Endocrine Abstracts

JOINT3520

Introduction: Primary hypoparathyroidism is a rare cause of persistent hypocalcaemia and hyperphosphataemia in children. It may occur either as a component of a genetic syndrome e.g. 22q Deletion (DiGeorge Syndrome) or autoimmune processes in the parathyroid glands.

Case Presentation: We report a seventeen-year-old girl diagnosed with primary hypoparathyroidism at the age of ten, who initially presented severe hypocalcaemia with repeated seizures. The autoimmune hypoparathyroidism had been confirmed in the Department of Paediatrics, Endocrinology, Diabetology with Cardiology Divisions, Medical University of Białystok with low PTH concentration (<3pg/ml), typical biochemistry (total serum calcium concentration 0.8 mmol/l, plasma phosphate 4.1 mmol/l)and positive INF-omega antibodies. Other hormonal analyses showed no thyroid or adrenal disorders. Ultrasonography showed no parathyroid pathology. Long QTc (over 0.5 seconds) was present in the ECG. Hypocalcaemia was initially treated with intravenous and oral calcium, vitamin D₃ and vitamin D analogue - alfacalcidol. Sevelamer, a phosphate-binding drug was used for the management of hyperphosphataemia. Moreover the girl was given dietary recommendations to reduce phosphate in the diet. The patient was also treated with beta-blocker for LQTc syndrome. Although the calcium serum concentration increased initially, it remained below the normal reference range, and phosphate level remained over the norm despite the treatment. Other accompanying symptoms (intermittent fever, elevated CRP and radiological features of pneumonia and pericarditis) allowed the diagnosis of systemic lupus erythematosus (SLE) and the treatment with glucocorticoids was initiated, which improved parameters of calcium-phosphate balance. Further immunological examinations were negative for IL-22, IL-17A, IL-17F, IFN-lambda, IFN-alpha2A, and CaSR antibodies. Genetic diagnosis excluded AIRE and CaSR mutations. During first five years of therapy calcium concentrations persisted in the lower limit and phosphate concentration slightly above the norm with no clinical symptoms of electrolyte disorders. Attempts to increase oral calcium dosage resulted in a complication as nephrocalcinosis. After another two years of therapy the girl presented with hypocalcemia and hyperphosphatemia, that required the modification of the oral therapy. Her current daily calcium supplementation is 4 x 1000mg and phosphate-binding drug dosage is 4 x 800mg.

Conclusions: Although primary hypoparathyroidism is a rare endocrinopathy in children, it often causes therapeutic difficulties, as there is no standard hormone replacement therapy.