Bile Cast Nephropathy

The term bile cast nephropathy (BCN), also known as cholemic nephropathy, icteric nephrosis, or cholemic nephrosis, is described as acute renal dysfunction, including acute kidney injury (AKI) in the setting of liver injury. Quincke first reported it in 1899 during autopsy examinations of patients with acute jaundice and renal insufficiency. BCN is a multidimensional entity resulting in tubular and interstitial inflammation, tubular obstruction, direct bile salt-induced tubular toxicity, and altered renal hemodynamics. This topic was actively discussed in the early 1900s but somehow not well investigated, contributing to its limited appearance in the current medical literature. The probable reasons it was overlooked may be because of a lack of consensus in the mechanism of the CN and diagnostic modalities in confirming the diagnosis.

The AKI in cholestatic liver dysfunction is usually linked with other unfavorable factors such as hypovolemia, endotoxemia, and exposure to nephrotoxins. On the other hand, the AKI in chronic liver injury patients is frequently attributed to hepatorenal syndrome (HRS), which is characterized by alternating intrarenal vasoconstriction and splanchnic vasodilation leading to functional and hemodynamic changes in the kidney. HRS could be described as type 1 and type 2. Type 1 HRS is a rapid renal failure with a serum creatinine level rising greater than 2.5 mg/dL in less than two weeks and is known for causing AKI. On the contrary, type 2 HRS is defined as a slower moderate decline in renal function with serum creatinine levels ranging between 1.5 and 2.5 mg/dL resulting in refractory ascites.

The definitive diagnosis of BCN is made by renal biopsy. However, the presence of impaired coagulation profile in most liver injury patients at the time of presentation makes kidney biopsy almost impracticable to perform, thus posing a diagnostic challenge. For all these reasons, BCN is frequently overlooked as a differential diagnosis of AKI in obstructive jaundice patients (The previous text taken from: Somagutta MR, et al. Bile Cast Nephropathy: A Comprehensive Review. Cureus. 2022;14(3):e23606. [PubMed link]).

Pinter K, Rosenkranz A. Cholemic Nephropathy: Role in Acute Kidney Injury in Cholestasis and Cirrhosis. Adv Kidney Dis Health. 2024;31(2):111-126. [PubMed link]
Annavarajula SK, Tandra VR, Ranga SK, Vennavalli S. Bile Cast Nephropathy, An Often-Missed Diagnosis. Indian J Nephrol. 2023;33(4):315-316. [PubMed link]
Ahmed K, Jaber F, Pappoppula L, Mohammed E, Aloysius MM. Bile Cast Nephropathy Due to Hepatitis A-induced Hyperbilirubinemia: A Case Report and Literature Review. Cureus. 2023;15(3):e35779. [PubMed link]
Zhao X, Huang R, Wong P, Fiset PO, Deschênes M. Renal tubular injury in hyperbilirubinemia: Bile cast nephropathy. Can Liver J. 2021;4(3):332-337. [PubMed link]
Somagutta MR, Jain MS, Pormento MKL, Pendyala SK, Bathula NR, Jarapala N, Mahadevaiah A, Sasidharan N, Gad MA, Mahmutaj G, Hange N. Bile Cast Nephropathy: A Comprehensive Review. Cureus. 2022;14(3):e23606. [PubMed link]