Acute febrile cerebrovasculitis. A non-spotted fever group rickettsial disease.

In December 1985, a patient was seen with an illness that was clinically compatible with the recently described clinical syndrome of acute febrile cerebrovasculitis, including fever, headache, altered mentation, multifocal neurologic signs, and cerebrospinal fluid pleocytosis. An extensive medical evaluation failed to reveal a cause, until, retrospectively, she was shown to have antibodies to Rickettsia typhi. Detailed serologic analysis with enzyme immunoassays and protein immunoblots indicated that she was infected with a non-spotted fever group Rickettsia, most likely either R typhi or Rickettsia canada. Serum samples from a mouse trapped at her home contained antibody only to R canada. Evaluation of patients with acute febrile cerebrovasculitis in the future should include rickettsial blood cultures to attempt specific identification of the species involved.