Fulminant subacute sclerosing panencephalitis presenting with acute ataxia and hemiparesis in a 15-year-old boy.

Background: Subacute sclerosing panencephalitis (SSPE) is a delayed and fatal manifestation of measles infection. Fulminant SSPE is a rare presentation in which the disease progresses to death over a period of 6 months. The clinical features are atypical and can be misleading.

Case Report: We report herein a teenage boy who presented with acute-onset gait ataxia followed by right hemiparesis that evolved over 1 month, with left-hemispheric, delta-range slowing on the electroencephalogram (EEG). Magnetic resonance imaging disclosed multiple white-matter hyperintensities, suggesting a diagnosis of acute disseminated encephalomyelitis. He received intravenous steroids, and within 4 days of hospital admission he developed unilateral slow myoclonic jerks. Repeat EEG revealed Rademecker complexes, pathognomonic of SSPE, and an elevated titer of IgG antimeasles antibodies was detected in his cerebrospinal fluid. The disease progressed rapidly and the patient succumbed within 15 days of hospitalization. The diagnosis of SSPE was confirmed by autopsy.

Conclusions: This case illustrates the difficulty of recognizing fulminant SSPE when it manifests with asymmetric clinical and EEG abnormalities.