[A case of idiopathic hypoparathyroidism complicated with chronic thyroiditis].

It has been suggested that autoimmunity and genetic factors may play a specific role in the development of idiopathic hypoparathyroidism. We reported a case of idiopathic hypoparathyroidism complicated with chronic thyroiditis. The patient, a woman 40 years old, visited our clinic because of tetany of both hands and dizziness. She was of short stature with a round face. She also had a goiter, hypocalcemia, hyperphosphatemia and decreased parathyroidal function, but renal function was normal. Her TSH level was slightly high with a positive microsome test (x 1600), and the levels of thyroid hormones tended to be low. Based on Ellsworth-Howard test findings, a diagnosis of idiopathic hypoparathyroidism was made, with the complication of chronic thyroiditis confirmed by the thyroidal biopsy. Administration of l alpha-OH-D3 normalized the level of serum calcium. No special treatment was given for the chronic thyroiditis in order to observe its natural course. Her TSH returned to normal, and the level of thyroid hormones was increased to normal ranges. Tests were positive for anti-adrenal antibody and anti-gastric antibody. The complication of chronic thyroiditis, an autoimmune disease, and a positive finding for every antibody suggested the possible involvement of autoimmunity in the mechanism of development of idiopathic hypoparathyroidism. The administration of 1 alpha-OH-D3 resulted in an increase in the serum calcium level and also normalization of levels of TSH and thyroid hormones. Thus, it is likely that the elevation of the calcium ion or immunoregulation by active vitamin D may have induced the increase in thyroid hormone secretion.