CAT SCRATCH DISEASE
Signs and Symptoms
The patient will manifest a regional lymphadenitis with the appearance of a small cutaneous lesion at the site of the inoculation following an incubation period ranging from several days to weeks. The patient will develop fever and flu-like symptoms, which typically resolve within three to six weeks. Vision varies widely, from normal acuity to finger counting, depending upon the severity of ocular manifestations. While patients may be visually asymptomatic, relative afferent pupil defects, dyschromatopsia and field loss may also be present.
Systemic signs may include hepatosplenic infection, encephalopathy, osteomyelitis and endocarditis. The most common ocular syndrome occurring from CSD is Parinaud's oculoglandular syndrome, manifesting as conjunctivitis, retrotarsal conjunctival granulations, regional preauricular and cervical lymphadenitis, and fever. Another common ocular manifestation associated with CSD is neuroretinitis, a combination of disc edema with stellate macular star exudates. Other fundus findings include peripapillary serous macular detachment, discrete foci of retinitis manifested as white retinal or choroidal lesions, vitritis, posterior uveitis, and submacular exudates. Anterior uveitis may also occur.1
Cat scratch disease is caused by the Gram-negative bacillus, Bartonella henselae and, to a lesser extent, Bartonella quintana. The organism is transmitted through the bite or scratch of an infected cat or kitten. Transmission through flea bites has not been reported. Following inoculation, there is an incubation period, which is followed by a period of self-limiting febrile illness with lymphadenopathy.
Proper diagnosis begins with clinical suspicion based upon ocular findings in association with an antecedent febrile illness. Testing for CSD involves obtaining ELISA Bartonella henselae titre. Titres for Bartonella quintana are appropriate as well. An alternate diagnostic modality is a polymerase chain reaction analysis of lymphadenopathy aspirate. This should be considered in a clinical situation in which CSD is strongly suspected and ELISA titers are negative, borderline or otherwise inconclusive.
In immunocompetent individuals, the course of CSD is self-limiting with a good prognosis. As such, medical treatment is generally unnecessary. However, cases with ocular involvement are generally recommended for treatment. The causative organism is susceptible to a number of antibiotics, including penicillins, cephalosporins, aminoglycosides, tetracyclines, macrolides, fluoroquinolones, and rifamicin. Doxycycline 100mg po bid for four weeks is a recommended therapy. This may be used alone or in combination with rifampin 300mg bid.24 Azithromycin is an acceptable substitute.5 In cases with vision loss, typically from neuroretinitis, oral prednisone is often employed with antimicrobial therapy.
Other reports in this section
Eyelids & Eyelashes | Conjunctiva & Sclera | Cornea
Uvea | Vitreous & Retina | Neuro-Ophthalmic Disease | Oculosystemic Disease
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