钾平衡与营养不良失钾性肾病

Potassium balance and malnutrition potassium-losing nephropathy

目的观察重度营养不良合并低钾血症患者钾平衡与失钾性肾病的关系。方法患者参与钾平衡研究,摄入膳食含钾等成分按照中央卫生研究院营养系编著的食物成份表计算;留24h尿;以洋红标记粪,取一份测氮,另取1/10标本置于500℃6h灰化,并以硝酸溶解后测电解质。采用钾平衡研究以确定当血清钾≤2.5mmol/L时,尿排出钾是否支持失钾性肾病的诊断标准。结果当血清钾正常后,停服氯化钾第5天血清钾降到1.5mmol/L,尿钾排出高达52mmol/24h,心电图再现缺钾表现。把氯化钾增加为40g/d仅服1d,患者显著好转,血清钾与心电图恢复正常。此后将氯化钾逐步减量直至停药。结论钾平衡显示血清钾降为1.5mmol/L而尿钾高达52mmol/24h,支持失钾性肾病的诊断。

Objective To determine the relationship between the potassium-losing nephropathy and severe malnutrition associated with severe kaliopenia. Methods The compositions of daily diet including potassium was obtained from the Nutrition Department of Central Hygiene Academy. 24 hours’ urine was collected. Carmine was used to mark feces, some was taken to detect nitrogen and 1/10 for the analysis of electrolytes after heat of 500℃ for 6hours and dissolution in nitric acid. Because the daily oral KCl must be progressively increased to 30g/d to approach normal serum K, the potassium balance was performed to present urine K excretion suggesting the diagnosis of potassium-losng nephropathy if the serum K was ≤2.5mmol/L. Results In the 5th day after stopping KCl, the serum K was 1.5mmol/L and the urinary excretion of K was 52mmol/24 h with kaliopenic electrocardiogram(ECG). Only one day after oral KCl 40 g was taken, the patient felt very healthy with normal ECG and serum potassium. Thereafter KCl is reduced and then stopped. Conclusions The potassium balance presenting that the serum potassium is 1.5mmol/L and the urinary excretion of potassium is 52mmol/24 h, suggests the diagnostic criteria of potassium-losing nephropathy.