Successful Use of Denosumab for Life-Threatening Hypercalcemia in a Pediatric Patient with Primary Hyperparathyroidism.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is rare and usually symptomatic in children. There is no approved medication to lower serum calcium levels in this patient group. Denosumab is used in adult patients with osteoporosis and hyperparathyroidism. To our knowledge, only 1 case of denosumab treatment in a child with severe PHPT has been reported to date. CASE PRESENTATION: A 16-year-old female was referred to our clinic with symptoms including pathologic fractures, nausea, emesis, and progressive weight loss. At admission, her serum total calcium was 4.17 mmol/L (reference range 2.15-2.55), parathyroid hormone 2,151 pg/mL (15-65), and phosphate 1.07 mmol/L (1.45-1.78). Due to potentially life-threatening hypercalcemia, denosumab 60 mg subcutaneously was administered after obtaining informed consent. Serum calcium levels were reduced within 12 h of injection and the patient's condition rapidly improved, which allowed genetic testing to be done prior to surgery. A heterozygous mutation in the CDC73 gene was revealed, and a parathyroidectomy was performed on day 22 after denosumab administration. Morphological examination revealed solitary parathyroid adenoma. After surgery, hypocalcemia developed requiring high doses of alfacalcidol and calcium supplements. CONCLUSION: Our case supports the previous observations in adults that denosumab can be safely and effectively used as a preoperative treatment in patients with PHPT and severe hypercalcemia and shows that it may be used in pediatric patients.

A registry for patients with chronic hypoparathyroidism in Russian adults.

Hypoparathyroidism and pseudohypoparathyroidism are rare endocrine disorders, characterized by low serum calcium due to inappropriate parathyroid hormone (PTH) levels or resistance to its action. There is little epidemiological information regarding chronic hypoparathyroidism in Russia. This study aims to build a registry database of Russian patients with chronic hypoparathyroidism who were referred for hospital treatment in order to conduct initial analysis of clinical presentations and hospital management. The Italian registry model was taken to be able to integrate our data in the future. Two hundred patients with hypoparathyroidism (n = 194) and pseudohypoparathyroidism (n = 6) were enrolled over 2 years (2017-2019). The most frequent cause of hypoparathyroidism was neck surgery (82.5%, mostly females), followed by idiopathic hypoparathyroidism (10%), syndromic forms of genetic hypoparathyroidism (4.5%) and forms of defective PTH action (3%). Calcium supplements and alfacalcidol were prescribed in most cases. However, a minority of patients (n = 6) needed to receive teriparatide as the only way to maintain calcium levels and to prevent symptoms of hypocalcemia. Consequently, substitution treatment with parathyroid hormone should be available in certain cases of hypoparathyroidism. This database will be useful to estimate the potential requirement for recombinant PTH in Russia and standards for clinical and therapeutic approaches.