Saito Tomoyuki, Watanabe Yasutaka, Yuzawa Miho, Saito Takako, Tamemoto Hiroyuki, Suzuki Hisashi, Kusaka Gen, Omori Yoshio, Shinoda Soji, Kawakami Masanobu, Ishikawa San-e
Department of Medicine, Jichi Medical University Omiya Medical Center, Saitama, Japan.
Intern Med. 2007;46(10):653-6. doi: 10.2169/internalmedicine.46.6422. Epub 2007 May 24.
A 50-year-old man was admitted to determine the pathogenesis of hyponatremia. He had a poor appetite and was easily fatigued. Physical findings showed that he was conscious and alert. He had neither dry skin or tongue, nor pretibial edema. Laboratory data revealed that the serum sodium level was 110 mmol/l; plasma osmolality, 238 mmol/kg; and urinary osmolality, 417 mmol/kg. Plasma arginine vasopressin was 0.5 pg/ml despite plasma osmolality of 242 mmol/kg. An acute water load showed impaired water excretion, as percent excretion of water load was 30% and minimal urinary osmolality was 642 mmol/kg. Serum prolactin was 254 ng/ml, and anterior pituitary hormones of ACTH, TSH and GH were in the normal ranges. Brain magnetic resonance imaging (MRI) showed a pituitary tumor with a size of 20 x 22 x 21 mm and it pushed a pituitary stalk upward. Immunohistochemistry revealed prolactinoma. After the adenomectomy, serum sodium level has been kept normal with free access to water intake. The present study indicates that syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is manifested in association with pituitary macroadenoma of prolactinoma.
一名50岁男性因低钠血症的发病机制入院。他食欲不佳，容易疲劳。体格检查发现他意识清醒，警觉。他既没有皮肤或舌头干燥，也没有胫前水肿。实验室数据显示血清钠水平为110 mmol/l；血浆渗透压为238 mmol/kg；尿渗透压为417 mmol/kg。尽管血浆渗透压为242 mmol/kg，但血浆精氨酸加压素为0.5 pg/ml。急性水负荷试验显示水排泄受损，因为水负荷排泄百分比为30%，最低尿渗透压为642 mmol/kg。血清催乳素为254 ng/ml，促肾上腺皮质激素、促甲状腺激素和生长激素等垂体前叶激素在正常范围内。脑部磁共振成像（MRI）显示一个大小为20×22×21 mm的垂体瘤，它将垂体柄向上推移。免疫组织化学显示为催乳素瘤。腺瘤切除术后，血清钠水平在自由饮水的情况下一直保持正常。本研究表明，抗利尿激素不适当分泌综合征（SIADH）与催乳素瘤的垂体大腺瘤相关。
