[1708] Intrarenal Bile Casts in Hepatorenal Syndrome: A Common and Underrecognized Finding

Charles M van Slambrouck, Shane M Meehan, Anthony Chang. The University of Chicago Medical Center, Chicago, IL

Background: Acute renal failure is a common complication of severe liver injury, however the mechanisms are poorly understood. Bile nephrosis (also termed cholemic nephrosis) is characterized by the presence of intratubular bile casts and is rarely reported in jaundiced patients with liver dysfunction. We hypothesized that bile nephrosis could be a major cause of acute renal failure in this clinical setting. Therefore, we conducted this study to determine the prevalence and characteristics of intrarenal bile casts in patients with hepatorenal syndrome, which represents a severe subset of patients with liver failure.
Design: Archival paraffin embedded autopsies of all 13 patients with hepatorenal syndrome over a 7-year period were examined for the presence, extent, location, and characteristics of intratubular bile casts. Bile casts were confirmed with a Hall's stain. A Prussian blue iron stain was used to exclude the presence of hemoglobin casts. Histopathologic findings were correlated with relevant clinical and laboratory data.
Results: The mean age of the 13 hepatorenal syndrome patients was 53.5 years, with 7 males and 6 females. Intratubular bile casts were present in 7/13 of cases. Patients with few casts had mainly distal nephron involvement. In some severe cases (3/7), there was bile cast extension into more proximal nephron segments. Acute tubular injury (ATI) was present in 8/13, negative in 2/13, and indeterminate from autolysis in 3/13 cases. ATI was more frequent in patients with bile casts 5/13 versus those without 3/13. There was a trend toward higher total bilirubin (22.4 vs 14.2 mg/dL) and lower albumin (2.9 vs 3.7 g/dL) in patients with bile casts. Interestingly, patients with alcoholic cirrhosis may be more prone to tubular bile cast formation.

Cirrhosis Etiology and Bile Casts

Cirrhosis	Bile Casts	No Bile Casts
EtOH	4	0
EtOH / HepC	1	1
HepC	0	3
Other	2	2

Intratubular bile casts are acellular, have a pigmented yellow-green appearance on H&E and must be distinguished from bile tinged casts of sloughed epithelium, calcium oxalate, and Tamm-Horsfall protein.
Conclusions: Bile casts are present in a majority of hepatorenal syndrome patients at autopsy. In this clinical setting ATI is more frequent in patients with bile casts. This common finding is often not recognized and may represent an important contribution to renal dysfunction in this clinical setting through direct toxicity to the tubular epithelium, obstruction, or both. Additional studies need to be performed to determine whether the etiology of liver disease may predispose some patients to bile cast nephropathy.
Category: Kidney (does not include tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 292, Wednesday Afternoon