Stone, paper… seizure? A case report of hypocalcemic seizures worsened by anti-seizure medications.

Abstract

Refractory seizures in the emergency department (ED) may result from overlooked metabolic causes. Primary hypoparathyroidism is a rare but treatable etiology, sometimes associated with Fahr's syndrome. We report a 27-year-old man with a known seizure disorder presenting with multiple daily generalized tonic-clonic seizures unresponsive to polytherapy. Examination revealed positive Trousseau's and Chvostek's signs. Laboratory tests demonstrated severe hypocalcemia, hyperphosphatemia, and markedly reduced intact parathyroid hormone, consistent with primary hypoparathyroidism. Non-contrast CT head revealed bilateral basal ganglia calcifications. Recent initiation of phenytoin and carbamazepine-potent enzyme inducers-aggravated hypocalcemia by accelerating vitamin D metabolism. The patient was treated with intravenous calcium gluconate, magnesium sulfate, and switched to levetiracetam. Calcium normalized within 24 h, and seizures resolved. This case highlights the importance of considering metabolic disturbances in ED patients with worsening seizures despite appropriate anti-seizure therapy, and the potential for anti-seizure medications to exacerbate underlying conditions.