Abstract

The involvement of the cerebellum in Legionnaires’ disease has been noted in occasional case reports, but there have been no reviews on this subject to date. We report a previously healthy patient who contracted Legionella pneumonia and developed profound cerebellar dysfunction during his illness. He was treated with antibiotics with improvement of his pneumonia, but his cerebellar symptoms persisted. We review 29 case reports of cerebellar dysfunction in Legionnaires’ disease and summarize the clinical course, cultures, cerebrospinal fluid analyses, and neuroimaging. Finally, possible methods of pathogenicity are discussed including data regarding direct bacterial invasion, toxin production, and immune-mediated mechanisms.

Legionnaires’ disease was initially described as a pneumonic illness among delegates to the 1976 American Legion convention in Philadelphia. ^1,2 Although respiratory symptoms dominate the clinical picture, early investigators also recognized systemic involvement, including the kidneys and the central nervous system. ^3–5 Encephalopathy, manifested by confusion or even coma, is the most common neurologic symptom; the severity is often out of proportion to metabolic derangements, suggesting a specific effect of the legionnaires’ bacterium on the central nervous system. ^4,6 Although the neurologic symptoms usually resolve with time, some patients have persistent deficits, especially in cerebellar function. ⁶ A case of persistent cerebellar dysfunction that occurred during treatment of Legionellapneumonia is presented, followed by a review of the literature for reports of cerebellar involvement in legionellosis. Finally, the neuropathology of Legionnaires’ disease is examined for possible causes of neurologic dysfunction in this infection.