Rasmussen encephalitis

Case contributed by Ivan Turkalj
Diagnosis almost certain


A male, mentally disabled, patient admitted to the emergency ward due to longstanding intractable seizures. He had been suffering epilepsy since he was 10 with progressive cognitive loss and mild right-sided hemiparesis.

Patient Data

Age: 35 years
Gender: Male

CT Brain


Severe dilatation of the left lateral ventricle accompanied with ipsilateral cerebral hemisphere atrophy. No evidence of intracranial hemorrhage, nor recent brain ischemia.  

Case Discussion

The clinical and imaging findings are consistent with the late stage of Rasmussen encephalitis, which is a rare disorder of the central nervous system characterized by chronic encephalitis of one hemisphere of the brain. Although the exact cause of this disorder is not known, viral or post-viral etiology have been postulated.

Differential diagnosis includes Dyke-Davidoff-Masson syndrome, which is less likely in the present case due to absence of compensatory skull vault thickening and ipsilateral falcine displacement.

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