Crises épileptiques révélant des anomalies du métabolisme phosphocalcique

Hypocalcemia due to hypoparathyroidism produces a broad spectrum of clinical manifestations, but overt symptoms may be sparse. One unusual presentation is onset or aggravation of epilepsy in adolescence revealing hypoparathyroidism. This situation can lead to delayed diagnosis, with inefficacity of the antiepileptic drugs. We report five cases of adolescence-onset epilepsy with unsuccessful antiepileptic therapy, even with gradually increasing dose. Physical examination revealed signs of hypocalcemia, confirmed biologically. Full testing disclosed the origin of the seizures: hypoparathyroidism in three patients and pseudohypoparathyroidism in the other two. In four of five patients, computed tomography showed calcification of the basal ganglia, defining Fahr's syndrome. The patients were treated with oral calcium and active vitamin D (1-alphahydroxy vitamin D3). Seizure frequency progressively decreased and serum calcium levels returned to normal. These cases illustrate the importance of the physical examination and of routine serum calcium assay in patients with new-onset epileptic seizures in order to detect hypocalcemia secondary to hypoparathyroidism.