SUCCESSFUL TREATMENT OF TWO CASES OF ALTERNATING HEMIPLEGIA WITH ACETAZOLAMIDE

Objectives: To describe the response to acetazolamide of one patient with classical alternating hemiplegia and one patient with a variant of alternating hemiplegia.

Methods: Case descriptions.

Results: Case 1. This middle-aged adult woman presented in infancy with classical attacks of alternating hemiplegia. Her clinical course has been typical leaving her mentally handicapped and dependent. Attacks have been well documented by her mother and caretakers and have continued throughout her entire life with no remissions at a rate of 3–4/week. Flunarizine, phenytoin and phenobarbital were ineffective. Acetazolamide 500mg/day for the past 5 months has been associated with a striking reduction in attacks to once every 2 weeks. Case 2. This 14 year old girl began daily attacks at age 4 months (longest event-free interval 14 days). Consciousness was preserved during the attacks that consisted of tonic, conjugate, horizontal eye deviation for 5–45 minutes followed by irritability until she slept. From age 5 years her attacks worsened with eye deviation invariably followed by painful limb and back stiffening (unilateral or bilateral) for up to several hours (see video) with partial response to oral diazepam. A few minutes of sleep would completely arrest the attack. At 14 years stable spastic diplegia prevented walking, dystonic hand posturing was prominent but she could read at age level. Video EEG of events was unrevealing. Carbamazepine, phenytoin, clobazam and flunarazine were ineffective. With daily acetazolamide (187.5mg/day) her attacks have stopped for 18 months. Unfortunately her neurological function has not improved.

Conclusion: The response of our two patients suggests that acetazolamide may be very effective for the hemiplegic attacks of classical and variant childhood onset alternating hemiplegia. By analogy with other disorders that respond to acetazolamide, alternating hemiplegia may be a channelopathy.