ADH分泌異常症候群を伴つた下垂体腫瘍の1例

A CASE OF PITUITARY ADENOMA ASSOCIATED WITH A SYNDROME OF INAPPROPRIATE SECRETION OF ANTIDIURETIC HORMONE

はじめに

　1950年，Petersら^7）が中枢神経系疾患において低Na血症を伴なつた症例を報告して以来，Cerebral salt wa—sting syndrome^7）2）やCerebral hyponatremia^3）4）の概念の下に数多くの報告がなされた。1957年Schwartzら^8）9）は肺癌患者の2例にみられた稀釈性の低Na血症を報告し，かつこの原因を抗利尿ホルモン（ADH）の分泌異常と推定した。以後同様の症状が他の悪性腫瘍，炎症，種々の中枢神経系疾患にもみられることがわかり，Syndrome of inappropriate secretion of antidiuretichormone （SIADH）という概念が提唱された^1）。

　われわれは最近，持続性の低Na血症を呈し，経過中にPitressinにより水中毒をきたしSIADHと診断され，血管写，気脳写，手術所見等より，視床下部への進展のみとめられた下垂体腫瘍の1例を経験したので，ここに報告する。

A syndrome of inappropriate secretion of ADHis quite rarely encountered in the literature and we recently experienced a case of the pituitary adenoma with sustained hyponatremia The patient was 61-year-old woman who was admitted and examined because of her severe polydipsia, polyuria, visual disturbance and headache.

The laboratory data showed continued hypona-tremia with renal overexcretion of sodium. The level of urine osmolality was always much greater than that of plasma. However, the renal and adrenal function showed no impairement.

On the clinical course, water intoxication appered by the injection of Pitressin Tannate. Pituitary tumor was surgically removed subtotally and the hypothalamic extention of tumor was confirmed.

This reported case might be classified in the syn-drome of inappropriate secetion of ADH as men-tioned by Schwartz et al.. The clinical diagnosis and the mechanism of hyponatremia were discussed.