Lack of response to vitamin D therapy in a patient with hypoparathyroidism under anticonvulsant drugs

The case is presented of a 16-year-old boy suffering from idiopathic hypoparathyroidism with severe seizures who erroneously and unsuccessfully had received anticonvulsive therapy for 12 years. When the correct diagnosis was made, treatment with massive doses of vitamin D₂ was started. However, this treatment became effective only after the anticonvulsive therapy was discontinued; the serum calcium, phosphorus and the plasma 25-hydroxycholecalciferol returned to normal values, and the seizures stopped.