化学療法後に低ナトリウム血症を生じた上咽頭癌症例

A Case of Hyponatremia, Polyuria and Hypopituitarism with Nasopharyngeal Carcinoma

　はじめに

　抗癌剤の使用によりsyndrome of inappropriate-secretion of antidiuretic hormone （SIADH）および低ナトリウム血症が誘発されることが報告されている^1〜4）。今回，われわれは頭蓋内浸潤による下垂体機能低下を合併した上咽頭癌症例にシスプラチンを含む多剤併用化学療法を施行し，これを契機に多尿と低ナトリウム血症をきたした症例を経験したので，文献的考察を加えて報告する。

A patient with nasopharyngeal carcinoma dest-ructing the skull base, developed hyponatremia and polyuria, folloing 5-Fu and CDDP chemotherapy. At first, hypopituitarism was not detected, and a drug-induced syndrome of inappropriate secre-tion of antidiuretic hormone was suspected. MRI showed pituitary gland pushed upward by intra-cranial tumor. Glucocorticoid deficiency by hypopituitarism due to nasopharyngeal carcinoma and extracellular volume excess by chemotherapy caused hyponatremia and polyuria. As the intra-cranial tumor was diminished by chemotherapy and irradiation, function of pituitary gland, hyponatremia and polyuria were improved. The necessity of the evaluation of pituitary gland function before chemotherapy in T₄ nasopharyn-geal carcinoma was recommended.