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Blue indicates areas of high risk.
Cat-Scratch Disease
BACKGROUND
Cat-scratch disease (CSD), caused by the gram-negative coccobacillus Bartonella henselae, is a zoonosis that usually manifests in children as subacute regional lymphadenitis. Cats are the natural reservoir for
B henselae and in developing countries up to 70% of urban domestic cats and 90% of stray cats carry the organism. The cat flea, Ctenocephalides felis, transmits
B henselae between cats. The distribution of CSD is worldwide and human disease occurs more frequently in fall and winter months. Bartonella clarridgeiae has been identified as the culprit in isolated cases of CSD.
PATHOPHYSIOLOGY
Most cats that carry B henselae demonstrate no signs of infection. Inoculation
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Serologic testing is most simple and helpful.
B henselae is difficult to culture. In selected cases, excision of an involved node is useful for histopathologic examination. Fine-needle aspira- tion biopsy is less invasive and may be preferred if feasible. Conventional stains can demonstrate granulomas and stellate necrosis, and silver stains can detect suggestive bacillary forms. 77
CAT-SCRATCh DISEASE
IMAGE 1A–1C
Cat-scratch disease with a right epitroclear lymphadenopathy in a 10-year-old child after
2 weeks of progressive growth of a mass on his arm (Image A). He played with 2 cats at home.
IgG serology for B henselae during treatment was highly positive. Ultrasound identified
2 enlarged lymph nodes (Images 1B, 1C). Courtesy: Javier Santisteban-Ponce.
Immunohistochemistry may reveal
B henselae in tissues that surround necrotic areas. Advanced techniques in molecular biology (eg, polymerase chain reaction analysis) exist for diag- nosis of CSD, though are expensive and less available.
TREATMENT AND PREVENTION
If follow-up is possible, then some immunocompetent hosts with typi- cal CSD may be managed expectantly.
Without intervention, CSD