Eleven-Year-Old Girl With Bilateral Leg Pain: A Case Report on Recognizing Hypoparathyroidism in Pediatric Practice

Hypoparathyroidism is a rare disorder that presents with a low total serum or ionized calcium, characterized by insufficient release of parathyroid hormone (PTH) from the parathyroid glands to maintain serum calcium. Patients with hypoparathyroidism may present with acute symptoms of muscle cramps, paresthesia, numbness, tetany, muscle pain in the calves, and carpopedal spasms. This case study reports an 11-year-old girl with 3 weeks of bilateral, painful leg, occasional leg paresthesia, and fatigue. Initial investigations in the emergency department revealed an elevated creatinine kinase of 995 U/L and low total calcium of <1.25 mmol/L. On further workup, she was found to have a low ionized calcium of 0.56 mmol/L, hyperphosphatemia of 2.03 mmol/L, and inappropriately low PTH of <0.5 pmol/L. Interestingly, Chvostek's sign was negative, and her neuromuscular physical exam was normal. Her ECG, however, displayed normal sinus rhythm with a prolonged QT interval. She was treated with intravenous calcium gluconate as she had an acute gastroenteritis concurrently, then transitioned to oral active vitamin D (alfacalcidol) and oral calcium and discharged home. Genetic testing for inherited causes of hypoparathyroidism were found to be negative and the diagnosis of idiopathic hypoparathyroidism was made. In children with acute myalgias or unexplained creatinine kinase elevation, calcium and PTH should be measured. Early recognition and correction of hypocalcemia can prevent long term complications such as irreversible basal ganglia calcifications, papilledema, lenticular cataracts, and cardiac complication.