Case of pneumococcal meningoencephalitis with periodic synchronous discharge patterns on electroencephalogram

A 64-year-old man presented with high fever, deep coma, neck stiffness and decorticate rigidity on admission to our hospital. Laboratory findings revealed liver dysfunction, and serial brain computer tomography revealed a right cerebellar hematoma, a small hemorrhage in the left frontal lobe and ischemia of the left corona radiata. Electroencephalogram (EEG) showed periodic synchronous discharge (PSD) patterns on the first occasion, but these disappeared in later EEG. Based on the cerebrospinal fluid findings of increased total protein (1183 mg/dL), increased cells (71/mu L) and decreased glucose concentration (1 mg/dL), and the culture result of pure growth of Streptococcus pneumoniae, he was diagnosed as having pneumococcal meningoencephalitis. PSD patterns, though seldom found in bacterial meningoencephalitis, presented in this case probably due to severe infection of the central nervous system and hepatic encephalopathy. We report this case to emphasize that PSD can emerge on EEG in the early stage of pneumococcal meningoencephalitis.