一位患有抗利尿激素分泌不當症候群 (SIADH) 的病人入院。護理師應預期出現下列哪些實驗室檢查與臨床表現？（選所有適合的）
A client is admitted with Syndrome of Inappropriate Antidiuretic Hormone (SIADH). Which laboratory and clinical findings should the nurse expect? (Select all that apply.)
- ASerum sodium level of 128 mEq/L✓ 正解血清鈉濃度 128 mEq/L
- BUrine specific gravity of 1.035✓ 正解尿液比重 1.035
- CLow serum osmolality✓ 正解低血清滲透壓
- DIncreased urinary output尿量增加
- EPeripheral edema and weight gain without hypertension周邊水腫與體重增加，但無高血壓
SIADH 的核心病理生理是 ADH 分泌過多，導致腎小管對水的過度重吸收。這會造成「稀釋性低血鈉」與「細胞內水腫」。正確答案 A (低血鈉) 是因為體內水分過多稀釋了鈉離子；答案 C (低血清滲透壓) 與水分滯留一致。因為水分被重吸收到血液中，尿液會變得極度濃縮，故尿比重升高 (B)。選項 D 是錯誤的，SIADH 病人的尿量會「減少」而非增加。選項 E 是這題的陷阱：SIADH 雖然會有體重增加，但水分是分佈在細胞內外，通常不會出現顯著的外周水腫，也不一定會高血壓，因為這不是總體鈉超載，而是水的相對過多。臨床護理應嚴格限制液體攝入 (Fluid restriction)，並監測是否有神經系統症狀（低血鈉引起腦水腫）。
The core pathophysiology of SIADH is excessive ADH secretion, leading to over-reabsorption of water by the renal tubules. This produces dilutional hyponatremia and intracellular edema. Correct answer A (low serum sodium) reflects sodium dilution by water excess; answer C (low serum osmolality) is consistent with water retention. Because water is reabsorbed into the blood, the urine becomes highly concentrated, so urine specific gravity rises (B). Option D is incorrect because urine output is decreased, not increased, in SIADH. Option E is a trap: although clients with SIADH gain weight, fluid distributes both intra- and extracellularly and prominent peripheral edema typically does not appear, nor is hypertension necessarily present, because this is not a total sodium overload but a relative water excess. Clinical nursing care includes strict fluid restriction and monitoring for neurologic symptoms (cerebral edema from hyponatremia).
在美國，SIADH 的治療常使用 Vaptan 類藥物（Vasopressin receptor antagonists）且護理師需精確計算每小時入出量平衡；台灣臨床則多以嚴格限水 (500-800ml/day) 與補充高張 saline (3% NaCl) 為主，藥物使用選擇略有不同。