TONIC SEIZURES IN A PATIENT WITH BRAIN-STEM DEMYELINATION - MRI STUDYOF BRAIN AND SPINAL-CORD

Tonic seizures are a poorly understood manifestation of demyelinating disease, first reported in 4 patients with multiple sclerosis. We desc ribe a patient with tonic extension of the left limbs caused by a righ t-sided brainstem lesion as the first manifestation of demyelinating d isease. A 19-year-old man was referred with a 4-month history of spont aneous attacks of mild paresthesias of the left arm and leg, followed by 15-45 s of rigid extension of the left limbs, occurring up to 25 ti mes per day. Two months after onset, an MRI scan revealed areas of T-2 abnormality in the lateral right cerebral peduncle and deep frontal w hite matter. The EEG was normal, including during hyperventilation whi ch induced a typical episode. All attacks were successfully suppressed by carbamazepine, phenytoin, and valproate monotherapy. Serologic tes ting for toxoplasmosis, cytomegalovirus, Epstein-Barr virus, Lyme dise ase, and HIV was negative. Cerebrospinal fluid oligoclonal bands were absent but cerebrospinal fluid immunoglobulin G was mildly elevated (4 .2 mg/dl). Over the next 30 months, serial MRIs revealed a normal spin al cord and persistence of the midbrain lesion, with resolution of som e of the white matter lesions but reappearance of others. At 46 months , the midbrain lesion resolved on MRI, and the spasms no longer occurr ed spontaneously, nor could they be elicited by hyperventilation. Whil e two previous reports have shown internal capsule lesions to underlie the tonic spasms in demyelinating disease, this is the first report i n which a brainstem lesion has been causative.