Cat scratch fever pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
The causative organism was first thought to be Afipia felis, but this was disproved by immunological studies demonstrating that cat scratch fever patients developed antibodies to two other organisms, Bartonella henselae (B. henselae) and Bartonella clarridgeiae, which are rod-shaped Gram-negative bacteria.
Pathophysiology
Transmission
Kittens are more likely to carry the bacteria in their blood, and may therefore be more likely to transmit the disease rather than adult cats. However, the results of experimental studies showed that fleas serve as a vector for transmission of B. henselae among cats,[1] and that viable B. henselae are excreted in the feces of Ctenocephalides felis, the cat flea.[2] Another study showed that cats could be infected with B. henselae through intradermal inoculation using flea feces containing B. henselae.[3] As a consequence, it is believed that a likely means of transmission of B. henselae from cats to humans may be inoculation with flea feces containing B. henselae through a contaminated cat scratch wound or across a mucosal surface. Although Bartonella DNA has been reported in ticks, there is no evidence that CSD can be transmitted by tick bites.[4]
Pathology
The primary cutaneous lesion consists of a red papule at site of inoculation, 1–2 weeks after contact, which may become pustular or crusted, which is accompanied by enlargement of regional – usually the cervical and axiallary – lymph nodes. Under the microscope, the skin lesion demonstrates a circumscribed focus of necrosis, surround by histiocytes, often accompanied by multinucleated giant cells, lymphocytes, and eosinophils. The regional lymph nodes demonstrate follicular hyperplasia with central stellate necrosis with neutrophils, surrounded by palisading histiocytes (suppurative granulomas) and sinuses packed with monocytoid B cells, usually without perifollicular and intrafollicular epithelioid cells
The Warthin–Starry stain is used to confirm the presence of B. henselæ.
Atypical cat scratch disease takes several different forms depending on organ systems involved. Atypical forms of disease are becoming increasingly recognized in clinical practice.
Parinaud's oculoglandular syndrome is a granulomatous conjunctivitis with concurrent swelling of the lymph node near the ear.
Optic neuritis, involvement of the retina, and neuropathy can also occur.
Bacillary angiomatosis is caused by Bartonella henselae, the causative organism of cat scratch disease. It is primarily a vascular skin lesion that may extend to bone or be present in other areas of the body. In the typical scenario, the patient has HIV or another cause of severe immune dysfunction.
Bacillary peliosis is a condition that most-often affects patients with HIV and other conditions causing severe immune compromise. The liver and spleen are primarily affected, with findings of blood-filled cystic spaces on pathology [5]
References
- ↑ Chomel BB; Kasten RW; Floyd-Hawkins K; et al. (1996). "Experimental transmission of Bartonella henselae by the cat flea". J. Clin. Microbiol. 34 (8): 1952–6. PMC 229161. PMID 8818889. Unknown parameter
|month=ignored (help); Unknown parameter|author-separator=ignored (help) - ↑ Higgins JA, Radulovic S, Jaworski DC, Azad AF (1996). "Acquisition of the cat scratch disease agent Bartonella henselae by cat fleas (Siphonaptera:Pulicidae)". J. Med. Entomol. 33 (3): 490–5. PMID 8667399. Unknown parameter
|month=ignored (help) - ↑ Foil L; Andress E; Freeland RL; et al. (1998). "Experimental infection of domestic cats with Bartonella henselae by inoculation of Ctenocephalides felis (Siphonaptera: Pulicidae) feces". J. Med. Entomol. 35 (5): 625–8. PMID 9775583. Unknown parameter
|month=ignored (help); Unknown parameter|author-separator=ignored (help) - ↑ Telford SR III, Wormser GP (2010). "Bartonella spp. transmission by ticks not established". Emerg Infect Dis. 16 (3): 379–84. doi:10.3201/eid1603.090443. PMID 20202410. Unknown parameter
|month=ignored (help) - ↑ Perkocha LA; Geaghan SM; Yen TS; et al. (1990). "Clinical and pathological features of bacillary peliosis hepatis in association with human immunodeficiency virus infection". N. Engl. J. Med. 323 (23): 1581–6. doi:10.1056/NEJM199012063232302. PMID 2233946. Unknown parameter
|month=ignored (help); Unknown parameter|author-separator=ignored (help)