Fractional excretion of beta-2-microglobulin in the urine of patients with normal or reduced renal function and hepatic coma

The purpose of this prospective study was to evaluate beta-2-microglobulin (beta 2m) as a differential diagnostic indicator between hepatic nephropathy (HN) and acute tubulointerstitial nephropathy (ATIN) in patients with reduced renal function and hepatic coma, and to determine whether beta 2m excretion could be used as a marker of renal impairment before increased serum creatinine (S-Cr) concentration or decreased creatinine clearance (Cr-Cl). Finally, the use of beta 2m as a prognostic indicator was investigated. Eighteen patients in hepatic coma grade III-IV were entered in the study and were divided into two groups in accordance with their renal function (serum creatinine above/below 180 mumol/l). The fractional excretion of beta 2m (FE-beta 2m) was used to monitor beta 2m elimination. The study failed to show any distinction in FE-beta 2m between HN and ATIN patients, presumably owing to the small number of patients. FE-beta 2m could not predict the development of renal failure earlier than the increase in S-Cr or decrease in Cr-Cl. However, a few patients who survived paracetamol intoxication had increased FE-beta 2M in the beginning of the coma and normal S-Cr and Cr-Cl. Patients who died as a result of paracetamol intoxication had both abnormal FE-beta 2m and abnormal S-Cr and Cr-Cl, suggesting that if therapy had been initiated earlier, when only FE-beta 2m was affected, these patients might have survived. All patients who survived, except three paracetamol- and one aminoglycoside-intoxicated patient, had normal FE-beta 2m in the beginning of the coma.(ABSTRACT TRUNCATED AT 250 WORDS)