Cholemic Nephrosis: An Autopsy Study of a Forgotten Entity

The aim of the study is to do a clinicopathologic study of post mortem kidney biopsies with significant deposition of bilirubin pigment within tubular epithelial cells and in the lumen of distal tubules as a bile cast.

All post mortem specimens with acute tubular necrosis, with the presence of bile casts in tubules or bile pigment deposition in the tubular epithelium during the period 2015-2018 were examined for gross and histopathology along with biochemical parameters and viral markers.

Bile casts with sloughed renal tubular epithelial cells and occasional macrophages were present in the distal convoluted tubule in 78.6% of biopsies (11/14). The plugging of distal convoluted tubule with casts was similar to that seen in myeloma and myoglobin cast nephropathies. Bilirubin pigment deposition was present in 35.7% (5/14) of cases. The frequency of bile casts in each biopsy was variable and it did not have any association with serum bilirubin levels or etiology of liver dysfunction. A striking difference from earlier studies is the high number of toxin-induced liver damage including six cases of paraquat and 2 cases of yellow phosphorus poisoning.

This study proves importance of the bile cast nephropathy as a reason for kidney injury, especially with varied hepatotoxic etiologies, especially paraquat and yellow phosphorus.