Parathyroid Storm Secondary to a Parathyroid Adenoma Presenting With Recurrent Generalised Tonic-Clonic Seizures and Refractory Hypercalcaemia: A Case Report

Parathyroid storm is a rare, life-threatening manifestation of primary hyperparathyroidism characterised by severe hypercalcaemia and acute multisystem deterioration.We report a 70-year-old woman with known primary hyperparathyroidism who presented with progressive weakness, confusion and reduced mobility and was found to have a corrected serum calcium concentration of 4.14 mmol/L.Despite aggressive intravenous hydration, she developed recurrent generalised tonic-clonic seizures, hypoventilation and reduced consciousness, requiring intubation and intensive care admission.Electroencephalography demonstrated severe diffuse cerebral dysfunction consistent with metabolic encephalopathy, while cerebrospinal fluid studies were unremarkable.Four-dimensional computed tomography of the neck identified a 1.8 cm right-sided parathyroid lesion.Hypercalcaemia remained difficult to control despite multimodal medical therapy, including pamidronate, calcitonin, cinacalcet and denosumab, with recurrent rebound hypercalcaemia.Urgent parathyroidectomy resulted in sustained normalisation of serum calcium and cessation of seizure activity, and histopathology confirmed a benign parathyroid adenoma.This case highlights the severe neurological complications of parathyroid storm and the importance of early multidisciplinary consideration of definitive surgery when hypercalcaemia remains refractory to intensive medical therapy.