[Alternating hemiplegia of childhood (AHC)]

Alternating hemiplegia of childhood (AHC) is a rare neurological disease of unknown aetiology characterized by recurrent paroxysmal attacks of side-alternating hemiplegias of variable duration associated with other paroxysmal dysfunctions. Paroxysmal attacks start in infants but neurological deficits become progressive with the age.

During the last 20 years 8 patients (5 boys, 3 girls) with AHC were followed. Mean age at the time of diagnosis was 2.75 years, age range 2-5 years; mean follow up period 13.9 years (range 1 month-20 years) The diagnosis was based on clinical history and neurological findings, completed by neurophysiological and neuroimaging methods (SPECT, PET), and results of psychological and biochemical findings. Paroxysmal phenomena (occulo-motor, tonic, choreo-athetotic, autonomic) appearing at the age of 4.1 +/- 2.2 months and followed by repeated attacks of hemiplegia (age onset 16.3 +/- 13.0 months) were the first symptoms. Progressive neurological impairment covering spasticity, dyskinetic syndrome, cerebellar ataxia and intellectual deficit was present in all cases, epileptic seizures in 7 out of 8 patients. On ictal SPECT/PET examination hypoperfusion/glucose hypometabolism were demonstrated above affected hemispheres including basal ganglia, both thalami and cerebellar hemispheres. Improvement of hemiparesis was illustrated by nocturnal videomonitoring.

AHC is a chronic disease with progressive neurological deficit. A flunarizine therapy has a favorable effect on frequency and severity of paroxysmal attacks, but does not prevent a progressive neurological impairment.