Prevalence of Clinical Remission in Patients with Sporadic Idiopathic Hypoparathyroidism

Ravinder Goswami; Siya Goel; Neeraj Tomar; Nandita Gupta; Vanshika Lumb; Yagya Dutta Sharma

Disclosures

Clin Endocrinol. 2010;72(3):328-333. 

In This Article

Abstract and Introduction

Abstract

Background Remission of disease activity is a characteristic feature of autoimmune endocrine disorders such as Graves' disease, Addison's disease and occasionally in patients with premature ovarian failure. Autoimmunity is also implicated in sporadic idiopathic hypoparathyroidism (SIH) with clinical remission of disease reported in three cases.
Objective To assess the rate of remission in patients with sporadic idiopathic hypoparathyroidism and review the cases reported so far.
Subjects and methods Subjects included 53 patients (M:F, 24:29) with SIH who had been symptomatic for at least 1 year (range 1–31 years). They were treated with calcium and 1-α-(OH)D3/cholecalciferol therapy and had a mean duration of follow up of 5·0 ± 3·2 years. Treatment was withdrawn in two stages in the patients who maintained normal levels of serum total calcium during the preceding year of treatment. In stage-1, the dose of therapy was reduced to half and subsequently all treatment was stopped (stage 2) in those patients who maintained normal serum total calcium levels on the reduced dose. Remission of SIH was defined as maintenance of normal serum total (≥2·12 mmol/l) and ionized calcium, inorganic phosphorus and serum intact parathyroid hormone (iPTH) for at least 3 months after withdrawal of calcium and 1-α-(OH)D3/cholecalciferol therapy. Calcium sensing receptor autoantibodies (CaSRAb) were determined by Western blot.
Results Two of the 53 patients (3·8%) with SIH stayed in remission for 1 year after complete withdrawal of therapy. CaSRAb was absent in both the cases. The clinical features, age at onset and duration of hypocalcaemic symptoms in cases with remission were comparable to those who did no show remission.
Conclusion Sporadic idiopathic hypoparathyroidism is not irreversible as is widely believed and spontaneous remission of disease may occur in 3·8% of patients.

Introduction

Remission is a characteristic feature of autoimmune endocrine and nonendocrine disorders such as Graves' disease,[1,2] adrenal insufficiency,[3] premature ovarian failure,[4,5] vitiligo[6] and rheumatoid arthritis.[7] Blizzard et al. first identified autoantibodies to parathyroid tissue in sporadic idiopathic hypoparathyroidism (SIH) in 1966 and suggested that this disease may have an autoimmune origin.[8] Subsequently, four other studies have reported the presence of calcium sensing receptor autoantibodies (CaSRAb) in patients with SIH.[9–12]

Interestingly, there are three case reports of spontaneous remission in SIH.[11,13,14] We have a large cohort of patients with SIH on follow up.[9,15–18] One of them stopped her replacement therapy of calcium and cholecalciferol without medical consultation and returned for follow up after 3 years. She had no symptoms of hypocalcaemia and her serum total calcium, inorganic phosphorus and parathyroid hormone levels were normal. This observation prompted us to systematically assess for the possibility of remission in SIH.

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