History and clinical findings: A 39-year-old HIV positive patient developed myalgia, headache and cough 4 weeks after a tick bite. His temperature was 37.4 degrees C and a circular pale erythema was noted over the left lower leg.
Investigations: C-reactive protein was raised to 120 mg/l, white blood cell count was 5860/microliter, CD4-lymphocyte count 250/microliter. The chest radiogram showed pneumonitic infiltration in the left lower lobe. There were IgM antibodies against Borrelia burgdorferi.
Treatment and course: Left lower lobe pneumonia and chronic erythema migrans were diagnosed and he was given oral azithromycin (500 mg on the first day and 250 mg for 4 days). The pneumonia cleared up, but 2 weeks later he developed symptoms of meningitis (496 cells per microliter, 87% lymphocytes, positive Borrelia burgdorferi antibody titer), which quickly and lastingly responded to ceftriaxon (2 g daily by brief infusion for 14 days).
Conclusion: This immune-compromised HIV-infected patient developed disseminated borreliosis with CNS involvement 2 weeks after the occurrence of chronic erythema migrans. The initial treatment of the latter with azithromycin was unable to prevent the meningitis. It is unlikely that there was a causal connection between the borreliosis and the pneumonia.