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cat scratch disease

Inoculation of Bartonella henselae from the scratch or bite of an infected cat, generally a infected kitten. Bartonella henselae may also be transmitted by fleas of kitten. Kitten may be bacteremic with B henselae for months while appearing healthy. Cases after exposure to dogs & monkeys have been reported. The disease is more common in children. Pathology: 1) granulomas surrounding stellate microabscesses 2) skin lesions are designated bacillary angiomatosis 3) liver & spleen lesions are designated bacillary peliosis Clinical manifestations: 1) malaise (30%) 2) headaches (13%) 3) fever 4) splenomegaly (12%) 5) conjunctivitis (5%) 6) scratch with papule or vesicle 4-6 days (3-10 days) post exposure - often gone when patient presents to physician 7) regional, painful lymphadenopathy with overlying erythema a) 1-8 weeks after papule appearance b) 80% of nodes involve upper extremities, neck & head c) preauricular lymphadenitis 8) 80% of patients are < 21 years of age & have self-limited regional disease 9) episodes frequently resolve spontaneously in 2-4 months 10) 2% of patients suffer complications a) bacteremia d) involvement of liver, spleen, lung, bone, CNS, retina conjunctiva, skin e) encephalitis, seizures [6] c) immunocompromised hosts especially susceptible Laboratory: 1) skin testing with antigen 2) cultures a) blood culture or culture of skin lesions b) 9-15 days required for growth 3) Warthin-Starry silver stain 4) serology - Bartonella henselae antibody in serum - indirect fluorescent antibody tests 5) electron microscopy for organisms 6) WBC generally within normal limits 7) erythrocyte sedimentation rate (ESR) commonly elevated Differential diagnosis: 1) regional lymphadenopathy - suppurative bacterial lymphadenitis - atypical mycobacteria - sporotrichosis - tularemia - toxoplasmosis - infectious mononucleosis - tumors - sarcoidosis - lymphogranuloma venereum - coccidioidomycosis 2) other infections associated with cats - Capnocytophaga spp. (bite/infection) - Microsporum canis (dermatophytosis) - Toxocara cata (larva migrans) - Dirofilaria repens (subcutaneous nodules) Management: 1) generally symptomatic, but self-limited 2) pharmacologic agents a) azithromycin b) rifampin c) ciprofloxacin d) trimethoprim/sulfamethoxazole e) clarithromycin f) doxycycline g) erythromycin (drug of choice for bacillary angiomatosis) 3) relapses may occur 4) surgical drainage of suppurative node may be indicated

Related

Bartonella henselae (Rochalimaea henselae)

General

bacterial infection

References

  1. DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 872-73
  2. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1126-27
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 19. American College of Physicians, Philadelphia 1998, 2012, 2021
  4. Color Atlas & Synopsis of Clinical Dermatology, Common & Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 652-54
  5. Stevens DL, Bisno AL, Chambers HF et al Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis. 2005 Nov 15;41(10):1373-406. Epub 2005 Oct 14. PMID: 16231249
  6. Wyllie E, Rincon SP, Pierce VM Case 16-2015 - A 9-Year-Old Girl with Loss of Consciousness and Seizures. N Engl J Med 2015; 372:2050-2058. May 21, 2015 PMID: 25992750 http://www.nejm.org/doi/full/10.1056/NEJMcpc1501149