Acetazolamide-responsive episodic ataxia syndrome.

We studied a kindred with an acetazolamide-responsive, episodic ataxia syndrome. Affected members experienced paroxysmal attacks of ataxia that were precipitated by exertion or stress. All but one young patient had additional neurologic symptoms that included paresthesia, weakness, headache, tinnitus, vertigo, and myotonia. All symptoms were prevented by acetazolamide. Between attacks, serum pyruvate and lactate levels and urinary amino acids were normal, but electroencephalograms showed paroxysmal, high-amplitude, slow and sharp activity. Serum K+ was normal during attacks. The metabolic abnormality seems to affect the cerebellum and brainstem and may involve peripheral nerve and muscle.