Rasmussen encephalitis

Case contributed by Aravinda Perera

Presentation

Left-sided focal seizures, cognitive deterioration and episodic behavioral issues.

Patient Data

Age: 5 years
Gender: Female
MRI

White matter and cortical volume loss predominantly involving the right frontal lobe and right insular region. Prominent right cerebral convexity sulcal spaces. Dilated right Sylvian fissure.

Mild ex-vacuo dilatation of the temporal horn of the right lateral ventricle. The caliber of the ventricles elsewhere is normal.

No heterotopic grey matter or focal cortical dysplasia.

Reduced volume of the right midbrain and pons. Unilateral right-sided caudate loss of volume. Normal morphology of the corpus callosum and pituitary gland. Normal brainstem, cerebellum, and craniocervical junction.

Case Discussion

The overall appearance of unilateral hemispheric cortical atrophy on MRI is suggestive of Rasmussen encephalitis.

Electroencephalography (EEG) showed focal slowing and interictal discharges in the right temporal area. The patient was initially treated for presumed Rasmussen encephalitis with anticonvulsants, a monoclonal antibody, and intravenous immunoglobulin.

A right-sided hemispherectomy was later performed due to ongoing seizures refractory to medical therapy. Histological analysis of resected brain tissue confirmed a diagnosis of Rasmussen encephalitis.

It should be noted that histological review also revealed mesial temporal sclerosis of the right hippocampus.

The patient experienced no further seizures following the right-sided hemispherectomy.

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