Hypocalcaemic Tetany and Seizures Secondary to Vitamin D Deficiency

A female adolescent presented with a generalised tonic-clonic seizure preceded by hands stiffness. She presented with a sudden history of being unresponsive with head deviation to right side, followed by up-rolling of eyes, and whole body shaking which self-terminated after five minutes. On examination, she was in postictal state, with inward clenching of both hands and fingers. The rest of her systemic examination was normal.

Laboratory results showed severe hypocalcaemia, hypomagnesaemia, hyperphosphatemia, elevated parathyroid hormone (PTH), and critically low vitamin D. ECG showed a prolonged QTc interval. Biochemical profile was consistent with secondary hyperparathyroidism. Severe vitamin D deficiency was the cause of her hypocalcaemia.

The patient was managed acutely with intravenous calcium gluconate and magnesium, followed by oral calcium and vitamin D supplementation.

This case highlights hypocalcaemia-induced seizures due to vitamin D deficiency in an adolescent, emphasising the importance of early recognition, biochemical assessment, and supplementation in at-risk populations.