Abnormal cerebral glucose metabolism in alternating hemiplegia of childhood.

Alternating hemiplegia of childhood (AHC) is a rare and intractable disorder of unknown cause. To determine cerebral neuronal function in five patients with AHC (two adults and three children), we analyzed brain glucose metabolism by positron emission tomography (PET) using 2-deoxy-2 [(18)F] fluoro-d-glucose (FDG), performed between hemiplegic attacks. Interictal FDG-PET revealed abnormal cerebral glucose metabolism; all patients showed low glucose metabolism in the frontal lobes with some laterality, and three had low glucose metabolism in the ipsilateral putamen. The adult patients also showed low glucose metabolism and mild atrophy in the cerebellum. Glucose metabolism in the brainstem was virtually normal for all patients. The areas of low glucose metabolism indicated local or regional neuronal damage, possible reflecting progressive neurological symptoms. AHC might therefore result from focal abnormal glucose metabolism in the brain occurring progressively or permanently, particularly in the frontal lobes and the cerebellum.