Endocrine Abstracts

Background: Managing hypoparathyroidism in patients with autoimmune polyendocrine syndrome type 1 (APS-1) poses significant therapeutic challenges. The presence of gastrointestinal candidiasis and associated malabsorption complicates treatment and may lead to refractory hypocalcemia. The use of high doses of calcium and active vitamin D metabolites to regulate serum calcium levels frequently results in hypercalciuria, which may cause long-term complications. Consequently, replacement therapy with biologically active fragments of parathyroid hormone (PTH) such as teriparatide and rhPTH (1-84) has been suggested.

Case Report: Patient A. was diagnosed with APS-1 at the age of 10 when she presented with acute adrenal insufficiency and hypocalcemia. Notably, she suffered from cutaneous candidiasis since age 4. Genetic testing identified an R257X mutation in the AIRE gene. Achieving normocalcemia was exceptionally challenging, even with high doses of alfacalcidol (up to 20 μg/day). The patient frequently experienced hypocalcemic seizures, needing repeated calcium IV administrations. By age 24, she had already developed secondary complications such as cataracts and cerebral calcification (Fahr’s syndrome). At this point, patient A. began treatment with rhPTH 1-34 (teriparatide). Two daily injections of 20 μg (40 μg/d) were necessary to achieve normocalcemia. However, episodes of hypocalcemia still occurred occasionally. To lessen these calcium level fluctuations, she was transitioned to a continuous subcutaneous rhPTH 1-34 infusion via a pump. Three years following this adjustment, the patient opted to cease pump therapy in favor of conventional treatment with two to three daily injections of teriparatide (40-60 μg/day). At present, at the age of 35, the patient’s condition is well-managed with three daily injections of teriparatide (60 μg/day), alfacalcidol (4 μg/day), and calcium (3g/day). Additionally, she receives 20 mg of hydrocortisone for primary adrenal insufficiency and fluconazole for candidiasis. The patient experienced infrequent hypocalcemia episodes (once a year), likely due to low treatment adherence and reductions in teriparatide and vitamin D dosages contrary to medical advice.

Conclusion: Twelve-year continuous teriparatide treatment has successfully maintained normocalcemia without inducing hypercalciuria and significantly reduced alfacalcidol dose from 20 μg/d to 4 μg/d in the patient with severe hypoparathyroidism. No adverse effects of continuous long-term teriparatide therapy were noted.