Korean Journal of Nephrology 1996;15(3):278-288.

대사성 산증의 감별진단 지표들의 임상적 유용성

전은실 , 오지은 , 허우성 , 조윤숙 , 김연수 , 안규리 , 한진석 , 김성권 , 이정상 , 정용영 , 김근호

Abstract

The plasma anion gap have several pitfalls in differential diagnosis of metabolic acidosis, New classification of metabolic acidosis based on the pa- thophysiologic mechanism was proposed. And urine Ph, urine anion gap and urine osmolal gap were suggested as the indirect indices of urinary ammo- nium excretion. But, clinical usefulness of these indices for differential diagnosis of metabolic aci- dosis have not been clarified. We purposed to verify clinical usefulness of various indices of metabolic acidosis in differential diagnosis of metabolic acidosis based on the pathophysiologic classification. Four diabetic ketoacidosis and seven lactic acidosis patients were included as acid overproduction group, four distal renal tubular acidosis and seventeen chronic renal failure patients were included as acid underexcretion group, and eight normal adults with acid (ammonium chloride) loaded included as control group. 1) Plasma bicarbonate was not different between acid overproduction group (13.2±1.6mmol/L) (mean standard error) and acid underexcretion group (14.6 0.7mmol/L). Phsma bicarbonate in control group was 19.6±0.6mmol/L. 2) Plasma anion gap in acid overproduction group (25.9±2.2mmol/L) was higher than in acid under excretion group (11.9±1.2mmol/L) and control group (13.5± 0.6mmol/L) (p<0.05). 3) DAG /AHCC was higher in acid overpro- duction group (1.5±0.3) than in acid underexcretion group (-0.1±0.1) and control group (0.30.2) (p<0.05). There was no difference within acid over- production group (diabetic ketoacidosis: 1.20.1 and lactic acidosis - 1.7±0.4). 4) Urinary ammonium excretion in acid under- excretion group (13.81.9mmoVday) was higher than in acid overproduction group (82.216.7mmoV day) and control group (52.6±3.7mmol/day)(p<0.05). 5) Urine anion gap was not different between acid overproduction group (39.8±15.3mmol/L) and acid underexcretion group (37.4±3.3mmol/L) But, control group had lower urine anion gap(-16.2 ±5.5mmol/L) than the other two groups. 6) The fractional excretion of unmeasured anion in acid underexcretion group (37.9±4.0%) was higher than in acid overproduction group (4.6±2.0%) and control group (-1.0±0.4%)(p<0.05). The cut-off value of fractional excretion of unmeaseured anion to differentiate the acid overproduction group from the acid underexcretion group was 10%. In conclusion, plasma anion gap, AG /AHCC and fractonal excretion of unmeasured anion were useful to differentiate metabolic acidosis based on the pathophysiologic classification,