Bile Casts Found in Kidney Injury with Severe Liver Dysfunction

Renal bile casts are common in patients with severe hepatic dysfunction, and they may play an important role in the development of kidney injury, reports a study in Kidney International.

The clinicopathologic study included 44 patients with confirmed jaundice, identified at one university pathology department between 2004 and 2011. The presence and associations of intrarenal bile cast formation were analyzed by use of autopsy specimens in 41 cases and renal biopsy specimens in three.

Bile casts involving distal nephron segments were found in 24 of the 44 jaundiced patients. Bile cast nephropathy was considered mild in 16 cases but severe in eight, with extension to the proximal tubules. Tubular bile casts were found in 11 of 13 patients with hepatorenal syndrome and in all 10 with alcoholic cirrhosis. Jaundiced patients with bile casts had significantly increased total and direct bilirubin levels, with a trend toward increased creatinine and liver enzyme levels.

Published studies from the 1950s and 1960s reported on intrarenal bile casts as a mechanism of kidney dysfunction in patients with liver failure—previously termed “cholemic nephrosis” or “bile nephrosis.” However, in recent years little attention has been given to the concept of cholemic nephrosis or the pathologic relevance of renal bile casts.

The new study shows a high rate of intrarenal bile casts among patients with clinical jaundice. Bile casts may contribute to kidney injury via direct bile and bilirubin toxicity as well as by tubular obstruction.

The authors propose the term “bile cast nephropathy” as a condition causing impaired renal function in patients with severe liver dysfunction. It can affect adults and children with a wide range of hepatic disorders, with or without cirrhosis. The researchers call for further studies to clarify the prognostic and clinical implications of bile cast nephropathy [van Slambrouck CM, et al. Bile cast nephropathy is a common pathologic finding for kidney injury associated with severe liver dysfunction. Kidney Int 2013; 84:192–197].