Endocrine Abstracts

Introduction: Hypocalcaemia is a frequent complication after thyroid and parathyroid surgery. We report a case of tetany occurred in a patient with normal serum levels of calcium, magnesium and phosphate after parathyroidectomy for hyperparathyroidism.

Case History: 55 year old Caucasian male was referred by general physician with three month history of fatigue, loss of appetite, intermittent constipation and abdominal pain. Systemic examination unremarkable. His investigations were keeping with primary hyperparathyroidism with adjusted ca raised at 3.3 mmol/l. He also had vitamin D deficiency which was treated with loading dose of oral cholecalciferol. A right inferior parathyroid adenoma was identified on concordant imaging and isotope scan. He underwent parathyroidectomy in the local hospital. He presented to accident emergency twice within days of surgery with severe spasms of the hands and legs. On clinical examination, trousseau sign was positive.

Investigations and results: His calcium levels were normal at 2.3 mmol/l. Magnesium and phosphate levels were also normal at 0.82 mmol/l and 0.96 mmol/l respectively.

Conclusion: Our patient presented with usual symptoms and signs of hypocalcemia but normal serum levels of calcium and magnesium. We propose that our case represents normocalcemic tetany, which has been rarely reported in post-parathyroidectomy patients. The likely underlying mechanism appears to be neuronal excitability due to sudden reduction in serum calcium levels after long standing marked hypercalcemia.