— 生理適應 · HARD · MCQ —
護理師評估一位疑似抗利尿激素不適當分泌症候群（SIADH）的病人，下列哪項實驗室數值符合診斷？
A nurse is evaluating a client with suspected SIADH. Which laboratory result is consistent with this diagnosis?
- ASerum sodium 125 mEq/L✓ 正解血清鈉 125 mEq/L
- BHematocrit 35%血比容 35%
- CSerum osmolality 300 mOsm/kg血清滲透壓 300 mOsm/kg
- DUrine specific gravity 1.002尿液比重 1.002
— Explanation · 中文詳解 —
SIADH 的生理機制是水分過度滯留，導致稀釋性低血鈉（小於 135 mEq/L）。低血鈉會導致腦細胞水腫，引發神經系統症狀。實驗室結果會顯示低血漿滲透壓與濃縮尿液。選項 A（Serum sodium 125 mEq/L）符合 SIADH 的低血鈉表現。其餘選項如高滲透壓或稀釋尿液，均與 SIADH 的病理機轉相反。
The pathophysiologic mechanism of SIADH is excessive water retention, leading to dilutional hyponatremia (less than 135 mEq/L). Hyponatremia causes cerebral cell edema and provokes neurologic symptoms. Laboratory results show low plasma osmolality and concentrated urine. Option A (serum sodium 125 mEq/L) is consistent with the hyponatremic presentation of SIADH. The other options, such as high osmolality or dilute urine, are contrary to the pathophysiology of SIADH.