2012, Volume 1, Issue 1
¡CAUTION! Snake Bite Season Ahead
With the promise of Spring in Missouri
and all of the natural beauty that the
season brings, snakebites may be one
of the more unpleasant injuries
associated with this time of year. Being
prepared for the inevitable by refamiliarizing yourself with general management strategies
and CroFab® administration can make caring for a patient
with snakebite a less daunting experience.
Missouri is home to five venomous snakes, all of which
are pit vipers (crotaline). These include: Western pygmy
rattlesnake, Timber rattlesnake, Massasauga rattlesnake,
Cottonmouth, and several subspecies of Copperhead. The
epidemiology of venomous snake bites in the state of
Missouri differs from the rest of the nation with a
significantly higher incidence of Copperhead bites (87%)
as compared to US statistics (25%). (See Table 1)
MO Poison Center
Statistics
(Mar ’93 - Dec ’99)
Copperhead
Rattlesnake
Cottonmouth
87% (n = 518)
50-100 calls per
year
8.5% (n = 50)
~5 calls per year
4.5% (n = 25)
~2 calls per year
US Statistics
25%
65%
10%
Table 1
Snakes indigenous to Missouri can cause hemotoxic
effects which harm the blood clotting system when venom
is introduced into a victim during a bite. The venom
contains necrotic and hemorrhagic toxins including:
phospholipase A2 which damages cell membranes;
hyaluronidase which degrades connective tissue;
proteolytic enzymes which degrade tissue; coagulants and
anticoagulants which cause intravascular clotting and
platelet trapping; and hemolysins which destroy RBCs and
WBCs. These components spread slowly via the
lymphatic system.
Page 1
-
Considering the Use of CroFab®?
There is significant variation in crotaline bites due to
differences in venom composition and potency. While
copperhead venom is cytotoxic with minor hemotoxic
effects; rattlesnake venom possesses prominent cytotoxic
and significant hemotoxic properties.
A victim’s immediate fear response to a snake bite may
complicate the clinical picture by inducing vagal (i.e.
nausea, vomiting, dizziness, syncope, bradycardia,
hypotension, cold clammy skin) or hyper-adrenergic (i.e.
tachycardia, hypertension, and diaphoresis) responses.
Crotaline bites are highly unpredictable and can vary from
“dry” bites (~20% are dry bites) to severe tissue damage
and life threatening systemic effects. Local signs of an
envenomation include fang puncture wounds (multiple
teeth marks suggest a non-venomous snakebite); a rapid
onset (within 5 minutes) of sharp, burning pain at the bite
site; or a later onset (30 minutes to 6-8 hours) of edema,
erythema, and sometimes ecchymosis; with proximal
extension and progression of effects occurring up to 12-48
hours. The estimated fatality rate for copperhead bites is
<0.02% (2/10,000). Copperhead envenomation may be
accompanied by significant local tissue morbidity despite a
lack of systemic toxicity. The estimated fatality rate for
rattlesnake bites is 2.5-3% which is reduced to 0.35% with
the use of antivenom (3-4 deaths/1,000 envenomations).
After initial assessment to confirm a venomous snakebite
it is important to anticipate swelling with the removal of
jewelry, clothing, and shoes which may further
compromise the limb if edema worsens. Immobilization of
the limb in a slightly elevated position above (i.e. 4-5
inches) the level of the heart can slow the spread of
venom. This is accomplished with a sling in bites to the
upper extremity; and a recumbent position with elevation
on pillows in bites to the lower extremity. Do NOT apply
tourniquets or tight fitting, narrow bands due to the risk for
constriction of blood flow. Continuous assessment to
evaluate the progression of the bite includes marking the
lead edge of edema or erythema every 15-30 minutes and
measuring and recording the limb circumference proximal
to the bite.
Missouri Poison Center
2012, Volume 1, Issue 1
Medical management of snakebite is determined by the severity of presentation and progression of the bite.
(See Table 2) Management includes: 1) strict elevation of the limb 4-5 inches above the level of the heart, 2) adequate
pain management which is best achieved through the use of parenteral opiates such as morphine or fentanyl, and 3)
CroFab® administration for “moderate-to-severe” envenomations. Adjunctive treatment may include the administration of
benzodiazepines for anxiety, meticulous wound care, and tetanus prophylaxis.
Table 2 Severity of snakebite envenomation
Minimal
Local
Symptoms
Systemic
Symptoms
Hematologic
Laboratory
Abnormality
Swelling, erythema
and local changes
confined to several
inches above bite
None
None
Moderate
Swelling beyond elbow or knee but less
than full limb at 6-12 hours
GI changes: nausea, vomiting, abdominal
pain, diarrhea, strange taste
Neurologic changes:
paresthesia, weakness, chills, headache,
local fasciculation
CV changes: mild hypotension (sys BP
>90), tachycardia (HR 100-150)
INR >1.2
PT >20 sec
Fibrinogen* <150 mcg/mL
Platelets <150,000
Severe
Swelling of a full limb –
up to shoulder or hip and beyond with
local hemorrhage, ecchymosis, bullae,
etc.
Respiratory changes: dyspnea,
tachypnea, hypoxia, respiratory failure
Mental status changes: confusion,
lethargy, syncope, seizure, coma, psychosis.
Shock
INR >2
PT >50 sec
Fibrinogen* <50 mcg/mL
Platelets <50,000
Severe hemorrhage or threat of serious
bleeding
*Decreased fibrinogen is the best parameter to follow.
It is important to note that limb amputation increases with the use of constriction bands, tourniquets, or ice packs; all of
these interventions are contraindicated. Most snakebites deposit venom in the subcutaneous tissue instead of
intramuscularly; so edema is most often subcutaneous, not sub-fascial. As a result true compartment syndrome is rare
and fasciotomy is very rarely indicated. Early recognition of a rapidly progressing bite with significant hematologic
laboratory changes indicates the need for early administration of CroFab® to prevent progression of swelling and the
need for fasciotomy. Antivenom saves muscle tissue!
CroFab® (Crotalidae Polyvalent Immune Fab) works by neutralizing venom
toxins, facilitating redistribution away from target tissues and elimination
•
Meticulous wound care
from the body. CroFab® is recommended when significant clinical effects
•
Strict elevation of the limb
can be improved or prevented (i.e. coagulopathy can be improved, systemic
•
Adequate pain control
effects can be improved, extension of moderate-to-severe local swelling can
•
Careful monitor of edema
be prevented.) CroFab® is not indicated for self-limited bites of mild–tomoderate severity. Its use is reserved for bites resulting in significant
•
Careful monitor of lab changes
coagulopathy or other systemic involvement manifested by CNS, GI,
•
CroFab® only when indicated
cardiovascular, or pulmonary symptoms, and for bites graded as moderate•
Benzodiazepines for anxiety
severe or anticipated to become so within 6-12 hours of envenomation (i.e.
limb edema anticipated to reach past the elbow or knee at 6 hours post bite
despite meticulous attention to elevation.) When CroFab® is indicated, a total of 4 vials are usually sufficient for most
copperhead bites. Scheduled 2-vial “maintenance” dosing is no longer routinely recommended.
Snakebite Management Points
In summary, meticulous wound care and elevation of the affected limb, pain management, and judicious use of CroFab®
are the mainstays of treatment for snakebite envenomations. (See Snakebite Management Points)
Please visit www.crofab.com to learn recent (March 2012) updates to CroFab® prescribing information.
Specific changes relate to reconstitution and mercury content, etc.
Please contact the Missouri Poison Center at 1-800-222-1222 to consult with a specially trained registered nurse,
pharmacist or medical toxicologist for information regarding venomous snakebite mangement.
Page 2
Missouri Poison Center
2012, Volume 1, Issue 1
PoisonSafe Practices
Cut this public education article out of every issue to copy and distribute or post for your clientele!
National Poison Prevention Week (NPPW)
50th Anniversary
The Missouri Poison Center is celebrating the 50th anniversary of NPPW this
year, March 18 – 24, 2012. Every year, the third week of March is designated to
highlight the dangers of poisoning and the importance of poison prevention. We
invite you to join us in celebrating the 50th anniversary of Poison Prevention Week by
spring cleaning your home and making it poison safe for your children, pets and family.
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Spring Clean and Brush-Up on These Tips
Store all dangerous household products and chemicals out of
reach and out of sight of small children and pets.
Store all potential poisons in their original containers.
Never store potential poisons in containers used for eating
and drinking. (For example: Do not mix up a pesticide or
weed killer and then store it in a water bottle or milk jug.)
Leave the original labels on all products.
Lock up medicines.
Use child resistant caps/closures.
Always read the label before using and follow the
instructions on medicines, cleaners, pesticides, automotive,
lawn and garden products for their proper use.
Never refer to medicine as candy to a young child.
Avoid taking medicine in front of small children.
(They like to imitate you.)
Turn on a light when taking or giving medication.
When you are using household chemical products and medicines, never let them out of your sight,
even if you must take them along when answering the door or phone.
Clean out your medicine cabinet periodically and properly dispose of old and unused medicines.
Install carbon monoxide alarms in your home.
Know the names of plants located in and around the home.
It’s March, the snakes will be waking up soon!!
First Aid for Poisonous Snake Bites
♦
♦
♦
♦
♦
♦
♦
♦
♦
Remain calm.
Do not try to capture the snake.
Note time of the bite and remove all tight clothing or jewelry which may delay or hide swelling.
Call the poison center immediately at 1-800-222-1222 for instructions on all snake bites.
Immobilize the limb or body part at or slightly above heart level.
Wash the bite area with soap and water.
DO NOT use ice or a tourniquet.
DO NOT cut over the fang marks and try to suck out the venom.
Transport the patient to the closest hospital.
Just in case you need us…….
Program your cell phone with
the nationwide toll free number to call your
local poison center:
1-800-222-1222.
Page 3
Missouri Poison Center
2012, Volume 1, Issue 1
POISONALERT
A quarterly publication of the Missouri Poison Center
Missouri Poison Center Staff
Specialists in Poison Information
Rachel Andrews, RN, SPI; Anne Marie Bailey, RN,
CSPI; Maureen Bredenkoetter, RN, CSPI; Jenny Burt,
RN, CSPI; Linda Campfield, RN, CSPI; Jackie Coffey,
RN, CSPI; Jan Cocayne, RN, CSPI; Sue Dougan, RN,
CSPI; Barbara Eichhorn, RN, CSPI; Shelly Enders,
PharmD, CSPI; Darlene Green, RN, CSPI; Kathy
Hahn, BS Pharm, SPI; Sandra Heffner, RN, CSPI;
Peggy Huebner, RN, CSPI; Peggy Kinamore, RN,
CSPI; Joanne Menendez, RN, CSPI; Julie Moore, RN,
CSPI; Sue Nielsen, RN, CSPI; Carolyn Odom, RN,
CSPI; Amanda Ruback, RN, SPI; Joy Thompson, RN,
CSPI; Rosanna Tochtrop, RN, CSPI; Dianne Wagner,
RN, CSPI; Julie Weber, BS Pharm, CSPI; Janelle Williams, RN, CSPI; Jennifer Williams, PharmD, SPI
*CSPI denotes Certified Specialist in Poison Information
Please send comments and suggestions for future
articles to:
Editors, PoisonAlert
7980 Clayton Road, Suite 200
Saint Louis, MO 63117
Or send e-mail to [email protected]
The Missouri Poison Center website can be found at:
http://www.cardinalglennon.com. Click on Poison
Center under Support Services.
Managing Director
Julie A. Weber, BS Pharm, CSPI
Medical Director
Anthony J. Scalzo, MD
Assistant Medical Director
Rebecca Tominack, MD
Public Education Coordinator
Peggy Kinamore, RN, BSN, CSPI
Administrative Assistant
LaJohnna White
PoisonAlert Editors
Anthony J. Scalzo, MD
Julie A. Weber, BS Pharm, CSPI
PoisonAlert Contributors
Anne Marie Bailey, RN, CSPI
Jenny Burt, RN, CSPI
Shelly Enders, PharmD, CSPI
Peggy Kinamore, RN, CSPI
Carolyn Odom, RN, CSPI
Publisher
LaJohnna White
Page 4
National Poison Prevention Week
Public Education Materials
Missouri Poison Center is offering a variety of
educational materials FREE of charge including
magnets, stickers, and brochures. For a small fee,
you can order the Toxic Plants Brochure for your
garden club, the Bites and Stings Brochure for
your scout troop, or the Poison Look-Alikes
Brochure for your child care providers and
parents. Please help us teach about poison
prevention and spread the word that the
Missouri Poison Center is open 24/7 and
the call is free and confidential.
Missouri Poison Center