A case of Balamuthia mandrillaris meningoencephalitis

Balamuthia mandrillaris is a newly described pathogen that causes granuloma tous amebic encephalitis, an extremely rare clinical entity that usually oc curs in immunosuppressed individuals. We report a case of pathologically pr oven Balamuthia encephalitis with unusual laboratory and radiologic finding s. A 52-year-old woman with idiopathic seizures and a 2-year history of chr onic neutropenia of unknown cause had a subacute illness with progressive l ethargy, headaches, and coma and died 3 months after the onset of symptoms. Cerebrospinal fluid (CSF) glucose concentrations were extremely low or unm easurable, a feature not previously described (to our knowledge). Cranial m agnetic resonance imaging scans showed a single large temporal lobe nodule, followed 6 weeks later by the appearance of 18 ring-enhancing lesions in t he cerebral hemispheres that disappeared after treatment with antibiotics a nd high-dose corticosteroids. The initial brain biopsy specimen and analysi s of CSF samples did not demonstate amebae, but a second biopsy specimen an d the postmortem pathologic examination showed Balamuthia trophozoites surr ounded by widespread granulomatous inflammation and vasculitis. The patient 's neutropenia and antibiotic use may have caused susceptibility to this or ganism. Amebic meningoencephalitis should be considered in cases of subacut e meningoencephalitis with greatly depressed CSF glucose concentrations and multiple nodular lesions on cerebral imaging.