CNS INFECTIONS WITH FREE-LIVING AMEBAS - NEUROIMAGING FINDINGS

OBJECTIVE. The purpose of this report is to describe the clinical hist ory, treatment, pa thology, and imaging in two cases of rare CNS infec tion caused by free-living amebas. The Naegleria fowleri and Acanthamo eba species cause primary amebic meningoencephalitis and granulomatous amebic encephalitis, respectively. We describe the neuroimaging findi ngs of a case involving a nonspecific cerebral edema pattern in primar y amebic meningoencephalitis and a case involving focal enhancing lesi ons in granulomatous amebic encephalitis. CONCLUSION. Primary amebic m eningoencephalitis and granulomatous amebic encephalitis have a grave prognosis and, although rare, should be considered in the differential diagnosis for patients who present with appropriate histories and ima ging findings, including nonspecific brain edema on CT in primary ameb ic meningoencephalitis and focal punctate enhancing lesions in the pos terior cranial fossa on T1-weighted MR imaging in granulomatous amebic encephalitis.