洞機能不全を呈したADH分泌異常合併の下垂体腺腫—1治験例

The syndrome of inappropriate secretion of antidiuretic hormone caused by pituitary adenoma presenting sick sinus syndrome:A case report

　低Na血症は比較的よく遭遇する電解質代謝異常であるが，臨床的に問題となる調律異常が発現する例はまれである。

　今回著者らは，下垂体腺腫に抗利尿ホルモン（ADH）分泌異常症（SIADH）を合併し，その低Na血症によりAdams-Stokes発作を伴う洞機能不全症候群（SSS）を呈したと考えられるきわめてまれな1例を経験した。

A 71-year-old male was hospitalized for evaluation of syncope and general fatigue. His heart rate was 36/ min, and it was thought to be Adams-Stokes syndrome due to sinus node dysfunction. He was also found to have marked hyponatremia (106 mEq/l) and plasma hypoosmolatity (221 mOsm/kg), and subsequent pitui-tary adenoma. Since the patient exhibited no adrenal insufficiency, he was diagnosed as a syndrome of in-appropriate secretion of antidiuretic hormone (SIADH) due to chromophobe adenoma with suprasellar extension. After subtotal resection of the tumor was successfully carried out, his hyponatremia was corrected, and normal sinus rhythm was gained.

This is considered to be a very rare case of sinus node dysfunction caused by marked hyponatremia in SIADH secondary to pituitary adenoma.