The Kidney in Cirrhosis

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Abstract
Certain aspects of renal function were investigated in 45 patients with cirrhosis and with variable degrees of impairment of hepatic function, without evidence of primary renal disease, hypotension, or gastrointestinal bleeding. Renal clearances of inulin and paraaminohippuric acid (PAH) were within normal ranges in patients without ascites and in the majority with responsive ascites, whereas these parameters were significantly reduced in all patients with relatively resistant ascites, especially when accompanied by azotemia. Thus, patients with resistant ascites and normal concentrations of blood urea demonstrated an impairment of renal hemodynamic function before the onset of azotemia. The majority had a proportionately greater reduction in PAH than in inulin clearance resulting in elevation of filtration fractions, thus strongly suggesting a diminution of blood flow to functioning nephrons. The ability to excrete a water load rapidly and to clear free water deteriorated with reduction of inulin and PAH clearances, but excessive renal tubular reabsorption of sodium occurred in all groups, irrespective of renal hemodynamic function and without significant relationship to the severity of ascites. In all groups, sodium, potassium, and their associated anions constituted an abnormally small fraction of the total osmolality of urine, whereas urea was the dominant osmotically active urinary substance. Impairment of renal function could not be correlated with hyperbilirubinemia, previous diuretic therapy, or mechanical factors due to the presence of ascites, and improvement of renal function appeared to be dependent on improvement of the liver disease. Infusions of metaraminol, mannitol, and aminophylline failed to produce significant alterations of inulin and PAH clearances, but metaraminol significantly increased the rates of urine flow. The abnormalities of renal function are discussed, both in relation to pathophysiologic considerations and in regard to clinical findings.