NIV Congres

Introduction: Hypoparathyroidism usually presents with symptoms of hypocalcemia. Idiopathic hypoparahyroidism is diagnosed when all secondary causes are excluded. We describe a patient with a life-threatening event caused by idiopathic hypoparathyroidism.

Case: A 17-year old girl, with no medical history was found unconscious at the bottom of the swimming pool during her weekly water polo training. At the side of the swimming pool she was blue, had spasms and had a snoring breath. A normal regular pulse was felt. After arrival of the ambulance, she woke up and was admitted to our hospital. Trauma screening at the emergency department did not reveal physical abnormalities. An electrocardiogram showed a normal sinus rhythm with a prolonged QT-c time of 550 ms. Laboratory tests revealed a severe hypocalcemia of 0.94 mmol/L (albumin 43 g/L). The collapse was interpreted as probably a seizure caused by the severe hypocalcemia.

The internist was consulted for further analysis and treatment of the hypocalcemia. Additional anamnesis reported only mild cramps in the calves during running this week. Family anamnesis was negative for calcium disorders. Chvostek’ and Trousseau’ sign were negative and a normal thyroid gland was felt. Further laboratory analysis revealed normal renal function, magnesium of 0.55 mmol/L, phosphate of 2.27 mmol/L, vitamin D of 71 nmol/L and an immeasurable PTH level of < 0.2 pmol/L. The diagnosis hypoparathyroidism was made and treatment was started with intravenous and oral calcium preparations, along with alphacalcidol and vitamin D3.

Further investigations into the origin of hypoparathyroidism were performed. An ultrasound of the neck showed no visible parathyroid glands. There were no signs of autoimmune polyglandular syndrome; autoimmune hypothyroidism, hypocortisolism and pernicious anemia were excluded. Infiltrative diseases (hemochromatosis, Wilson’s disease, and sarcoidosis) of the parathyroid glands were made unlikely by normal serum levels of ferritin, copper and ACE. Calcium-sensing receptor gene mutations were excluded. Primary idiopathic hypoparathyroidism was diagnosed. The patient was discharged from the hospital with oral calcium and alphacalcidol. During half a year, she maintained stable serum calcium levels. However, suddenly she developed hypercalcemia of 3.50 mmol/L. Serum PTH had increased to 0.4 pmol/L. In the literature, a few cases of remission in patients with idiopathic hypoparathyroidism are described. Time will tell whether or not our patient is in remission.

Conclusion: This case illustrates the importance of diagnosing hypoparathyroidism and frequent follow up during treatment. Both hypocalcemia at presentation and hypercalcemia caused by possible remission during treatment can be life-threatening.