Prolonged Postictal Coma in Hemiplegic Migraine: A Case Report

Familial hemiplegic migraine (FHM) is a rare disease characterized by episodes of a prominent motor aura manifesting as hemiparesis and often accompanied by ataxia, nystagmus, seizures, and varying degrees of altered consciousness. Patients with FHM may also experience coma and subsequent respiratory failure requiring intubation. We describe a 57-year-old man with a past medical history of FHM type 1 (FHM1), genetically proven CACNA1A carrier, prior alcohol withdrawal seizure and type 2 diabetes who presented after a witnessed generalized tonic-clonic seizure. Since the onset of this seizure, the patient remained unresponsive for ~4 minutes but ultimately required intubation for airway protection. Exam revealed normal pupillary responses, no meningeal signs, a tonic downward gaze with ocular dipping, and mute plantar reflexes. MRI of the brain was without acute diffusional abnormality and EEG revealed generalized theta and delta without epileptiform discharges. This likely represented an exacerbation of his underlying hemiplegic migraine. He was started on dexamethasone, levetiracetam, and his acetazolamide was continued. He was extubated and remained encephalopathic for 4 days, but motor function and sensation were unimpaired. Lamotrigine was ultimately started and his levetiracetam discontinued. He had 3 prior episodes of unilateral weakness followed by loss of consciousness starting his teenage years. Two years prior he was admitted following a convulsion and loss of consciousness and required intubation for airway support. MRI of the brain was normal and CSF analysis revealed a lymphocytic pleocytosis. EEG was without epileptiform abnormalities but revealed generalized theta. He was extubated and placed on acetazolamide. Family history disclosed a paternal uncle with hemiplegic migraines. FHM exists in different subtypes, each with an autosomal dominant, channelopathy related pathophysiology. FMH1 is caused by a mutation in the Headache doi: 10.1111/head.13606 © 2019 American Headache Society Published by Wiley Periodicals, Inc. ISSN 0017-8748