Endocrine Abstracts

Introduction

Hypoparathyroidism still remains the only hormone-deficiency related disorder whose standard treatment is not based on replacing the missing hormone. In the last few years, there has been growing evidence on the use of recombinant human PTH, mostly with subcutaneous injections of rhPTH(1–34). More recently, some clinicians have tried to administer teriparatide through a continuous delivery system using insulin pumps.

Case report

A 31-year-old woman was referred to our Department for further evaluation of chronic severe hypocalcemia due to iatrogenic postsurgical hypoparathyroidism. She was chronically medicated with high doses of calcium, cholecalciferol, calcitriol, magnesium, indapamide and subcutaneous teriparatide injections. However, she still reported hypocalcemia symptoms on a daily basis and she frequently needed treatment with intravenous calcium perfusions due to episodes of severe hypocalcemia. During hospitalization, oral supplementation doses were progressively titrated up to 5g/day of elemental calcium and 4µg/day of alphacalcidol, with supervised treatment to rule out noncompliance. Despite these measures, six episodes of symptomatic severe hypocalcemia were documented, requiring treatment with intravenous calcium infusions. Our team then decided to implement a continuous subcutaneous perfusion of rhPTH(1–34) through an insulin pump. We slowly titrated the infusion rate up to 0.5 IU/h (30 mg/day). After that, no more severe hypocalcemia episodes occurred and we were able to reduce the oral supplementation doses. The treatment was monitored daily by clinical evaluation, dosing of serum ionized calcium and calculation of the urinary calcium:creatinine ratio. 4 months after hospital discharge, the patient remained with a rhPTH(1–34) infusion rate of 0.5 IU/h but it had been possible to fully suspend oral supplementation therapy. Her serum calcium level consistently remained within normal range and no other episodes of hypocalcemia occurred.

Discussion

The only way to effectively restore long-term calcium homeostasis in our patient was to start a continuous subcutaneous infusion of rhPTH(1–34). With this regimen, there was no need to maintain calcium or vitamin D supplementation. To our knowledge, this case represents the first report of successful treatment of hypoparathyroidism with a continuous perfusion of a PTH analogue in Portugal. We now have to closely monitor the incidence of potential adverse effects.