Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Laboratory | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Immunofluorescence description | Positive stains | Negative stains | Electron microscopy description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Wangsawibul S, Zuckerman J. Bile cast nephropathy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneybilecastnephropathy.html. Accessed June 1st, 2023.
Definition / general
- Acute or chronic renal tubular injury secondary to bile containing casts in the setting of hyperbilirubinemia
Essential features
- Presence of intratubular bile stained casts, especially in distal tubules / collecting ducts with acute tubular injury
- Associated with various hepatic diseases resulting in cholestasis and hyperbilirubinemia
Terminology
- Also called cholemic nephrosis, cholemic nephropathy, bile nephrosis, jaundice related renal insufficiency, jaundice associated acute kidney injury, bile acid nephropathy and bile nephropathy
- Bile cast nephropathy is a pathologic term that emphasizes the severe end of the spectrum of the renal injury in this unique clinical situation (Kidney Int 2013;84:192)
- Emphasizes the findings that can be directly observed on histologic examination of the renal tissue (bile casts)
- Bile salts can also cause tubular injury (tubulopathy) in the absence of bile cast (J Nephrol 2006;19:229)
- However, there is no characteristic biopsy finding in this setting
- In the absence of bile casts, the term cholemic nephropathy may be more appropriate
- May be difficult to distinguish from other causes of hepatorenal syndrome
ICD coding
- ICD-10: N28.9 - disorder of kidney and ureter, unspecified
Epidemiology
- Bile cast nephropathy is usually found in patients with advanced liver disease concomitant with cholestasis (Biochim Biophys Acta Mol Basis Dis 2018;1864:1356)
- Bile cast formation ranges from 2.6 - 73.5% of examined kidneys
- 61% of patients with cirrhotic jaundice and 100% of patients with alcohol induced cirrhosis (Kidney Int 2013;84:192)
Sites
- Renal tubules
Pathophysiology
- Direct tubular toxicity (J Nephrol 2006;19:229)
- Excess bilirubin believed to cause oxidative damage of the tubular cell membranes and uncoupling of mitochondrial phosphorylation (Hepatology 2013;58:2056)
- Sulfated bile salt inhibit Na-H, Na-K, Na-Cl pumps in proximal tubules and loop of Henle causing pH changes enhance bile cast deposition (Am J Physiol 1990;258:F986)
- Tubular obstruction
- Saturated bilirubin due to limited transportation in the proximal tubules leads to cast formation and tubular obstruction
- Bile acids are poorly water soluble which may also contribute to cast formation within the low pH microenvironment of the distal nephron
Etiology
- Any insult leading to profound bilirubinemia, usually > 20 mg/dL (Kidney Int 2013;84:192)
- Hepatic or extrahepatic causes including:
- Cirrhosis of any cause (e.g., alcohol, drug)
- Acute hepatitis
- Obstructive jaundice
- However, some etiologies of hyperbilirubinemia including cirrhosis due to hepatitis C virus infection and nonalcoholic steatohepatitis (NASH) show a lower propensity for bile casts (Kidney Int 2013;84:192)
- Hemolytic jaundice generally does not show bile casts formation (Kidney Int 2019;96:1400)
Clinical features
- Symptoms related to hepatic dysfunction including jaundice, pruritus, scleral icterus and abdominal distension (J Nephrol 2006;19:229)
- Acute or chronic renal dysfunction including oliguria, anuria and urine discoloration
Diagnosis
- Presence of bile stained tubular casts with acute tubular injury
Laboratory
- Increased serum creatinine, blood urea nitrogen, aspartate transaminase, alanine transaminase and bilirubin (elevated total bilirubin levels, typically > 20 mg/dL) (Kidney Int 2013;84:192)
- Presence of urinary muddy brown granular casts with bile staining and bile casts
Prognostic factors
- Reversibility of liver failure
- Reduction in serum bilirubin and bile acids might result in cessation of renal injury and renal recovery (World J Gastroenterol 2016;22:6328)
Case reports
- 41 year old woman with progressive abdominal distension, jaundice and renal failure (Hemodial Int 2015;19:132)
- 54 year old man with chronic kidney disease and chronic osteomyelitis with intractable pruritus, anorexia and jaundice (World J Gastroenterol 2016;22:6328)
- 56 year old man with painless icterus, severe pruritus, acute kidney injury and hyperbilirubinemia (Case Rep Nephrol Dial 2018;8:98)
- 61 year old man with obstructive cholestasis caused by common bile duct stones, elevated serum creatinine and proteinuria (Am J Kidney Dis 2017;69:143)
- 63 year old man with cholangiocarcinoma and chronic kidney disease (Clin Case Rep 2018;6:779)
Treatment
- Supportive treatment to reduce bilirubin burden and improve renal function including endoscopic retrograde cholangiopancreatography with stent replacement in case of biliary obstruction, plasmapheresis and hemodialysis
- Medical therapies including the use of steroids, cholestyramine, ursodeoxycholic acid and lactulose have shown minimal benefit (J Nephrol 2006;19:229)
- Liver or kidney transplantation
Gross description
- Yellowish discoloration of the renal cortex and medulla and green discoloration due to conversion of bilirubin to biliverdin after formalin fixation (renal medulla may show deeper green color due to higher concentration of bilirubin in distal nephron segments) (Kidney Int 2013;84:192)
Microscopic (histologic) description
- Pigmented greenish yellow or dark red granular cast material in tubular lumens (Kidney Int 2013;84:192)
- Pigmented casts more prominent in distal nephron segments
- Proximal tubules and Bowman space involvement in severe cases
- Casts associated with variable acute tubular injury
- Pigmented material in cytoplasmic tubular resorption droplets
- Mononuclear inflammatory cells in the vasa recta may be seen
- Bile does not polarize (Nephrol Dial Transplant 2010;25:1909)
Microscopic (histologic) images
Immunofluorescence description
- Bile cast should be negative by immunofluorescence
Positive stains
- Hall (Fouchet) stain reveals yellow or grayish green color intratubular casts
Negative stains
- Myoglobin and hemoglobin immunostain
- Iron (Prussian blue) stain
Electron microscopy description
- No specific findings
Sample pathology report
- Kidney, biopsy:
- Acute tubular injury with increased bile stained casts consistent with bile cast nephropathy
Differential diagnosis
- Other pigmented cast nephropathies:
- Myoglobin casts: positive for myoglobin
- Hemoglobin casts: positive for hemoglobin (Kidney Int 2019;96:1400)
- Acute tubular injury with granular cellular eosinophilic casts (cellular debris):
- Hall stain negative without brown bile stained casts
- 2,8-dihydroxyadeninuria (DHA) crystals:
- Polarizable brown crystals
- Bile does not polarize (Nephrol Dial Transplant 2010;25:1909)
- Light chain cast nephropathy:
- Presence of light chain monoclonality detected from immunofluorescence study
- Light chain casts also show a two tone red blue appearance on trichrome stain and are frequently associated with a cellular reaction
Board review style question #1
A patient with alcoholic cirrhosis has acute kidney injury. At autopsy their kidneys show numerous red-brown colored tubular casts most notably in distal tubules and collecting ducts. The casts stain positively on Hall stain. What do these renal histology findings represent?
- Myoglobin casts nephropathy
- Hemoglobin casts nephropathy
- Bile cast nephropathy
- Light chain cast nephropathy
- Oxalate nephropathy
Board review style answer #1
Board review style question #2
A pretransplant renal deceased donor allograft biopsy shows numerous red-brown colored tubular casts. The casts stain positively on Hall stain. Hemoglobin and myoglobin immunostains are negative. These histologic findings might indicate what disease in the donor?
- Fulminant hepatic failure in the setting of drug toxicity
- Rhabdomyolysis
- Hemolytic anemia
- Multiple myeloma
Board review style answer #2
A. Fulminant hepatic failure in the setting of drug toxicity
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Reference: Bile cast nephropathy
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Reference: Bile cast nephropathy