Cause:Bartonella (Rochalimaea) henselae(Nejm 1994;330:509; Ann IM 1993;118:331). Afipia felis,a closely related organism, may be the cause in some cases
Young cats, infected for a few weeks; transmit via bites, scratches, and fleas; 80% of cases are in pts under age 21 yr
Sx:Bite or scratch by kitten (90% have had by hx); 7- to 14-d incubation; then papule at site of scratch. Papule at site of infection; fever (<50%), adenopathy (40% of nodes suppurate)
Si:As above
Encephalopathy/encephalitis (10%), conjunctivitis, purpura (suppressed platelets), mesenteric adenitis, endocarditis (Ann IM 1996;125:646); hypercalcemia (Jama 1998;279:532)
in AIDS patients (Ann IM 1988;109:449) and otherwise immunocompromised hosts, disseminated disease; BACILLARY ANGIOMATOSIS (Nejm 1997;337:1876, 1888, 1916;1995;332:419, 424), which looks somewhat like Kaposi's sarcoma, cutaneous and deep tissue infections as well as osteolytic bone lesions; and PELIOSIS HEPATIS(Nejm 1992;327:1625; 1990;323:1573, 1581)
Lab:
CSF: Protein increased; occasionally mononuclear cells in 10%
Bact:Small pleomorphic gram-neg
Hem: Elevated ESR and white count with left shift; eosinophils elevated modestly
Path: Biopsy shows organism with Warthin-Starry and silver stains
Serol:Bartonella henselaetiters >1/64 (84% sens, 96% specif—Nejm 1993;329:8), from CDC, available commercially as well
Skin test:DHS pos in 30 d, homemade from ground-up nodes; no longer used due to AIDS and other viral risks
Rx:
None may be indicated in mild disease except aspiration of fluctuant nodes to decrease sx
of disease: