Abstracts

Rationale: To describe the clinical characteristics of 3 cases of AHC, including novel treatment. Methods: We report three patients with AHC: a rare disorder affecting about 1:1,000,000 where the patient suffers from episodes of hemiplegia that moves from one side of the body to the other, resulting in hypofunction of one side of the body. The onset of the weakness usually occurs in the first few months of life. The episodes of hemiplegia might be triggered by various stimuli, such as warm baths, movement and psychological stress or emotions. Occasional attacks are complicated by respiratory difficulties and dysphagia. The attacks vary in frequency between several monthly or weekly. The duration varies from minutes to hours, even days. The only factor that may abort the episodes is sleep. Movement disorder such as dystonia can also accompany the hemiplegic attacks in 2/3 cases. Intellectual impairment and epilepsy have been reported in these patients. However, the onset of seizures is usually in the age range between 3 to 4 years. The management of these cases is challenging. The only drug with some efficacy is flunarizine and AEDs for seizure control. A trial of gamma-hydroxy butyrate (GHB) in N=1 study had some efficacy and lateralised EEG changes contralateral to the side of hemiplegia, reversing with GHB. Results: In 2/3 cases the disorder extended into adulthood necessitating a name change: AHCA for the same genotype. The mutation found to be associated with AHC is the ATP1A3 gene in 3/3 cases, reported in a majority of AHC patients, with some familial cases. Conclusions: AHCA is very uncommon, likely underdiagnosed clinically but with a high index of suspicion for early diagnosis and appropriate therapy, may ameliorate outcome and long-term prognosis in a larger RCT study.