Severe hypocalcaemia episodes in a patient of primary hypoparathyroidism precipitated by underlying stress due to haemophagocytic lymphohistiocytosis (HLH) secondary to pulmonary tuberculosis

Abstract

A man in his 20s who had previously experienced multiple episodes of transient loss of consciousness, majorly attributable to the seizures, presented with a 1-month history of increased seizure frequency, high-grade fever and weight loss. Clinically, he had postural instability, bradykinesia and symmetrical cogwheel rigidity. His investigations revealed hypocalcaemia, hyperphosphataemia, inappropriately normal intact parathyroid hormone, metabolic alkalosis, normomagnesemic magnesium depletion, and increased plasma renin activity and serum aldosterone concentration. CT scan of the brain revealed symmetrical calcification of the basal ganglia. The patient had primary hypoparathyroidism (HP). A similar presentation of his brother indicated a genetic cause, most likely autosomal dominant hypocalcaemia with Bartter’s syndrome type 5. The patient’s fever was caused by underlying haemophagocytic lymphohistiocytosis secondary to pulmonary tuberculosis, which triggered acute episodes of hypocalcaemia. This case represents a complex interplay of a multifaceted relationship between primary HP, vitamin D deficiency and an acute stressor.