Magner P O, Ethier J H, Kamel K S, Halperin M L
Renal Division, University of Calgary, Alberta.
Clin Invest Med. 1991 Aug;14(4):355-8.
One purpose of this report is to illustrate that calculating the rate of excretion of osmoles in the urine can be of value in the differential diagnosis of hypernatremia and polyuria. A second purpose is to illustrate a clinical example where the osmolality of the urine did not reflect the lack of action of ADH. A patient with ethanol intoxication seemed to have central diabetes insipidus on clinical grounds. However, the osmolality of the urine was 287 mosm/kg H2O, a value which made this diagnosis unlikely. Since the concentration of ethanol in plasma was 119 mmol/L, we suspected that the urine contained an appreciable quantity of alcohol; this might obscure the lack of action of ADH. A study was performed to document the quantitative relationship between the concentrations of ethanol in plasma and urine. The concentration of ethanol in the urine was approximately 1.4-fold greater than in plasma. Using this correction factor, the osmolality of the urine adjusted for ethanol in the patient was only 120 mosm/kg H2O, a value more consistent with the diagnosis of central diabetes insipidus.
本报告的一个目的是说明，计算尿中渗透摩尔排泄率在高钠血症和多尿的鉴别诊断中可能具有价值。第二个目的是举例说明一个临床实例，即尿渗透压并未反映抗利尿激素（ADH）作用缺乏的情况。一名乙醇中毒患者基于临床症状似乎患有中枢性尿崩症。然而，其尿渗透压为287 mosm/kg H₂O，这一数值使得该诊断不太可能。由于血浆中乙醇浓度为119 mmol/L，我们怀疑尿中含有相当数量的酒精；这可能掩盖了抗利尿激素作用的缺乏。进行了一项研究以记录血浆和尿中乙醇浓度之间的定量关系。尿中乙醇浓度约比血浆中高1.4倍。使用这个校正因子，该患者经乙醇校正后的尿渗透压仅为120 mosm/kg H₂O，这个数值更符合中枢性尿崩症的诊断。
