194
Brief Reports
the average MIC is Ç1 mg/mL [2]. However, the use of ciprofloxacin is contraindicated in children, who constitute the most common age group with CSD.
Azithromycin penetrates into both macrophages and neutrophils;
this uptake accounts for the extremely high ratio of 40 for intracellular-to-extracellular concentrations [5, 10]. It has also been suggested
that phagocytes may transport azithromycin into areas of inflammation and infection. Furthermore, a separate experiment demonstrated
that the concentration of azithromycin—but not that of clarithromycin
or erythromycin—remained high within the phagocytes when drugs
were removed from the incubation medium.
Azithromycin is highly effective against Bartonella species in a
cell-free medium, with an MIC ranging from 0.006 to 0.015 mg/mL,
which is far below the achievable intracellular concentration. The
preferential concentration of azithromycin within infected lymph node
tissue and phagocytic cells may be the reason for the drug’s effectiveness against sequestered yet drug-susceptible B. henselae.
The optimal dose and duration of azithromycin therapy for patients
with CSD was not adequately addressed in this study. A 5–7 day
course of therapy may be enough because of the long tissue half-life
and high intracellular concentration of this drug. Although the true
effectiveness of antibiotics for the treatment of CSD cannot be established without a controlled trial, our preliminary data, along with the
aforementioned scientific basis, should encourage the use of azithromycin for the treatment of symptomatic cases of CSD.
John K. S. Chia, Michael M. Nakata, Jose Luis M. Lami,
Susan S. Park, and James C. Ding
Torrance Memorial Medical Center, Torrance, California
Note Added in Proof
Since the acceptance of this paper, we have treated five more
patients with bartonella lymphadenitis, confirmed by serology or by
Proteus Pyomyositis of the Piriformis Muscle in a
Swimmer
Nontropical or ‘‘temperate’’ pyomyositis, a bacterial infection
of skeletal muscle, has been reported with increasing frequency
over the past 2 decades, although it remains an unusual infection
in children [1, 2]. Pyomyositis most commonly involves the large
muscles of the extremities, often after muscular trauma or exertion
[1–5]. Gram-positive organisms are the usual etiologic agents [1,
2]. We recently treated a boy who presented with a confusing
clinical picture of sepsis with severe back and leg pain suggestive
of an epidural abscess. The boy, a competitive swimmer, was
Reprints or correspondence: Dr. Michael J. Chusid, Department of Pediatrics, MFRC, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226.
Clinical Infectious Diseases 1998;26:194–5
q 1998 by The University of Chicago. All rights reserved.
1058–4838/98/2601–0036$03.00
CID 1998;26 (January)
detection of B. henselae DNA in a lymph node aspirate. Four patients
with painful, nonsuppurative lymph nodes ranging in size from
2.5 cm 1 3 cm to 7 cm 1 4 cm responded to 7–10 day courses of
azithromycin, with resolution of lymphadenopathy within 10–21
days. One patient with a completely fluctuant anterior cervical node
(2.5 cm 1 1.5 cm), who had received two prior courses of ciprofloxacin and clarithromycin, failed to respond to treatment with azithromycin; however, the lymph node gradually regressed after repeated
aspiration of pus.
References
1. Anderson B, Sims K, Regnery T, et al. Detection of Rochalimaea henselae
DNA in specimens from patients with cat-scratch disease by PCR. J
Clin Microbiol 1994; 32:942 – 8.
2. Maurin M, Gasquet S, Ducco C, Raoult D. MICs of 28 antibiotic compounds for 14 Bartonella isolates. Antimicrob Agents Chemother 1995;
39:2387 – 91.
3. Spach DH, Kanter AD, Dougherty BS, et al. Bartonella quintana bacteremia in inner-city patients with chronic alcoholism. N Engl J Med 1995;
332:424 – 8.
4. Guerra LG, Neira CJ, Boman D, et al. Rapid response of AIDS-related
bacillary angiomatosis to azithromycin. Clin Infect Dis 1993; 17:
264 – 6.
5. Gladue RP, Bright GM, Isaacson RE, Newborg MF. In vitro and in vivo
uptake of azithromycin by phagocytic cells: possible mechanism of
delivery and release at sites of infection. Antimicrob Agents Chemother
1989; 33:277 – 82.
6. Moriarty RA, Margileth AM. Cat-scratch disease. Infect Dis Clin North
Am 1987; 1:157 – 90.
7. Musso D, Drancourt M, Raoult D. Lack of bactericidal effect of antibiotics
except aminoglycosides on Bartonella henselae. J Antimicrob Chemother 1995; 36:101 – 8.
8. Bogue CW, Wise JD, Gray GF, Edwards KM. Antibiotic therapy for catscratch disease? JAMA 1989; 262:813 – 6.
9. Holley HP. Successful treatment of cat-scratch disease with ciprofloxacin.
JAMA 1991; 265:1563 – 5.
10. McDonald PJ, Pruul H. Phagocyte uptake and transport of azithromycin.
Eur J Clin Microbiol Infect Dis 1991; 10:828 – 33.
ultimately determined to have pyomyositis of the piriformis muscle
due to Proteus mirabilis.
A 17-year-old male was admitted to the hospital with fever and
severe leg and back pain. The pain worsened to the point that
walking became difficult. He was febrile (temperature to 1047F).
His WBC count was 18,900 cells/mL (87% polymorphonuclear
cells, 4% band forms, 3% lymphocytes, 1% eosinophils, and 5%
monocytes), his hematocrit was 45%, and his platelet count was
201,000 cells/mL. The erythrocyte sedimentation rate was 1 mm/h,
and findings of a urinalysis were unremarkable. Culture of urine
yielded no growth.
The patient underwent a neurosurgical evaluation because of
concern that he had an epidural abscess. On physical evaluation
he appeared to be unable to find a position of comfort. Straight
leg raises were limited to 557 on the left and 357 on the right.
There was no swelling over the back or pain to percussion. He
was a high school football player, but his last game had been
2 weeks before admission. He was also a competitive swimmer
(breaststroke) and had practiced vigorously 2 days before admission. He denied drug use or sexual activity.
CID 1998;26 (January)
Brief Reports
Figure 1. T2-weighted axial MRI image through the pelvis of a 17year-old male swimmer with pyomyositis of the piriformis muscle
due to Proteus mirabilis. The right piriformis muscle (arrow) is enlarged and edematous.
An MRI of the lumbar spine revealed an abnormal signal in the
right pyriformis muscle just anterior to the sacroiliac joint (figure
1). No epidural abscess was noted. Therapy with iv vancomycin
and cefotaxime was initiated after the blood cultures were performed. Morphine was required for pain relief.
The next day a technetium bone scan confirmed a lack of
involvement of osseous structures. A C-reactive protein level was
obtained because this acute-phase reactant often becomes elevated
before the erythrocyte sedimentation rate. The C-reactive protein
level was highly abnormal at 12.8 mg/L (normal range, õ1
mg/dL). The creatinine kinase level was high (1,113 IU/L [normal
range, 0–206 IU/L]), further suggesting muscle involvement. Two
blood cultures yielded P. mirabilis. Antibiotic therapy was
switched to cefotaxime and tobramycin. The patient became afebrile by the fourth hospital day. A CT of the abdomen and pelvis
with contrast medium demonstrated marked swelling of the right
piriformis muscle and bilateral pulmonary effusions that were too
small to tap. No gastrointestinal or gastrourinary lesions were
noted. Findings on a cardiac echogram were normal.
The patient was discharged from the hospital to complete 2
weeks of iv antibiotic therapy. By day 10 of treatment, the patient’s
C-reactive protein level had returned to normal (0.7 mg/dL), as
had his creatinine kinase level (67 IU/L). A follow-up CT showed
only minimal swelling of the piriformis muscle.
The development of pyomyositis is assumed to be secondary to
traumatic injury to a muscle during a period of bacteremia [1–5].
In an animal model of experimentally induced pyomyositis, muscle
infection did not occur in association with staphylococcal bacteremia unless the muscle was first physically damaged [6]. There
are reports of bacterial pyomyositis occurring in children after arm
wrestling or volleyball [3, 5]. It seems significant that this boy’s
infection developed in one of the pelvic muscles used in the frog
kick employed in his specialty event, the breaststroke.
195
Because of its location within the pelvis near the sciatic notch,
inflammation of the piriformis is often associated with severe sciatic pain, as was noted in our case [4, 7]. This can lead to the
erroneous conclusion that lumbar or epidural inflammation is present. Appropriate imaging techniques usually allow rapid diagnosis
of the actual area and nature of the infection [8].
Most cases of pyomyositis are due to gram-positive organisms,
particularly Staphylococcus aureus and Streptococcus pyogenes
[1, 2]. The few cases that are due to gram-negative organisms
have occurred primarily in patients with immunologic deficiencies
[9]. To our knowledge, there are no previously reported cases of
proteus pyomyositis.
The source of our patient’s organism is unknown. Findings of
an evaluation of the patient’s genitourinary and gastrointestinal
tracts were normal. There was no evidence of parenteral drug use,
and cardiac evaluation was unremarkable. Hot tubs and swimming
pools have been previously implicated in the development of invasive gram-negative infections, presumably through inhalation of
aerosolized organisms [10].
In most previously reported cases of pyomyositis, prolonged
(2–4 weeks) parenteral antibiotic therapy has been administered
after evacuation of a defined intramuscular abscess [1, 2]. It appears that in cases where frank suppuration has not occurred,
briefer therapy be effective, as long as disease resolution is documented by radiographs and laboratory test results.
Michael J. Chusid, Wendy C. Hill, Jennifer A. Bevan,
and Jack R. Sty
Departments of Pediatrics and Radiology, The Medical College of
Wisconsin, Milwaukee, and Children’s Hospital of Wisconsin,
Milwaukee, Wisconsin
References
1. Renwick SE, Ritterbusch JF. Pyomyositis in children. J Pediatr Orthoped
1993; 13:769 – 72.
2. Christin L, Sarosi GA. Pyomyositis in North America: case reports and
review. Clin Infect Dis 1992; 15:668 – 77.
3. Jayoussi R, Bialik V, Eyal A, Shehadah N, Etzione A. Pyomyositis caused
by vigorous exercise in a boy. Acta Paediatr 1995; 84:226 – 7.
4. Kinahan AM, Douglas MJ. Piriformis pyomyositis mimicking epidural
abscess in a parturient. Can J Anaesth 1995; 42:240 – 5.
5. Meehen J, Grose C, Soper RT, Kimura K. Pyomyositis in an adolescent
female athlete. J Pediatr Surg 1995; 30:127 – 8.
6. Miyaki H. Beitrage zur Kenntnis der sogenannten myositis infectiosa.
Mitteilungen aus den Grenzgebieten der Medizin und Chirugie 1904;
13:155 – 98.
7. Chen W. Sciatica due to piriformis pyomyositis. J Bone Joint Surg Am
1992; 74A:1546 – 8.
8. Gordon BA, Martinez S, Collins AJ. Pyomyositis: characteristics at CT
and MR imaging. Radiology 1995; 197:279 – 86.
9. Sarubbi FA, Gafford GD, Bishop DR. Gram-negative bacterial pyomyositis: unique case and review. Rev Infect Dis 1989; 11:789 – 92.
10. Rose HD, Franson TR, Sheth NK, Chusid MJ, Macher AM, Zeirdt CH.
Pseudomonas pneumonia associated with the use of a home whirlpool
spa. JAMA 1983; 250:2027 – 9.