Impact of peri-procedural subcutaneous parathyroid hormone on control of hypocalcemia in APS-1/APECED patients undergoing invasive procedures.

CONTEXT: The monogenic disorder autoimmune polyendocrine syndrome type 1 (APS-1) or autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) manifests frequently with hypoparathyroidism, which requires treatment with oral supplementation with calcium and active vitamin D analogs. The majority of APS-1/APECED patients also suffer from intestinal malabsorption, which complicates the management of hypoparathyroidism and may lead to refractory severe hypocalcemia. In such situations, reliance on intravenous calcium carries a high risk of nephrocalcinosis and renal damage.

METHODS: Here we report our experience of periprocedural subcutaneous administration of recombinant human parathyroid hormone (rhPTH 1-34) in APS-1/APECED patients. Serum calcium was measured up to five times within the 36-h period starting the evening before the scheduled procedure and ending the morning following the procedure.

RESULTS: Twenty-seven APS-1/APECED patients with hypoparathyroidism (ages 4-67 yo) underwent 31 invasive gastrointestinal and/or pulmonary procedures. The patients received an average rhPTH1-34 dose of 9.6 ± 1.4 mcg by subcutaneous injection. 92% of the adults and 54% of children in our cohort had evidence of nephrocalcinosis. Mean calcium levels remained stable and ranged from 2.06-2.17 mmol/L with minimal fluctuation. None of our patients experienced peri-procedural adverse events connected with hypocalcemia.

CONCLUSION: rhPTH 1-34 is an alternative to conventional therapy in patients with APS-1/APECED and hypoparathyroidism undergoing invasive procedures. Subcutaneous PTH1-34 given directly before and after procedures resulted in well-controlled serum calcium levels maintained in the low-normal range and avoided the need for intravenous calcium which may contribute to renal calcifications and tubular damage.