vomiting into two more distinct groups: vomiting caused by diseases or disorders of the gastrointestinal (GI) tract itself or vomiting due to systemic or non-GI diseases and disorders that trigger either peripheral or central neural pathways (Table 1). Vomiting caused by primary GI diseases includes such differentials as infectious, inflammatory, parasitic, anatomic 10 Vomiting Cat Cases: You Can Figure Them Out (obstructive, trichobezoars), neoplastic (alimentary lymphoma), and drug-related or food-related (hypersensitivity, intolerance disorders).1-3 Cats that are vomiting due to extraGI diseases may have a myriad of different systemic problems, but endocrinopathies (eg, hyperthyroidism), metabolic diseases (eg, renal or liver failure), inflammatory diseases of the liver or pancreas, cardiovascular diseases (eg, heartworm disease), central nervous system (CNS) disorders (eg, vestibular or inflammatory CNS diseases), and neoplasia (eg, mast cell tumors, other cancers affecting visceral organs outside the GI tract) are the most common.3-6 This wide spectrum of potential causes of vomiting in cats increases the difficulty of making a definitive diagnosis. Nevertheless, it is important to carefully consider each of the potential differentials to prevent the problem from progressing to create further problems. This article provides an overview of the process of making a diagnosis of some of the more common causes of vomiting in cats and discusses the best approaches to their treatment. Because it is an important factor, the role of diet in both diagnosis and treatment of vomiting is also discussed. Primary Gastrointestinal Disease The GI tract should always be carefully evaluated in a cat that is vomiting; however, vomiting is not pathognomonic for gastric or intestinal disease. Furthermore, while it is rare for laboratory evaluation (ie, hemogram, serum biochemistry panel, urinalysis) to provide the definitive diagnosis for primary GI disease, initial evaluation of the vomiting cat should include a minimum database of routine blood analysis and, if appropriate, thyroid testing, GI function testing, and viral serology––particularly in adult or senior cats with chronic (>3 weeks) vomiting. It is important to note that these tests may not reveal the primary problem but are necessary to determine basic physiologic sta- TABLE 1 Approach to Diagnosis of Vomiting Primary GI Causes Extra-GI Causes • Gastric parasitic or infectious disease • Gastric or intestinal neoplasia • Pancreatic disease (pancreatitis or exocrine pancreatic insufficiency) • Cholangitis or hepatic disease (hepatic lipidosis, intrahepatic cholestasis, cholesterolemia, infection) • Gastric ulcers or erosions • Gastric motility disturbances • Gastric outflow obstruction • IBD • Dietary hypersensitivity (allergy or intolerance) • Intestinal dysbiosis • Mechanical or obstructive disease • Endocrinopathies (eg, hyperthyroidism, diabetic ketoacidosis) • Systemic infectious disease (eg, toxoplasmosis, feline infectious peritonitis, fungal) • Neoplasia (eg, lymphosarcoma, especially in abdomen or brain, mast cell tumor) • Heartworm/parasitic lung disease • Acute or chronic renal disease • Diseases of CNS, causing nausea CNS = central nervous system, GI = gastrointestinal, IBD = inflammatory bowel disease tus (ie, electrolyte, acid–base, fluid needs) and rule out other systemic diseases. GI function testing includes that of feline pancreatic lipase immunoreactivity, feline trypsin-like immunoreactivity, cobalamin, and folate. These tests are important for assessing pancreatic function but also give an indication of small intestinal health, as cobalamin and folate are important indicators of intestinal dysbiosis or disease. If primary GI disease is considered likely based on physical examination, history, or normal laboratory results, then imaging (eg, radiographs, abdominal ultrasound) is indicated either to make a definitive diagnosis or identify abnormalities that require further diagnostic steps. Radiographs and abdominal ultrasound have different purposes based on the likely differentials. If a foreign body is suspected (eg, young cat/kitten), a radiograph is reasonable. On the other hand, if diseases of the bowel wall or abdominal organs requiring ability to measure layers or size are suspected (eg, inflammatory bowel disease [adult cat]), then abdominal ultrasonography is the best approach. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings If primary GI disease is considered likely, then imaging is indicated either to make a definitive diagnosis or identify abnormalities that require further diagnostic steps. 11 In some cats, more invasive tests (eg, gastroduodenoscopy, exploratory laparotomy) may be required to obtain biopsy material or remove the problem (obstruction). The decision to pursue endoscopy versus exploratory surgery depends on availability of necessary equipment and expertise as well as the likelihood that endoscopy can be a useful diagnostic or treatment tool (eg, an endoscope will not reach the mid or distal jejunum). The diagnosis of both food hypersensitivity and intolerance is based on removing the offending substance from the diet. 12 Gastric Disease Among gastric diseases to consider as causes of vomiting are parasitic infestation (eg, with Physaloptera or Ollanus spp), bacterial infections (eg, with Helicobacter spp), neoplastic diseases (eg, lymphoma, adenocarcinoma, leiomyosarcoma), inflammatory diseases (eg, ulcers, inflammatory bowel disease [IBD]), obstructive disorders (eg, hairballs, foreign bodies, masses), and diet-related causes (ie, intolerance, hypersensitivity). Specific diagnosis of individual causes may require additional procedures (eg, histopathologic evidence of spiral organisms deep in gastric glands associated with gastritis) to rule them in or out. Small Intestinal Disease Small intestinal disease in cats is a common cause of vomiting associated with the prevalence of inflammatory disease; however, true idiopathic IBD must be distinguished from the simple presence of inflammatory infiltrates in the small bowel, as a variety of dietary, infectious, and parasitic agents can cause either inflammation in the small bowel or dysbiosis, the latter of which causes inflammation. Dietary sensitivity and intolerance are also important causes of vomiting in cats and should trigger appropriate dietary trials to rule them out. This process may be easier said than done, as finding a commercially available food without the offending substance (intolerance) or antigen (hypersensi- tivity) and that the cat will readily consume is a challenge. In most cases of small intestinal disease affecting the intestinal wall, with the exception of adverse reactions to food, obtaining a definitive diagnosis will require biopsy––either via endoscopy or exploratory surgery. Adverse Reactions/Sensitivity to Food Food intolerance, food allergy (hypersensitivity), food poisoning, food idiosyncrasy, and pharmacologic reactions to foods all fall under the category of adverse reactions to food.7 Discussion here is limited to food intolerance and food hypersensitivity (allergy). Food intolerance, a nonimmunologic, abnormal physiologic response to a food, nutrient, or food additive, is the most common cause of food sensitivity in cats. Food allergy, or hypersensitivity, is characterized by adverse reactions to a food or food additive (typically protein) with a proven immunologic basis. Both allergy to and intolerance of food can result in vomiting, diarrhea, or a combination of signs, depending on the effects: food allergy is more commonly associated with vomiting and dermatologic signs, whereas intolerances of food can present with vomiting or diarrhea but do not produce dermatologic signs. Dietary Elimination Trial The diagnosis of both food hypersensitivity and intolerance is based on removing the offending substance from the diet. The major difference between the diagnostic processes of these two types of adverse food reactions is the length of time on the diet that is required to achieve a response and the need to identify a novel protein source. Cats with food hypersensitivity require 8 to 12 weeks on a novel antigen (eg, novel protein or hydrolyzed protein) elimination diet before an improvement will be seen. Alternatively, in cats with food intolerance, resolution of signs Vomiting Cat Cases: You Can Figure Them Out usually occurs within days (7–14 days is typical) of a diet change in which the offending substance is removed, unless other factors influence the response. A variety of commercially available and homemade elimination formulations can be used, as can those using hydrolyzed proteins. Many different brands fall under the category of “highly digestible,” "sensitive," and "novel," but the key is to remember that they are not all alike. Thus, when one product from this category is not accepted by the cat, is ineffective, or seems to make the problem worse, you cannot assume that all products in this category will fail. Highly digestible products from different pet food manufacturers have a variety of formulations (Table 2), including different protein and carbohydrate sources, different levels of fat, and various additives designed to promote intestinal health (eg, fructooligosaccharides, maltooligosaccharides, omega-3 fatty acids, antioxidant vitamins, soluble fiber). The same is true for hydrolyzed food products. If one type of highly digestible food has been fed for at least 2 weeks with minimal response, it is entirely reasonable to try either another comparable product from a different source or an entirely different dietary strategy (eg, high protein/low carbohydrate, novel antigen, hydrolyzed protein). Thus, a dietary trial consisting of novel meat-source proteins or hydrolyzed foods may not be adequate to remove the offending items from the diet. For example, if the problem is being created by presence or type of carbohydrate in the food, feeding a formulation high in protein (>40% metabolizable energy [ME]) and low in carbohydrates (<10% ME) that is highly digestible (>85% digestibility of protein) will resolve the problem. In some cats, however, the only way to remove the source and confirm this problem is by feeding a homemade food that consists of a meat source (eg, cooked chicken thigh with the fat included) and a vitamin/mineral supplement but no added carbohydrate or other TABLE 2 Dietary Protein Levels & Protein Sources in Selected Highly Digestible Diets for Cats Feline Food (dry) Protein (% DM / Source) Purina Veterinary Diets Feline Formula EN 56% / soy protein isolate Hill’s Prescription Diet i/d Feline 40% / chicken meal IAMS Veterinary Formula Intestinal Plus Low-Residue 32% / chicken by product meal Royal Canin Veterinary Diet Feline Gastrointestinal High Energy HE 30% / chicken meal DM = dry matter ingredients. This diet eliminates carbohydrates and all other commercial food additives and can be fed for up to 2 to 3 weeks, but a complete and balanced food should be formulated by a nutritionist if it must be fed longer. The key feature that separates food intolerance from an allergy is that once the offending agent is removed from the diet, the vomiting (or other GI signs) will resolve quickly. Another key point is that in dietary intolerance the offending substance may be difficult to identify using typical commercial foods, thus a food trial using a homemade diet can be quite helpful. The key point is that dietary management is a process of trial and error. No single diet or diet family will benefit all cats in all situations. Inflammatory or ImmuneMediated Causes of Vomiting IBD, a commonly diagnosed condition of adult cats, is likely due to multiple causes but ultimately culminates from a combination of genetic susceptibility, intestinal microbial dysbiosis, and persistent inflammation of the gut wall, resulting in signs of vomiting, diarrhea, weight loss, or combinations of all three.8 Idiopathic IBD is characterized by persistent clinical signs of GI disease occurring with histologic evidence of mucosal inflammation and structural changes of the villous epithelium without an identifiable or correctable cause (eg, food). Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings A dietary trial consisting of novel meat-source proteins or hydrolyzed foods may not be adequate to remove the offending items from the diet. 13 Studies of probiotic therapy in cats have primarily focused on the use of Fortiflora (Purina) in a shelter environment among kittens or young cats with parasitic diseases (giardiasis, cryptosporidiosis, etc) or stressinduced diarrhea. A number of possible causes of intestinal inflammation must be considered in the diagnostic process, and all should be investigated thoroughly or therapeutic trials instituted prior to settling on the diagnosis of idiopathic IBD––a disease requiring long-term therapy with immunosuppressive drugs. In particular, appropriate food trials are an extremely important component of both diagnosis and therapy of cats with suspected IBD (or GI disease in general). In addition, the diagnostic plan for a cat with chronic vomiting should include assessment of thyroid and feline leukemia virus/feline immunodeficiency virus (FeLV/FIV) status as well as intestinal vitamin (cobalamin/folate) status. Serum cobalamin levels in cats commonly decrease with chronic pancreatitis or severe bowel disease; in cats with hypocobalaminemia, inappetence or vomiting will not resolve until replacement therapy has been instituted.9 Cobalamin therapy (250 g/cat SC weekly for 6 weeks, then once every other week) in some cats may be lifelong, while in others once the clinical disease resolves the supplementation can be discontinued. In addition, radiography and ultrasonography are important in detecting the presence of infiltrative diseases, such as feline infectious peritonitis, granulomas, histoplasmosis, or lymphosarcoma. Ultrasonography has been particularly helpful in identifying intestinal wall layer changes and mesenteric lymphadenopathy––two findings that support intestinal inflammation or disease but do not differentiate type. Ultimately, intestinal biopsies, obtained either endoscopically or at exploratory surgery, are essential for both diagnosing IBD and ruling out other specific causes of GI clinical signs. Treating IBD At this time, therapy of IBD in cats continues to include inflammatory suppression and antibiotic therapy, and while evidence to support a specific role for probiotic therapy is 14 lacking, its use to help control dysbiosis or IBD seems to have merit. The most effective therapies for IBD include steroids (prednisolone or methylprednisolone, 1–2 mg/kg q12h PO) or other drugs that interrupt the proinflammatory pathways active in the gut. In cats intolerant to steroids or those in which steroids are no longer effective, immunosuppressive therapy may be necessary. Currently, either chlorambucil or cyclosporine is most frequently chosen. Metronidazole (5–10 mg/kg q12h PO) or tylosin (5–15 mg/kg q12h PO) has been effective for control of bacteria-associated disease and continues to be recommended for initial therapy of IBD. Whether this action can be attributed to the antibiotic effects of these drugs and their influence on the intestinal microflora or their immune-modulating activities is unknown. Nevertheless, such therapy is often helpful. Caution is advised in using either drug on a continuous or long-term basis but especially metronidazole due to its potential for genotoxicity. If needed, they should be used intermittently, not continuously. Studies of probiotic therapy in cats have primarily focused on the use of Fortiflora (Purina) in a shelter environment among kittens or young cats with parasitic diseases (giardiasis, cryptosporidiosis, etc) or stressinduced diarrhea. Under these circumstances, probiotic therapy resulted in a faster resolution of diarrhea and more rapid resolution of infection. However, placebo-controlled clinical trials using probiotics in cats with IBD are only in their early stages, so specific recommendations await their findings. Finally, general agreement exists among gastroenterologists that foods with fewer carbohydrates (a source of intolerance and maldigestion) and based on highly digestible protein sources (primarily meat) are beneficial in cats with IBD, reducing the bacterial changes that can occur when undigested foods remain in the GI tract. These formulations may include so-called hypoallergenic Vomiting Cat Cases: You Can Figure Them Out diets but do not necessarily require hypoallergenicity. A scoring system that can be used in monitoring response to treatment of IBD as well as to assist in diagnosis in cats in which IBD is suspected has been published by Albert Jergens et al.8 Extraintestinal Causes of Vomiting: Feline Pancreatitis & Cholangitis Management of Feline Vomiting Differentiate acute from chronic (>3 wk) Physical exam Mild, nonspecific cause Foreign body Mass Intussusception Supportive/ symptomatic therapy Endoscopy or surgery Laboratory data (CBC, serum biochemistry panel, UA GI panel, FeLV/FIV, T4, HW, fecal, etc) Nonspecific cause Supportive/ symptomatic therapy Imaging (radiographs, US) Nonsignifcant Specific cause - Renal - Infectious Symptomatic - Liver therapy - Pancreas - Endocrine (DM, Addison's, thyroid disease) - Cancer - Heartworm Foreign body Mass Organomegaly Etc Further diagnostics (biopsy) or therapy Specific & supportive therapy Feline pancreatitis is difficult Symptomatic/Supportive Therapy Specific Therapy to diagnose definitively anteIV fluids Antibiotics Blood transfusion Anthelmintics DM = diabetes mellitus, FeLV = feline leukemia virus, mortem, especially in its more FIV = feline immunodeficiency virus, HW = heartworm, Prednisone Chemotherapy T = thyroxine, UA = urinalysis, US = ultrasonography common lymphoplasmacytic Ursodiol Insulin or specific drugs Etc Surgery form, and is associated with vomiting only occasionally or intermittently.4,10 This difficulty is partly attributable to lack of both of cats to hide overt signs and the apparent specific clinical signs in cats and a highly response of cats given pain relief medication. sensitive test for diagnosis of the disease. Thus, clinical signs may be quite variable, The clinical signs of pancreatitis in cats can and this must be taken into consideration be quite different from those in dogs. Acute with each patient. necrotizing pancreatitis is frequently encounRoutine evaluation of vomiting cats with tered in obese dogs fed a high-fat diet, while suspected pancreatitis or other extra-GI causes cats are more likely to be underweight and of vomiting is similar to that mentioned above: high-fat diets do not appear to be an impora minimum database, GI function testing, and tant predisposing factor. Cats of all ages, sexes, retroviral testing are always appropriate. Tests and breeds are affected, although Siamese cats for hyperthyroidism, liver function, or other reportedly have the more acute, necrotizing specific tests may be indicated in some cats. form of pancreatitis more frequently. Hematologic findings in cats with panThe most common form in cats, lymcreatitis are nonspecific but may include phoplasmacytic pancreatitis, is more insidinonregenerative anemia, leukocytosis, or ous, and the clinical signs are vague, with leukopenia (less common). In a recent study, the most common being lethargy (100% of cats with pancreatitis consistently had elevated cats in one study), anorexia, and dehydrawhite blood cells (20,300/L) and mild detion.11 Vomiting and anterior abdominal creases in platelets (mean, 180,000/L). Neutrophils were not degenerate or toxic. Reported pain, which are common clinical signs in changes in the serum biochemistry profile indogs with acute pancreatitis, occur in only clude elevated serum alanine aminotransferase 35% and 25% of cats, respectively. How(ALT), elevated serum alkaline phosphatase ever, there is strong belief among feline prac(ALP), hyperbilirubinemia, hyper- or hypotitioners that pancreatic pain or discomfort cholesterolemia, hyperglycemia, azotemia, and may be underreported due to the tendency 4 Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 15 In cats with chronic pancreatitis, it is still necessary to evaluate the combined historical, physical examination, and laboratory data as well as imaging information, along with the fPLI results, when making a diagnosis. 16 hypokalemia. Common abnormalities in cats with severe pancreatitis were hyperglycemia (180 mg/dL), hyperbilirubinemia (2.5 mg/dL), hypocholesterolemia (130 mg/dL), and hypoalbuminemia (1.8 g/dL). In cats with mild or lymphoplasmacytic pancreatitis, liver enzyme elevations were more common, with γ-glutamyl tranferase, ALP, and ALT being moderately elevated. Hypocalcemia is less commonly observed but, when present, may be a poor prognostic sign seen in cats with severe pancreatitis or multiple-organ dysfunction. Serum lipase may be increased early in acute pancreatitis, but in a recent study, amylase and lipase were found to be of little diagnostic value in distinguishing normal cats from those with pancreatitis. There are no changes in the urinalysis consistently observed or specific for pancreatitis in cats. The feline trypsin-like immunoreactivity (fTLI) test is the definitive test for diagnosis of exocrine pancreatic insufficiency. While an increase in fTLI can be found in cats with pancreatitis, a normal value does not rule out pancreatitis, as the leakage of enzymes tends to decrease rapidly following an event and the enzymes are inactivated and scavenged by the body’s peptidases (eg, macroglobulin) within 12 to 24 hours following an acute insult. This test is very useful in cats with chronic pancreatitis, however, as they may sustain a loss of pancreatic function, indicated by a decreased fTLI. In fact, in a recent unpublished study by the author's group of 150 cats with exocrine pancreatic insufficiency tested at the Texas A&M GI laboratory, the most common clinical sign was weight loss (85%) not diarrhea (45%) or vomiting. Thus, measurement of fTLI is an important aspect of assessment in cats with chronic low-grade inflammation of the pancreas that may not have overt signs of inflammation or illness but have lost significant pancreatic functional capacity. The test of choice for pancreatic leakage is the radioimmunoassay for feline pancreatic lipase (fPLI); this test has a sensitivity and specificity of nearly 100% in cats with severe pancreatitis (determined by pancreatic biopsy).12 However, the sensitivity in moderate pancreatitis was found to be 80% and as low as 65% in mild pancreatitis, while the specificity in healthy cats was 75%. Thus, in cats with suspected chronic pancreatitis, it is still necessary to evaluate the combined historical, physical examination, and laboratory data as well as imaging information, along with the fPLI results, when making a diagnosis. Imaging Studies Imaging studies are frequently used to help identify cats with acute pancreatitis, but in those cats with the more common chronic form, changes on ultrasound imaging can be particularly subject to interpretation and operator expertise. The most common ultrasonographic findings are hypoechoic pancreas, hyperechoic mesentery, mass effect, dilated common bile duct, or normal appearance throughout. In a recent study, mild pancreatitis was still shown to be difficult to diagnose via abdominal ultrasound imaging, but ultrasound was 80% sensitive and 88% specific in cats with moderate to severe pancreatitis.13 The most reliable method for making an accurate diagnosis of pancreatic disease remains direct visualization and histopathology. This approach can be expensive and can increase the risk for complications (during anesthesia/surgery). In cases with focal involvement, which is common with chronic pancreatitis, lesions may be missed. In short, pancreatitis remains a challenging diagnosis and an even more challenging disease to treat once the diagnosis has been confirmed. Feline Liver Diseases (Cholangitis, Idiopathic Hepatic Lipidosis) Cats have four major types of liver disease: Vomiting Cat Cases: You Can Figure Them Out hepatic lipidosis, cholangiohepatitis complex, infectious hepatitis (eg, feline infectious peritonitis, toxoplasmosis, fungal/parasitic hepatitis), and neoplastic liver disease (eg, lymphoma). As with most diseases of the liver, histopathology is an important step in determining treatment and prognosis. Nevertheless, once a diagnosis has been obtained, the goal for treatment of cats with liver disease is to provide optimal nutritional and pharmacologic support that maximizes liver function; minimizes future liver or biliary duct damage or scarring; controls concurrent clinical signs, such as vomiting; and thus promotes a high quality of life. Inflammatory, infectious, or metabolic liver disease can be present in cats with few external clinical signs other than inappetence, vomiting, or lethargy or can cause severe illness resulting in development of ascites, icterus, hepatoencephalopathy, coagulopathy, and loss of ability to metabolize protein or carbohydrates appropriately. Thus, there is no single set of clinical signs or laboratory abnormalities that can define all liver disease patients. Nevertheless, some important clues can help guide the clinician to making a definitive diagnosis. The most common cause of severe liver disease or failure in the cat is idiopathic hepatic lipidosis, but the most common cause of increased liver enzymes and chronic intermittent clinical signs is cholangitis/cholangiohepatitis. In several recent studies using biopsy results to confirm diagnosis, cats with inflammation of the peribiliary structures consistent with cholangitis also had lymphoplasmacytic infiltrate in the pancreas (66%–75% in separate studies).13,14 Thus, there is growing evidence that these two diseases in cats may be linked: when one occurs, the other follows. At this time, there is no agreement about cause; however, there is some evidence that bacteria may be an important culprit, as bacterial DNA was found in at least 30% of livers with a neutrophilic inflammatory component.15 Con- versely, in another article, no bacterial DNA was found, but the majority of study cats had the more chronic lymphocytic form of the disease.16 Whether this dichotomy represents two separate diseases or different stages/phases of the same disease (acute progressing to chronic) is unknown, but it suggests that further work to better control and define the origin of intestinal dysbiosis in cats is warranted. Finally, a number of other important extraGI causes of vomiting also need to be considered, including chronic renal disease, endocrinopathies (eg, hyperthyroidism, diabetic ketoacidosis), and other systemic diseases (eg, heartworm disease). A complete discussion of each is not possible, but readers are reminded to consider these possibilities when confronted with vomiting cats for which a definitive diagnosis has not been made. Nonspecific Therapy of Vomiting Several antiemetic agents are available for use in cats (Table 3); some are more commonly used in the hospital setting because they are injectable and may require frequent administration. The newest antiemetic drug family, neurokinin (NK) inhibitors, represented by maropitant, are clearly the most effective in cats. In addition to the excellent antinausea effects of maropitant, it also appears to be effective for controlling visceral pain, which may be an essential aspect of therapy in feline chronic pancreatitis and other visceral causes of vomiting. The feline dose is 1 to 2 mg/kg PO or SC q24h for 3 to 5 days, but it may be given longer if needed. The 5-HT3 antagonists are effective antiemetic agents for cats as well at doses of 0.5 to 1.0 mg/kg of ondansetron, 0.1 to 0.5 mg/kg of granisetron, or 0.5 to 1.0 mg/kg of dolasetron PO or IV q12–24h. In addition, cats may be treated with chlorpromazine, an α2-adrenergic antagonist, at 0.2–0.4 mg/kg q8h SC or IM. Dopaminergic antagonists such as metoclopramide are less effective in the cat and, because they antagonize Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings In addition to the excellent antinausea effects of maropitant, it also appears to be effective for controlling visceral pain, which may be an essential aspect of therapy in feline chronic pancreatitis and other visceral causes of vomiting. 17 TABLE 3 Feline Doses for Antiemetic Drugs Drug Class Location of Action Drug Dose α2-Adrenergic antagonists Central (CRTZ/vomiting center) Prochlorperazine 0.1–0.5 mg/kg q8h SC Chlorpromazine 0.2–0.4 mg/kg q8h SC D2 dopaminergic antagonists Central (CRTZ) and peripheral (GI smooth muscle) Metoclopramide 0.2–0.4 mg/kg q6–8h SC H1 histaminergic antagonists Central (CRTZ) Chlorpromazine 0.2–0.4 mg/kg q8h SC Diphenhydramine 2–4 mg/kg q8–12h SC Dimenhydrinate 2–4 mg/kg q8–12h SC 5-HT3 serotonergic antagonists Central (CRTZ/vomiting center); peripheral (vagal afferents) Ondansetron 0.5–1.0 mg/kg q12–24h PO, IV Granisetron 0.1–0.5 mg/kg q12–24h PO, IV Dolasetron 0.5–1.0 mg/kg q12–24h PO, IV 5-HT4 serotonergic antagonists Peripheral (myenteric neurons) Cisapride 1.25–2.5 mg/cat q8–12h PO NK1 neurokinin antagonists Central (CRTZ/vomiting center) Maropitant 1–2 mg/kg q24h PO, SC CRTZ = chemoreceptor trigger zone While nonspecific therapy may be indicated to control vomiting, finding the cause is more important than simply controlling the clinical sign. 18 dopamine, may potentially reduce pancreatic blood flow. (This effect has not been proven in cats with pancreatitis.) While such nonspecific therapy may be indicated to control vomiting, finding the cause is more important than simply controlling the clinical sign. Thus, antiemetic therapy should be used judiciously in the clinical setting and as an adjunct to therapy for the primary problem. References 1. Adverse reactions to foods: Allergies versus intolerance. Roudebush P. In Ettinger SJ, Feldman EC (eds): Textbook of Veterinary Internal Medicine, ed 6––St Louis, MO: Elsevier, 2005, p 153. 2. Feline intestinal lymphoma. Richter K. Vet Clin North Am Small Anim Pract 33:1083-1098, 2003. 3. Acute and chronic vomiting. Simpson KW. In BSAVA Manual of Canine and Feline Gastroenterology, ed 2–– Gloucester, UK: British Small Animal Veterinary Association, 2005, pp 73-78. 4. Pancreatitis in cats: Diagnosis and management of a challenging disease. Zoran DL. JAAHA 42:1-9, 2006. 5. Medical management of hyperthyroidism. Trepanier LA. Vet Clin North Am Small Anim Pract 37:775-788, 2007. 6. Vomiting. Washabau RJ. In Canine and Feline Gastroenterology, 1st ed—St. Louis, MO: Elsevier, 2013, pp 167-173. 7. Adverse food reactions. Cave N. In Canine and Feline Gastroenterology, 1st ed—St Louis, MO: Elsevier, 2013, pp 398-407. 8. Clinical staging of inflammatory bowel disease. Jergens AE, Crandall JM. In August JR (ed): Consultations in Feline Internal Medicine, vol 5––St Louis, MO: Elsevier, 2006, p 127. 9. Subnormal concentrations of serum cobalamin (vitamin B12) in cats with gastrointestinal disease. Simpson KW, Fyfe J, Cornetta A, et al. J Vet Intern Med 15:26-32, 2001. 10. Prevalence and histopathologic characteristics of pancreatitis in cats. DeCock HE, Forman MA, Farver TB, Marks SL. Vet Pathol 44:39-49, 2007. 11. Evaluation of feline pancreatic lipase immunoreactivity and helical computed tomography versus conventional testing for the diagnosis of feline pancreatitis. Forman MA, Marks SL, DeCock HE, et al. J Vet Intern Med 18:807-810, 2004. 12. Ultrasonography of the normal feline pancreas and associated anatomic landmarks: A prospective study of 20 cats. Etue SM, Penninck DG, Labato M, et al. Vet Radiol Ultrasound 42:330-336, 2001. 13. Clinical features of inflammatory liver disease in cats: 41 cases (1983-1993). Gagne JM, Armstrong PJ, Weiss DJ, et al. JAVMA 214:513-516, 1999. 14. Feline cholangitis: A necropsy study of 44 cats (1986-2008). Clark JE, Haddad JL, Brown DC, et al. J Feline Med Surg 13:570-575, 2011. 15. Culture independent detection of bacteria in feline inflammatory liver disease. Twedt DC, Janeczko SD, et al. J Vet Intern Med 23:729, 2009. 16. Histopathologic features, immunophenotyping, clonality, and eubacterial fluorescence in situ hybridization in cats with lymphocytic cholangitis/ cholangiohepatitis. Warren A, Center S, McDonough S, et al. Vet Pathol 48:627-641, 2011. Suggested Reading Clinical differentiation of acute necrotizing from chronic nonsuppurative pancreatitis in cats. Ferreri J, Hardam E, Kimmel SE, et al. JAVMA 223:469-474, 2003. Vomiting Cat Cases: You Can Figure Them Out Nutrition for Senior Dogs: New Tricks for Feeding Old Dogs S Julie A. Churchill, DVM, PhD, DACVN College of Veterinary Medicine University of Minnesota St. Paul, Minnesota enior dogs commonly present to veterinarians for primary care and represent approximately one third of the pet dog population.1 Life spans are increasing and thus both the percentage and the age of elder dogs may be increasing.2 Pet owners perceive that most pets, including senior dogs, are healthy and do not require a therapeutic food,3 but they are still left with hundreds of pet foods from which to choose. Advice and information recommending the best food is available almost anywhere—from trainers to pet food retailers, from magazines, internet sources, and social media. It is important to remember, however, that there is no established AAFCO nutrient profile for a “senior” life stage; thus the nutrient content of products marketed for senior pets varies widely. This makes it even more critical for the veterinary health care team to play an active role in providing credible nutritional advice, especially for senior dogs that have unique nutritional concerns. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 19 Physiologic changes that occur in middleaged and senior dogs make them less tolerant of nutritional deficiencies or excesses. WHAT IS OLD? The point at which a dog progresses from adult to a senior or geriatric life stage is variable and subjective. Life expectancies vary widely among dogs depending on breed and body size. Aging changes can also be variable, including loss of senses (hearing or vision), reduced energy requirements and lean body mass, as well as a decline in various organ functions. The American Animal Hospital Association (AAHA) Senior Care Guidelines suggest that, with the exception of large-breed dogs, most dog breeds reach middle age by 7 to 8 years of age and should be considered seniors when they reach the last 25% of the predicted life span for their breed.4 Despite this arbitrary categorization, physiologic changes that occur in middle-aged and senior dogs make them less tolerant of nutritional deficiencies or excesses. Middle-aged dogs are “at risk” or more vulnerable to age-related health problems. Middle age may bring an increasing incidence of chronic diseases, many of which can be influenced by nutritional management.5 A vital component of preventive medical care thus TABLE 1 Initial Screen: Assessing for Nutritional Risk Factors History of: Treats/snacks/human foods >10% Inadequate information/inappropriate feeding/food Unconventional diets Previous/ongoing medical problems GI signs Life stage needs Time of spay/neuter PHYSICAL EXAMINATION Any abnormal BCS (≠5/9) Any MCS <3 Unintentional weight loss OR gain New medical condition Poor skin/hair coat Dental disease Adapted from Table 2, AAHA Nutrition Assessment Guidelines BCS = body condition score MCS = muscle condition score 20 Requires extended evaluation if (✔) should include a “senior” screen or health risk assessment for early detection of health problems and adjustments to care to prevent or slow onset of age-related diseases. Every senior health screen should include a thorough nutritional assessment followed by an individualized nutritional recommendation. THE NUTRITIONAL ASSESSMENT Before any diet changes are recommended, a nutritional evaluation should be performed. Each nutritional assessment and recommendation should include three components: the patient, the diet, and feeding management factors.6 An accurate diet history is invaluable when assessing the nutritional health of the patient and will be vital to formulating an individualized diet plan. Understanding the nutritional changes that occur with aging and identifying any changes in the individual patient can help the clinician better match the appropriate food with the patient’s unique needs. The patient, the food, and the pet owner’s feeding practices are interrelated and require reassessment. Health and nutritional status are not static, especially in senior pets, but rather a dynamic process worthy of continued reevaluation and treatment modifications to match changing needs of the pet. Patient Assessment An initial assessment of the patient can be done quickly and utilizes information collected as part of a health assessment: a complete medical and diet history and a thorough physical examination and appropriate lab work (eg, complete blood count, serum biochemical profile, urinalysis). The nutritional screening process (Table 1) can quickly identify patients with “nutritional” risks. Healthy seniors (those without identified risks) that are eating a nutritionally balanced diet, have a healthy body weight, good body and muscle condition scores (BCS, MCS), and are free of significant Nutrition for Senior Dogs: New Tricks for Feeding Old Dogs physical or laboratory abnormalities need no further evaluation at this time. A pet-specific nutrition assessment and recommendation for healthy seniors can be done quickly. Nutritional recommendations should include the specific name of food that matches the pet’s current nutritional needs, the amount and frequency for feeding, and a monitoring plan. In many of these patients, the feeding recommendation involves little or potentially no change, but should include a verification and validation for the owner that the current food and feeding plan meets the pet’s needs, and a documentation of the current feeding plan in the medical record. If nutritional risk factors or age-related problems are identified, an extended evaluation and management plan is indicated (Table 2). This in-depth evaluation should address some common age-related conditions that may be influenced by nutritional management: • Weight management: achieve or maintain a healthy body weight • Osteoarthritis • Cognitive dysfunction Diet Assessment A complete diet history is important for evaluating the pet’s current nutritional status. Ideally, the animal’s exact diet (brand and amounts eaten) should be obtained as well as all snacks, treats, and nutritional supplements by type and amount. The drug/supplement history should include questions about the use of food to administer medication, as it may comprise a significant portion of the dog’s intake. Diet history information combined with the patient assessment provides information about the patient’s daily caloric requirements and specific nutrient intake, which should be compared with the patient’s individual needs. For example, an overweight pet with a robust appetite should not be fed a calorie-dense TABLE 2 Extended Screening: Assessing Senior Dogs for Nutritionally Relevant Age-Related Factors Abnormal body condition • Is this pet overweight or underweight? Diet • Is the pet eating appropriate amounts of a balanced diet? • Assess appetite and intake • Assess ability to eat: prehension, mastication, swallowing for those underweight and/or with poor intake • Assess sensory input: smell, vision, palatability of food. Consider palatability enhancer if necessary Mobility and access to food and water • Is the pet able to walk? Access to food provided? Able to stand to eat? • Other pets or physical limitations impairing access? Mobility and exercise • Is the pet’s MCS normal (3/3)? • Presence of osteoarthritis, lameness, pain? These play a role in maintenance of comfort, fitness, and healthy BCS • Activity minimizes sarcopenia • Exercise and activity provide mental stimulation and environmental enrichment Cognitive function assessment • Disorientation/confusion: becomes lost or confused, fails to recognize familiar people? • Changed interactions with family members? Isolates or seeks attention less often? • Change in sleep/activity cycles? Wanders or paces, sleeps more in day, less at night? • Loss of house training (nonmedical reasons) BCS = body condition score MCS = muscle condition score product. Reducing the amount of a high-calorie product could lead to deficiencies of other essential nutrients and increase hunger or undesirable food-seeking behaviors. Feeding Management Assessment Feeding practices and preferences influence a pet’s intake. Determine whether other pets present competition or limit access to food. Determine whether food is accurately measured, how much / how often food is offered, and how much is eaten. Determine if there have been recent changes to the feeding plan and why, as well how the pet accepted those changes. This information will allow the veterinary team to determine the nutritional adequacy of the current diet, as well as help identify factors that could contribute to potential success or problems with adherence to a new recommendation. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 21 If no adjustments are made to the pet’s energy intake to account for the reduction in LBM, activity, and MER, then the senior pet will gain weight and the risk for obesity will increase. 22 Reassessment and Modification of Treatment Plan Nutritional assessment of senior pets is an ongoing process. Dogs experience a variable and wide variety of metabolic changes as they age. It is important to communicate and engage pet owners to create the expectation of continued reassessment and treatment modifications that accommodate the specific changes observed in each individual dog rather than adopting a “senior” protocol. A vigilant monitoring plan allows early detection of problems if they arise and a better opportunity to intervene or modify the pet’s individualized nutritional plan to improve its health. Partner with clients to help ensure success and maintain adherence to the feeding and monitoring goals. EFFECTS OF AGING ON NUTRITIONAL NEEDS Energy Aging results in changes to both structure and function of the gastrointestinal (GI) tract; however, no studies report clinically relevant differences in nutrient absorption between young adult and geriatric dogs.7 Maintenance energy requirement (MER) is defined as the energy required to keep an animal in a “maintenance state,” or maintaining a normal activity. MER varies depending on factors such as breed, health, neuter status, and age. As dogs age, MER decreases ~25%, with the greatest decrease at middle age (7 years).8 Loss of lean body mass (LBM) appears to be the primary factor influencing the reduction in energy requirements.9 Lean body mass accounts for about 96% of an animal’s basal energy expenditure.10 Aging dogs are less active, which also contributes to reduced LBM and MER. If no adjustments are made to the pet’s energy intake to account for the reduction in LBM, activity, and MER, then the senior pet will gain weight and the risk for obesity will increase. Body condition score should be closely monitored in older dogs to prevent obesity because unhealthy weight gain exacerbates many agerelated conditions. A higher protein to calorie ratio diet would be beneficial to promote ideal weight maintenance in senior pets identified at risk for obesity.11 Results from Purina’s lifetime study revealed lower disease incidence, later onset of disease, and increased life span in calorically restricted dogs. Dogs fed a 25% reduction compared with controls lived an average of 13.0 years compared with 11.2 years.12 Maintaining energy balance and avoiding unhealthy weight gain is one of the most important goals for senior dogs. Water Elder humans exhibit decreased thirst and drinking when challenged by fluid deprivation. Although not confirmed in dogs, a similar response is expected.5 Thus water intake should be monitored or ensured when elder dogs are exercising or exposed to hot environments. Senior dogs may also be at risk for dehydration if they have subclinical renal insufficiency. When a senior pet’s appetite is good but water intake is suspect, add water to the food to ensure adequate intake and hydration. Protein Protein requirements increase with age due to increased protein turnover and reduced protein synthesis.13,14 Healthy senior dogs do not benefit from protein restriction15 and may be harmed by limiting dietary protein.16 Protein restriction of seniors could be more detrimental than protein deficiency in younger animals.17 As a general guideline for estimating minimum daily protein needs, provide 2.55 g protein per kg body weight (BW) or ~1 g protein per lb BW.13,17-19 This level of protein intake should minimize risk for protein deficiency. Senior dogs, however, may need up to 50% more than this.13 Older dogs also require fewer calories, or less food, than younger dogs. Diets for older dogs should not only contain fewer calories but more protein or a higher protein:calorie Nutrition for Senior Dogs: New Tricks for Feeding Old Dogs ratio to meet age-related nutritional needs. Based on the diet history, assure the dog is meeting minimum daily protein needs (~1 g protein/lb BW minimum). Food with 25% of calories from quality protein should meet the needs of most healthy aged dogs and minimize loss of LBM. Assess MCS to monitor LBM. NUTRITIONAL INTERVENTION FOR SELECTED AGE-RELATED DISEASES Although the most common age-related conditions are best managed with a multimodal approach combining nutritional strategies, exercise or environmental enrichment, and possible medical management, this discussion focuses on nutritional management. Overweight/Obesity Hyperadiposity, the most prevalent form of malnutrition, contributes to many of the diseases linked with obesity.21-23 Still, pets that are overweight go unrecognized or may not have this health concern addressed. Based on the canine life span study,12 which demonstrated many negative health consequences of being overweight, weight management should remain a top priority for senior pets. Yet it remains one of the most significant health problems among middleaged and elder dogs. Monitor the pet’s diet, BW, BCS, and MCS at each visit. Once excess weight is diagnosed, action should be taken to achieve healthy BW and BCS. Creating a negative energy balance promotes weight loss. This is best achieved by feeding low-calorie foods with increased protein content and increased nutrient:calorie ratio to assure adequate intake of essential nutrients. Degenerative Joint Disease Osteoarthritis (OA) affects as many as 20% of dogs and obesity is recognized as a primary risk factor.24 Nutritional strategies for OA include the following: • Weight and Muscle Management Loss of excess body weight/fat can improve clinical signs of lameness in arthritic dogs.25 Strategies to maintain healthy body weight, BCS, and LBM and prevent sarcopenia should be prioritized for senior dogs. This can be achieved by selecting a complete and balanced diet that meets protein and other nutrient needs while providing the amount of calories to prevent excess body fat gain. The goal is to delay onset / prevent progression of OA. • Long Chain Omega-3 Fatty Acids (n-3) show the greatest evidence for synovial antiinflammatory effects26,27 compared with other nutraceuticals. Marine oils (eicosapentaenoic acid [EPA] > docosahexaenoic acid [DHA])28 are preferred with more effective antiinflammatory effects compared with shorter-chain flax or other plant-source n-3 oils. There is no standard accepted dose. Cognitive Dysfunction As many as 20% to 68% of middle-aged to elderly dogs experience cognitive dysfunction or behavioral changes, which can manifest in varying degrees of mental decline29 (see Table 2). Nutraceuticals may have potential use both in prevention and treatment, but are best when combined with environmental enrichment.30-32 • Antioxidants The brain is especially susceptible to free radical damage and cognitive dysfunction. Multiple studies have shown improved clinical signs of age-related cognitive changes in dogs fed antioxidant-enriched diets or supplements.30-32 • Medium Chain Triglycerides (MCTs) Supplementation with MCTs has been shown to improve cognitive performance and preserve brain structure of elder dogs. MCTs provide an alternative cerebral energy source by way of ketones without restricting dietary carbohydrate or proteins.34,35 • Supplements versus Enriched Diets One caveat for using nutraceutical supplementa- Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings As many as 20% to 68% of middleaged to elderly dogs experience cognitive dysfunction or behavioral changes, which can manifest in varying degrees of mental decline.29 23 tion is that that these supplements have not been adequately assessed for efficacy, optimal doses, or nutrient interactions. When considering a diet containing the supplement or prescribing a supplement, assess the nutrient composition of the “base diet.” Confirm that the base diet meets the macronutrient needs of the patient and that it will provide an adequate dose of the intended supplement as fed. If not, it would be prudent to select a more appropriate diet and give the intended dose of supplement. REFERENCES When considering a diet containing the supplement or prescribing a supplement, assess the nutrient composition of the “base diet.” 24 1. Banfield Pet Hospital State of Pet Health Report (2013). Accessed September 1, 2014 from http://www.stateofpethealth.com/Content/pdf/Banfield-State-of-Pet-HealthReport_2013.pdf 2. Total pet ownership and pet population. US Pet Ownership & Demographics Sourcebook. Schamburg, IL: American Veterinary Medical Association. AVMA Membership & Field Services, 2012, pp 1-49. 3. Pet feeding practices among dog and cat owners in the United States and Australia. Laflamme DP, Abood SK, Fascetti AJ, et al. JAVMA 232:687-694, 2008. 4. AAHA Senior Care Guidelines for Dogs and Cats. Epstein M, Kuehn NF, Landsberg G, et al. JAAHA 41:81-91, 2005. 5. Age-related changes in nutrient utilization by companion animals. Fahey GC, Barry KA, Swanson KS. Annu Rev Nutr 28:425-445, 2008. 6. AAHA Nutritional Assessment Guidelines for Dogs and Cats. Baldwin K, Bartges J, Buffington T, et al. JAAHA 46:285-296, 2010. 7. Nutrition of aging dogs. Larsen JA, Farcas A. Vet Clin Small Anim Pract 44:741-759, 2014. 8. Effect of age on maintenance energy requirements and apparent digestibility of canine diets. Laflamme DP, Martineau B, Jones W, et al. Compend Contin Educ Pract Vet 22(suppl 9A);113, 2000. 9. Factors influencing lean body mass in aging dogs. Kealy RD. Compend Contin Educ Pract Vet 21:34-37, 1998. 10. The inter-organ flux of substrates in fed and fasted man, as indicated by arterio-venous balance studies. Elia M. Nutr Res Rev 4:3-31, 1991. 11. AAHA Weight Management Guidelines for Dogs and Cats. Brooks D, Churchill J, Fein K, et al. JAAHA 50:1-10, 2014. 12. Effects of diet restriction on life span and age-related changes in dogs. Kealy RD, Lawler DF, Ballam JM, et al. JAVMA 220:1315-1320, 2002. 13. Determination of optimal dietary protein requirements of young and old dogs. Wannemacher RW Jr, McCoy JR. J Nutr 88:66-74, 1966. 14. Age-related changes in protein synthesis. Richardson A, Birchenall-Sparks MC. Rev Biol Res Aging 1:255-273,1983. 15. The influence of dietary protein, lipid, phosphorus and sodium on renal structure and function in geriatric dogs. Churchill J, PhD thesis. Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN, 2001. 16. Effect of moderate protein deficiency on immune function. McMurray DN. Compend Contin Educ Pract Vet 21:21-24, 1999. 17. Nutrition for aging cats and dogs and the importance of body condition. Laflamme DP. Vet Clin North Am Small Anim Pract 35:713-742, 2005. 18. Survey of opinions about nutritional requirements of senior dogs and analysis of nutrient profiles of commercially available diets for senior dogs. Hutchinson D, Freeman L, Schreiner K, et al. Intern J Appl Res Vet Med 9(1):68-70, 2011. 19. Nutrient Requirements of Dogs and Cats. National Research Council. The National Academies Press. Washington, DC, 2006, p 119. 20. Beneficial effects of dietary mineral restriction in dogs with marked reduction of functional renal mass. Brown SA, Crowell WA, Barsanti JA, et al. J Am Soc Nephrol 1:1169-1179, 1991. 21. The effects of obesity-associated insulin resistance on mRNA expression of peroxisome proliferator-activated receptor-γ target genes, in dogs. Gayet C, Leray V, Saito M, et al. Br J Nutr 98:497-503, 2007. 22. Comparison of adipokine concentrations and markers of inflammation in obese versus lean dogs. Eirmann LA, Freeman LM, Laflamme DP, et al. Intern J Appl Res Vet Med 7:196-205, 2009. 23. Improvement in insulin resistance and reduction in plasma inflammatory adipokines after weight loss in obese dogs. German AJ, Hervera M, Hunter L, et al. Dom Anim Endocrinol 37:214-226, 2009. 24. Osteoarthritis and body weight. Foye PM, Stitik TP, Chen B, et al. Nutr Res 20:899-903, 2000. 25. Effect of weight reduction on clinical signs of lameness in dogs with hip osteoarthritis. Impellizeri JA, Tetrick MA, Muir P. JAVMA 216:1089-1091, 2000. 26. Effects of different n6:n3 fatty acid ratio diets on canine stifle osteoarthritis. Bartges JW, Budsberg SC, Pazak HE. Orthopedic Research Society 47th Annual Meeting, 2001. 27. Effects of feeding a high omega-3 fatty acids diet in dogs with naturally occurring osteoarthritis. Moreau M, Troncy E, Del Castillo JR, et al. J Anim Physiol Anim Nutr (Berl) 97:830-837, 2012. 28. Dietary eicosapentaenoic acid and docosahexaenoic acid equally incorporate as decosahexaenoic acid but differ in inflammatory effects. Sierra S, Lara-Villoslada F, Comalada M, et al. Nutrition 24:245-254, 2008. 29. Prevalence and risk factors for behavioural changes associated with age-related cognitive impairment in geriatric dogs. Zakona G, Garcia-Belenguer S, Chacon G, et al. J Small Anim Pract 50:87-91, 2009. 30. BDNF increases with behavioral enrichment and an antioxidant diet in aged dog. Fahnestock M, Marchese M, Head E, et al. Neurobiol Aging 33(3):546-554, 2012. 31. Synergistic effects of long-term antioxidant diet and behavioral enrichment on beta-amyloid load and nonamyloidogenic processing in aged canines. Pop V, Head E, Hill MA, et al. J Neurosci 30:9831-9839, 2010. 32. Nutritional management of brain aging in dogs. Roudebush P, Zicker SC, Cotman CW, et al. JAVMA 227:722728, 2005. 33. Enhancing brain functions in senior dogs: A new nutritional approach. Pan Y. Topics in Comp Anim Med 26:1,10-16, 2011. 34. Dietary enrichment with medium chain triglycerides (AC-1203) elevates polyunsaturated fatty acids in the parietal cortex of aged dogs: Implications for treating age-related cognitive decline. Taha AY, Henderson ST, Burnham WM. Neurochem Res 34:1619-1625, 2009. 35. Dietary supplementation with medium-chain TAG has long-lasting cognition-enhancing effects in aged dogs. Pan Y, Larson B, Araujo JA, et al. Br J Nutr 103:1746-1754, 2010. Nutrition for Senior Dogs: New Tricks for Feeding Old Dogs Pet Food Myth Busters: Answering Common Questions Owners Ask About Pet Food Lisa M. Freeman, DVM, PhD, DACVN Cummings School of Veterinary Medicine Tufts University North Grafton, Massachusetts M any owners make decisions about pet foods based not on fact, but on the many current myths and misconceptions that prevail. The first step to dispelling pet food myths is to be aware of what your patients are eating. A complete diet history for every patient at every visit is important for a number of reasons. Knowing what a patient is eating can help to diagnose health concerns—for example, if owners are feeding an unbalanced homemade or vegetarian diet; foods with potential hazards, such as raw meat diets (or other raw products, such as rawhides, bully sticks, or freeze-dried treats); commercial diets that are not nutritionally complete and balanced; or diets manufactured by companies with questionable nutritional and quality control protocols. The diet history also can help to determine whether the current diet is optimized for maintaining health or, in the case of animals with medical conditions, for helping to manage disease. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 25 Providing reliable nutrition resources and helping owners understand how to make more objective decisions about what they read or hear can help to ensure their pets are receiving optimal nutrition. In addition to collecting information on the animal’s current diet, which includes the pet food, treats, table food, rawhides, dental products, dietary supplements, and foods used to administer medications, it also is important to make a specific recommendation about the animal’s diet. This may be as simple as saying, “You’re feeding an excellent diet to Fluffy and are keeping her in perfect body condition. Keep up the good work!” Supporting sound nutrition decisions can help to reinforce these behaviors and makes it less likely that the owner will seek out nutritional information from other less reliable sources. Conversely, if the owner is feeding a diet that is not optimal, make a specific recommendation for a more appropriate diet (or treats, supplements, etc) and explain why you’re making this recommendation. Providing reliable nutrition resources and helping owners understand how to make more objective decisions about what they read or hear can help to ensure their pets are receiving optimal nutrition. In addition, it is important for the veterinary healthcare team to be prepared with answers to common questions and to be able to debunk myths. Some of the common questions owners ask are below.a COMMON MYTHS What is the best food to feed my pet? Despite all the marketing claims to the contrary, there is no best diet for all pets. Every pet is unique, so the goal is to find the best food for the individual pet. Expense doesn’t necessarily equate with quality. Some inexpensive foods have years of rigorous scientific testing behind them and some very expensive foods lack vital nutrients or are based on unsound science. Larger companies generally have more stringent quality control protocols, employ expert nutritionists and food scientists, and strive to increase collective nutrition knowledge through re- search. Smaller manufacturers may have less control over ingredient or final product quality, perform less laboratory testing, and are less likely to employ full- or part-time veterinary nutritionists. Is the ingredient list a good way to determine the quality of a pet food? Although ingredient lists are commonly used by lay people to determine the quality of pet foods, this approach has many pitfalls and can be subject to intentional manipulation by the food manufacturer. Ingredients are listed on labels in order of weight, including water, so ingredients with high water content (like fresh meats and vegetables) are listed before similar amounts of dry ingredients, even though they may contribute fewer nutrients overall. Pets require nutrients, not ingredients. A food full of great-sounding ingredients can be less nutritious than one containing less appealing (to people) ingredients. Some manufacturers may add ingredients to products solely for marketing purposes, to increase the appeal of the food to consumers. These ingredients may have unproven benefits, be present in miniscule amounts, and provide nothing to the food but added expense. More ingredients also mean increased quality control measures (and more time and expense) are necessary to ensure that the finished product adheres to the desired nutrient formulation. a Modified from Tufts University’s Cummings School of Veterinary Medicine Nutrition website: http://vet.tufts.edu/nutrition/faq/general_pet_nutrition.html). 26 Pet Food Myth Busters My friend says that grains are bad for dogs. Is this correct? Whole grains, rather than being fillers, contribute valuable nutrients including protein, vitamins, minerals, essential fatty acids, and fiber to foods while helping to keep the fat and calories lower than if animal products were used in their place. Even refined grains such as white rice can have beneficial health implications depending on the type of food and the pet. Dogs and cats can efficiently digest and use nutrients from grains. Allergies to grains (and even to animal proteins such as chicken, beef, and dairy) are actually very uncommon in dogs and cats. It is becoming more common in the saturated pet food market for manufacturers to perpetuate myths to sell products and increase market share. Grain-free foods are often an example of this strategy. Many such products merely substitute highly refined starches such as those from potatoes or tapioca in place of grains. These ingredients often provide fewer nutrients and less fiber than whole grains while costing more. I read online that by-products can include hair, hooves, and floor sweepings. Is this true? By-products are commonly vilified, often by pet food manufacturers that are trying to carve out market share for themselves. By-products (mainly organ meats and entrails) often provide more nutrients than muscle meats on a per-weight basis and are important components and even delicacies of human diets in other countries. The term by-product indicates that the ingredient is a leftover from animal carcasses once the desirable (for Americans) muscle meat has been removed. The Association of American Feed Control Officials (AAFCO) definitions of mammalian by-products specifically exclude hair, hooves, horn, hide trimmings, manure, and intestinal contents as well as anything that is not specifically part of the carcass (eg, floor sweepings). As with all ingre- dients, the quality of by-products can vary, so it is important to select manufacturers that have stringent internal quality control standards. I’ve heard that raw diets prevent and/or solve a lot of health problems in pets. Is this true? Despite anecdotal reports from pet owners and even some veterinarians, there is currently no evidence that raw foods offer any benefits over cooked ones. There is substantial evidence, however, that raw foods may be associated with nutritional deficiencies, bacterial and parasitic infections, and other health concerns in pets. These foods also pose potential risk to people—especially those that are immunocompromised, such as young children, the elderly, and patients receiving immune-modifying drugs or who have cancer. Pets that eat contaminated raw foods have been demonstrated to shed viable pathologic organisms in their feces, and it is likely that areas that they frequent also are contaminated. As numerous recalls and some pathogen surveys in the last few years have proven, all raw meat, regardless of source, should be considered to be contaminated until proven otherwise. In addition to food safety concerns, nearly all home-prepared raw diets and many commercially available raw products are deficient in essential nutrients. It is also common for commercial raw products to be very high in fat, which may not be tolerated by some animals. Check the list of recommended websites at the end of this article for information about raw meat diets. There is substantial evidence that raw foods may be associated with nutritional deficiencies, bacterial and parasitic infections, and other health concerns in pets. These foods also pose potential risk to people. Are home-cooked foods healthier for my pet than commercial products? High-quality commercial pet foods have been tested over decades to provide adequate nutrition for the dog or cat. With the exception of some pets with multiple or severe health concerns, there is a commercial food that is appropriate for every pet, and nutri- Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 27 is important to reduce calories after surgery to reduce the risk for obesity. HELPING OWNERS TO MAKE INFORMED DECISIONS ABOUT PET FOOD With the exception of some pets with multiple or severe health concerns, there is a commercial food that is appropriate for every pet, and nutritional deficiency diseases are rare in pets that are fed good quality commercial products. 28 tional deficiency diseases are rare in pets that are fed good quality commercial products. While home-cooked foods allow more control of ingredients and customization to the specific pet, most home-cooked food recipes are not formulated by a qualified veterinary nutritionist and are vague and deficient in multiple essential nutrients, making them much less nutritious than commercial foods. Even when the recipe is nutritionally balanced, there is no evidence that the average animal receives better nutrition from a homecooked food than a commercial food. For the vast majority of pet owners, commercial pet foods offer the best nutrition with the most convenience and affordability. What is the best diet for a growing puppy or kitten? Growing kittens should be fed a kitten food or an “all life stages” formula until 1 year of age. Growing small- and medium-breed puppies need a puppy or “all life stages” formula until 1 year of age. Large- and giantbreed puppies (adult size >50 lb) need a food specifically designed for large-breed puppies until 12 to 18 months of age. It is ideal if the product has passed AAFCO feeding trials rather than merely being “formulated to meet” the nutrient profiles for growth. Throughout growth, it is important to keep a puppy or kitten lean to reduce risks for health problems and to optimize its life span. Spaying or neutering reduces calorie requirements, so it An owner’s decision about what to feed his or her pet has become a more complicated question than it once was. There is no single “best” food for all pets because optimal diet(s) depends on many factors, such as life stage, body condition, exercise (or lack thereof ), environment, and health status. Often owners base their decisions on marketing messages rather than objective nutritional data. Although there are limitations, the information provided on a pet food label can provide helpful guidance for making objective selections of appropriate foods. The two most useful pieces of information on a pet food label are the nutritional adequacy statement and the manufacturer. Nutritional Adequacy The AAFCO adequacy statement must be included on all pet food labels in the United States. This statement confirms three important facts: 1. Whether the diet is complete and balanced. All over-the-counter foods should be complete and balanced. If the statement reads “for intermittent or supplemental use only,” it is not complete and balanced. The product may be acceptable as a veterinary therapeutic food to be used for a specific purpose––eg, in a case of severe kidney disease––but should be avoided for everyday feeding. 2. If the food is complete and balanced, for which life stage is it intended? AAFCO provides nutrient profiles and feeding trial requirements for growth, reproduction, and adult maintenance but not for senior/geriatric status. A food that is formulated to meet the AAFCO profiles for all life Pet Food Myth Busters stages must meet the minimum nutrient levels for both growth and adult maintenance. 3. How did the company determine that the food is complete and balanced? Labels may include one of two statements regarding nutritional adequacy: • “[Product name] is formulated to meet the nutritional levels established by the AAFCO Dog (Cat) Food Nutrient Profiles for [life stage(s)].” This determination is based either on the recipe or on analytic testing of the finished product (preferably the latter). • “Animal feeding tests using AAFCO procedures substantiate [product name] provides complete and balanced nutrition for [life stage(s)].” Feeding trial evaluation of food is the basis of this statement. While feeding trials help to test for the food’s nutritional adequacy, they do not guarantee that the food provides adequate nutrition under all conditions. In addition, I recommend that foods also be selected based on the important criteria below to help to ensure that the food is made by a reputable and knowledgeable company with strict quality control measures: THE MANUFACTURER The manufacturer’s name and contact information should be provided. The manufacturer should then be contacted for answers to the following questions: 1. If the product is tested using AAFCO nutrient profiles rather than feeding trials, does it do so by formulation or by analysis of the finished product? The latter is preferable. 2. Do they employ a full-time qualified nutritionist? What is this nutritionist’s name and qualifications? Appropriate qualifications are either a PhD in animal nutrition or board certification by the American College of Veterinary Nutrition or the European College of Veterinary Comparative Nutrition. Who formulates their foods and what are his/her credentials? 3. Where are their ingredients produced and their food manufactured? 4. What specific quality control measures do they use to assure the consistency and quality of ingredients and the end product? Examples include certification of a manufacturer’s procedures (eg, by Hazard Analysis and Critical Control Points, Global Food Safety Initiative, or American Feeding Industry Association); testing ingredients and end products for nutrient content, pathogens, and aflatoxins; materials risk assessments; and supplier audits. 5. Can they (and will they) provide information on levels for any requested nutrient (protein, phosphorus, sodium, etc) for the dog or cat food in question? An average/typical analysis is preferable as a guaranteed analysis provides only the minimums or maximums and not an exact number. These values should ideally be given on an energy basis (ie, grams per 100 or 1,000 kilocalories) rather than on an “as fed” or “dry matter” basis. The latter two do not account for the variable energy density of different foods. 6. What is the caloric value per gram, can, or cup of the food? 7. What kind of product research has been conducted? Are the results published in peer-reviewed journals? If a manufacturer cannot/will not provide any of this information, one should be cautious about using that brand. If a manufacturer cannot/will not provide any of this information, one should be cautious about using that brand. Critical Updates on Canine & Feline Health • 2015 NAVC/WVC Proceedings 29 RECOMMENDED WEBSITES Nutrition Guidelines • World Small Animal Veterinary Association Nutritional Assessment Guidelines – wsava.org/educational/ global-nutrition-committee • American Animal Hospital Association Nutritional Assessment Guidelines – aahanet.org/Library/NutritionalAsmt.aspx Tools for the Veterinary Health Care Team • World Small Animal Veterinary Association Nutrition Toolkit – wsava.org/nutrition-toolkit • Pet Nutrition Alliance – petnutritionalliance.org/ Pet Nutrition – General Information for Pet Owners • National Research Council downloadable booklets: Your Dog’s Nutritional Needs and Your Cat’s Nutritional Needs – dels.nas.edu/global/banr/petdoor • World Small Animal Veterinary Association Nutrition Toolkit (The Savvy Dog Owner’s Guide to Nutrition on the Internet, The Savvy Cat Owner’s Guide to Nutrition on the Internet, and Selecting the Best Food for Your Pet) – wsava.org/nutrition-toolkit Pet Nutrition – General Information for Veterinarians (Nutrition Myths) • Cummings School of Veterinary Medicine at Tufts University Nutrition Service Frequently Asked Questions – vet.tufts.edu/nutrition/faq • Nestlé Purina Nutrition Myths – purinaveterinarydiets.com/ healthandnutrition/myths/default.aspx • P&G Deciphering Fact from Fiction (co-written by Dr. Freeman) – iamsvetformula.com/loadFactFrom Fiction.do 30 Commercial Pet Food • Association of American Feed Control Officials: Information on regulations, labeling, and other important facts about pet food – petfood.aafco.org/ • FAQs about pet foods – vet.tufts.edu/nutrition/faq • Federal Drug Administration (FDA) Pet Food site: Information, links, food safety issues, recalls, pet food labels, reporting portal – fda.gov/AnimalVeterinary/Products/ AnimalFoodFeeds/PetFood/default.htm • Pet Food Institute: Information on ingredient definitions, nutrition myths, labeling regulations – petfoodreport.com Home-Cooked Pet Food • Cummings School of Veterinary Medicine at Tufts University Nutrition Service Frequently Asked Questions – vet.tufts.edu/nutrition/faq • American College of Veterinary Nutrition: Listing of board-certified veterinary nutritionists who will formulate nutritionally balanced homemade food recipes for veterinarians and/or pet owners – acvn.org • BalanceIT: Commercial website that offers semi-customized balanced homecooked food recipes for pet owners with healthy pets. Veterinarians can customize preformulated recipes for animals with medical conditions. – balanceit.com Dietary Supplements • Consumerlab: Site (with a small subscription fee for use) that independently evaluates dietary supplements (primarily for human supplements but some pet supplements are included) – consumerlab.com • Food and Drug Administration (FDA): Regulatory and safety issues of dietary supplements, adverse event reporting – fda.gov/food/dietarysupplements/ default.htm • Mayo Clinic Drugs and Supplements Information: Fact sheets on human supplements and herbs – mayoclinic.com/health/ drug-information/DrugHerbIndex • National Institutes of Health (NIH) Office of Dietary Supplements: Evaluating supplements, fact sheets, safety notices, internet health info – ods.od.nih.gov • United States Department of Agriculture (USDA) Food and Nutrition Information Center: General supplement and nutrition information, links to a variety of dietary supplement websites – fnic.nal.usda.gov/dietary-supplements • United States Pharmacopeia Dietary Supplement Verification Program: Independent testing of dietary supplements (human supplements only) – usp.org/dietary-supplements/overview Raw Meat Diets • Cummings School of Veterinary Medicine at Tufts University Raw Diet Fact Sheet – vet.tufts.edu/nutrition/faq • Freeman et al. Current knowledge about the risks and benefits of raw meat–based diets for dogs and cats. JAVMA 2013; 243: 1549-1558 (free access). – avmajournals.avma.org/doi/abs/ 10.2460/javma.243.11.1549 Other • Ohio State Indoor Pet Initiative: Nutrition and other tips for optimizing the indoor pet’s environment – indoorpet.osu.edu/ • USDA Nutrient Database: Full nutrient profiles on thousands of human foods – nal.usda.gov/fnic/foodcomp/search Pet Food Myth Busters NOTES _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ 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