THE SPECTRUM OF HYPOCALCAEMIA IN AUTOIMMUNE POLYENDOCRINOPATHY, CANDIDIASIS, ECTODERMAL DYSPLASIA AND THE PHENOMENON OF TREATMENT RESISTANCE

O. Neylon, D. Cody, M. McKenna, C. Costigan. OLCHC, Crumlin, Dublin, Ireland

Background: Patients with autoimmune polyendocrinopathy, candidiasis, ectodermal dysplasia (APECED) (AIRE mutation positive) are particularly susceptible to hypocalcaemia. This is due to a complex interplay between hypoparathyroidism, autoimmune enteropathy and as yet unknown factors.

Aim: We describe the spectrum of hypocalcaemia encountered in patients with APECED and the range of therapies used in its treatment, from low-dose alfacalcidol (1-alpha) to major immunosuppressive therapy.

Methods: Data were collated from the Irish APECED population (n  =  31).

Patients: 26 patients had hypoparathyroidism, all treated with 1-alpha. Hypocalcaemia secondary to hypoparathyroidism initially presented at a mean of 7 years.

Results: Many patients required supraphysiological dosages of 1-alpha. In addition, four patients required daily subcutaneous parathyroid hormone (PTH) injections, of which three progressed to intravenous calcium dependency (after up to 4 years of PTH). They had four episodes of prolonged intravenous dependency with requirements for very high calcium dosages (up to 0.99 mmol/kg per day). All patients had comorbid autoimmune enteropathy. All patients had normal serum albumin. The urinary calcium : creatine ratio was appropriately suppressed in all patients; however, all had preceding nephrocalcinosis. At present, one patient is maintained on a daily bolus of intravenous calcium, in addition to 1-alpha 25 μg twice a day. One patient was weaned from intravenous calcium after 6 days with intramuscular vitamin D stosstherapy and megadose 1-alpha (20 μg twice a day). One patient remained on continuous intravenous calcium infusion for a total of 48 days and was weaned after therapy with high-dose prednisolone, mycophenolate mofetil and intravenous 1-alpha. Previous unsuccessful treatments included pulsed methylprednisolone, vitamin D stosstherapy and azathioprine.

Conclusion: The range of hypocalcaemia in patients with APECED is wide …