Clinical Reasoning: A middle-aged man with episodes of gait imbalance and a newly found genetic mutation

Abstract

A 47-year-old right-handed man, with no history of alcohol use, presented with episodic unsteadiness that began in his early 20s. During the episodes, which last several hours, he is unable to walk steadily and has poor control of his limbs. These attacks are often brought on by emotional stress and occurred 1 to 2 times per month into his 30s. There is no association with headache or head movement, no diplopia, tinnitus, or hearing loss. His earlier evaluation included a brain MRI and routine EEG, which were normal. Though his diagnosis was unknown, he was given a trial of acetazolamide at age 38, and became attack-free on the medication. ### Questions for consideration: 1. What is the differential diagnosis for paroxysmal episodes of neurologic dysfunction based on the time course and age at onset? 2. How can medication responsiveness and examination findings be helpful? GO TO SECTION 2 In this patient, the likely etiologies for paroxysmal neurologic events are seizures, migraine, vestibular syndromes, and paroxysmal movement disorders. Pure ataxia as seizure semiology has not been described: cerebellar cortex is not known to be epileptogenic. Vertiginous partial seizures may be localized to the posterior part of superior temporal neocortex, are rare, and typically seen in conjunction with other temporal lobe localizing symptoms (auditory, olfactory). Postictal state of complex partial or generalized seizures can result in gait unsteadiness associated with fatigue and confusion and gradual improvement. In migraine, paroxysmal neurologic symptoms may occur without headache. Classified as typical aura without headache, the aura must include visual or sensory symptoms, and last less than …