Bile Casts in the Kidney: A Clinicopathologic Study of 18 Autopsies
F Salem, SM Meehan, JB Taxy, A Chang. University of Chicago Medical Center, Chicago
Background: Acute kidney injury associated with liver dysfunction in jaundiced patients (historically termed cholemic nephrosis) is not well studied. Tubular injury by direct toxicity of bile salts and bilirubin has been proposed. To determine the pathologic spectrum of renal pathology that may be encountered in this clinical setting, we reviewed the autopsy findings of patients with severe liver dysfunction.
Design: The autopsy archives were reviewed between 2004 and 2008. 18 patients with a history of jaundice and liver failure were identified. Relevant clinical data, including liver and renal function tests and autopsy findings were reviewed with particular attention to the kidneys. A Hall's histochemical stain was performed on all cases to confirm the presence of intratubular bile. Immunohistochemistry (IHC) for Epithelial Membrane Antigen (EMA) which identifies distal nephron segments was used in a subset of cases to localize the presence of the intratubular bile casts. Iron stains and myoglobin IHC were used to exclude the possibility of other types of pigmented tubular casts in selected cases.
Results: Ages ranged from 5 weeks to 89 years. 10 patients had hepatorenal syndrome. Gross examination of the kidneys after formalin fixation showed green discoloration of the cortex in 6 cases. Bile pigment casts were focal and localized to the lumen of distal nephron segments in most instances. The extent of bile cast deposition correlated significantly with the serum conjugated bilirubin (R=0.8) and alkaline phosphatase (R= 0.7). (p<0.001 for each).
Conclusions: Bile casts were common in this series being present in the distal nephron segments of jaundiced patients at autopsy. The extent of intrarenal bile cast accumulation correlates with the severity of liver injury as measured by serum bilirubin and alkaline phosphatase. Intratubular bile casts may contribute to acute kidney injury by direct toxicity, nephron obstruction, or both.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 10, Wednesday Afternoon