Differentiating episodic ataxia type 2 from migraine: a case report

The periodic appearance of ostensibly functional symptoms is often misinterpreted as migrainous; notably, 50% of EA2 cases fulfil the International Headache Society criteria for migraine.3 In our patient, differentiating clues included identification of prolonged ataxic spells, exercise-induced attacks, and a lack of response to conventional migraine medications. The laboratory hallmark of GLUT1 deficiency is a low cerebrospinal fluid/blood glucose ratio [lesser than]0.4.4 Episodic ataxia type 2 is differentiated from other hereditary episodic ataxias by the age of onset, spell duration, interictal nystagmus, and genetic locus (Table).1 2 4 Table. Clinical features of various types of episodic ataxias (EA) Therapeutically, EA2 has a dramatic response to acetazolamide, with 50% to 75% of patients reporting improvement in episode severity and frequency at doses from 250 to 1000 mg daily.1 Dose escalation is often limited by side-effects of paraesthesia, nephrocalcinosis, fatigability and hyperhidrosis.1 5 If acetazolamide is not tolerated, the potassium channel blocker 4-aminopyridine may improve symptoms.