When Hormones Take Action: An unusual Cause of Seizures

Introduction: Hypoparathyroidism is a rare endocrine disease characterized by hypocalcaemia and hyperphosphatemia, in the setting of a low or inappropriately normal concentration of circulating parathyroid hormone (PTH). The clinical spectrum is broad, varying from mild disease with paraesthesia and muscle cramps to severe symptoms such as seizures. Soft tissue calcifications can occur and are typically seen in the central nervous system (basal ganglia) and kidney.

Case report: We present the case of a previously healthy fifteen-year-old boy with new-onset seizures over a two-month period and depressive symptoms. On examination he presented: slurred speech, resting and postural hand tremor and mild muscle tone increase in all limbs with cogwheel rigidity in the upper ones. Laboratory study revealed hypocalcaemia, hyperphosphatemia and decreased PTH serum concentration. Brain CT scan demonstrated extensive calcifications in the basal ganglia, subcortical white matter and thalamus. EEG showed no paroxystical activity. He was admitted considering the hypoparathyroidism, intracranial calcifications and structural epilepsy and started treatment with carbamazepine, calcium and cholecalciferol. Etiological investigation was inconclusive until now: magnesium, 25-hydroxyvitamin-D, renal and thyroid function were normal; negative anti-parathyroid antibodies; no evidence of nephrocalcinosis or nephrolithiasis on ultrasound. Two months after hospital discharge, the patient is asymptomatic, and his biochemical profile normalized.

Conclusions: Hypoparathyroidism is a rare endocrine disorder, however, phosphocalcic metabolism disorders should be included in the differential diagnosis of seizures. Most cases result from anterior neck surgery, followed by autoimmune disorders and rarely genetic and infiltrative disorders. Presently, treatment consists of calcium and activated vitamin D supplementation, but PTH replacement is under investigation.