Case Presentation: A 57-year-old man with IgA vasculitis on maintenance rituximab, cyclophosphamide and prednisone presented with 2 months low-grade fevers, fatigue, 60 pounds weight loss, and bilateral visual abnormalities. Family cared for his 7 cats and new kittens while he presented to our hospital. Ophthalmological exam was notable for bilateral neuroretinitis. MRI of the brain revealed multiple abnormalities of the basal ganglia and brainstem, suggesting multifocal infarcts or atypical infection. Repeated CSF examination demonstrated mild leukocytosis but negative cultures and cytology. Inflammatory markers (ESR/CRP) were elevated. CT chest/abdomen/pelvis demonstrated no evidence of infection or malignancy. Transesophageal echocardiogram was negative. Repeat blood cultures and numerous serologic testing for infection was negative. Vitrectomy cytology and broad-range PCR was negative. We considered empiric treatment for presumed vasculitis, but could not rule out opportunistic infection. Ultimately a brain biopsy was performed, with PCR positive for Bartonella henselae. The patient was treated with 6 weeks of oral rifampin and doxycycline with IV ceftriaxone.
Discussion: This case highlights the difficulties in diagnosing atypical presentations of Bartonella infection, due to varying clinical presentation, lack of classical imaging findings, and low sensitivity of diagnostic testing. Our patient presented with ophthalmological and encephalopathic changes without the classical lymphadenopathy of cat scratch disease. While our patient’s ocular manifestations can be seen in Bartonella infection, the findings were also consistent with possible fungal, viral, or other bacterial infection, ocular lymphoma or leukemia, or CNS vasculitis. The structural change seen on our patient’s brain MRI are also nondiagnostic. Our patient also had multiple false negative tests for Bartonella including negative IFA test on serum, negative IFA on CSF, negative PCR on CSF, and negative PCR on intraocular fluid. The immunosuppressed state of our patient with hypogammaglobulinemia likely decreased the already low sensitivities of serological testing. The diagnosis was ultimately made by broad-range PCR of brain tissue.
Conclusions: Atypical cases of Bartonella infection are difficult to diagnose due to the wide array of symptoms attributed to the disease and often inadequately sensitive diagnostic testing. Bartonella must remain on the differential in immunosuppressed patients with cat contact, even in the presence of negative diagnostic testing. In this case, a brain biopsy with PCR of brain tissue was required for the diagnosis.