Naeglaeria infection of the central nervous system, CT scan findings: A case series

The imaging findings in four cases of a rare infection of the central nervous system caused by amoebae, Naeglaeria fowleri are presented. Naeglaeria fowleri are pathogenic free-living amoebae. They cause primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system. The computed tomography brain findings in 3 (75%) of our cases of pan amoebic meningoencephalitis showed non-specific brain oedema; 2 (66%) of these cases also had moderate hydrocephalus and among that 1 (50%) case showed an old lacunar infarction in peri-ventricular region. In the remaining 1 (25%) case the scan was normal with no evidence of oedema or abnormal lesion. Out of three cases with diffuse brain oedema, postcontrast images showed abnormal meningeal enhancement throughout the brain parenchyma in 1 (33%) case. However, no definite focal enhancing lesion was noted. In the rest of the cases, no abnormal parenchymal or meningeal enhancement was seen on post-contrast images. The study was conducted in the Radiology Department of Aga Khan University Hospital, Karachi from July to December 2010.