Background/objective: Little is known on the morphological changes in the kidneys of cirrhotic patients with abnormal urinalysis and/or high serum creatinine levels. This retrospective, one-point-in-time study aimed to report the results of the analysis of renal biopsy specimens obtained in patients with cirrhosis.
Methods: We retrieved information on 65 patients who underwent transvenous renal biopsy for proteinuria >0.5 g/day and/or microscopic haematuria and/or unexplained renal impairment (defined by serum creatinine levels >1.5 mg/dl).
Results: Fifty-one per cent of the patients had proteinuria >0.5 g/day, 58% had haematuria and 83% had renal impairment. Renal biopsy disclosed injury to glomeruli in 77% of the patients, to vessels in 69% and to the tubulointerstitium system in 94% (chronic in 77%; acute in 75%). Fibrous endarteritis was the most common renal vascular lesion. Injuries to different structures were frequently combined. Isolated glomerular alterations were found in only two patients. Acute tubular necrosis was significantly more common in patients with fibrous endarteritis than in those without. Among 18 patients with renal impairment, proteinuria <0.5 mg/day and no haematuria, 10 had glomerular lesions, 13 had chronic tubulointerstitial lesions and 12 acute tubulointerstitial lesions.
Conclusion: In patients with cirrhosis, various types of renal injuries are frequently combined. Chronic lesions (vascular or tubulointerstitial) may influence the outcome, in particular in patients who subsequently undergo liver transplantation and receive anticalcineurins. Renal vascular lesions may increase the risk of acute tubular necrosis. In patients with renal impairment, the absence of significant proteinuria and haematuria do not rule out the presence of renal lesions.