From the Guidelines
The evaluation and management of a patient with elevated urine bilirubin should begin with a comprehensive history, physical examination, and laboratory tests, including serum bilirubin, liver enzymes, complete blood count, and coagulation studies, as conjugated hyperbilirubinemia suggests liver or biliary tract disease. The presence of bilirubin in urine indicates conjugated hyperbilirubinemia, which can be due to liver or biliary tract disease 1. Initial assessment should include:
- Comprehensive history and physical examination
- Laboratory tests:
- Serum bilirubin (conjugated and unconjugated)
- Liver enzymes (ALT, AST, ALP, GGT)
- Complete blood count
- Coagulation studies Imaging studies such as abdominal ultrasound should be performed to evaluate the liver and biliary system for obstruction, masses, or structural abnormalities 1. Management depends on the underlying cause:
- Biliary obstruction: endoscopic retrograde cholangiopancreatography (ERCP) may be needed for stone removal or stent placement
- Hepatitis: specific treatments vary by etiology (antivirals for viral hepatitis, corticosteroids for autoimmune hepatitis)
- Drug-induced liver injury: the offending agent should be discontinued Supportive care includes adequate hydration, nutritional support, and monitoring for complications of liver dysfunction. Ursodeoxycholic acid (10-15 mg/kg/day) may be prescribed for certain cholestatic conditions 1. The most recent guidelines recommend a tiered approach towards investigating liver test abnormalities, evaluating the most likely alternative causes of liver injury first, before moving onto investigations for rarer causes of liver injury 1.
From the Research
Evaluation Approach
The evaluation and management approach for a patient with elevated urine bilirubin levels involves several steps:
- A comprehensive medical history, review of systems, and physical examination to differentiate potential causes such as alcoholic liver disease, biliary strictures, choledocholithiasis, drug-induced liver injury, hemolysis, or hepatitis 2
- Initial laboratory evaluation should include assays for bilirubin (total and fractionated), a complete blood cell count, aspartate transaminase, alanine transaminase, gamma-glutamyltransferase, alkaline phosphatase, albumin, prothrombin time, and international normalized ratio 2
- Measuring fractionated bilirubin allows for determination of whether the hyperbilirubinemia is conjugated or unconjugated 2, 3
Diagnostic Considerations
The following diagnostic considerations should be taken into account:
- Unconjugated hyperbilirubinemia occurs with increased bilirubin production caused by red blood cell destruction, such as hemolytic disorders, and disorders of impaired bilirubin conjugation, such as Gilbert syndrome 3
- Conjugated hyperbilirubinemia occurs in disorders of hepatocellular damage, such as viral and alcoholic hepatitis, and cholestatic disorders, such as choledocholithiasis and neoplastic obstruction of the biliary tree 3
- Liver function tests, including biochemical parameters, bilirubin and albumin levels, and coagulation tests, are commonly used in the routine screening of patients with liver disease 4
Imaging and Further Evaluation
Imaging and further evaluation may include:
- Ultrasonography of the abdomen, computed tomography with intravenous contrast media, and magnetic resonance cholangiopancreatography to differentiate between extrahepatic obstructive and intrahepatic parenchymal disorders 2, 3
- Liver biopsy may be required to establish the diagnosis, prognosis, and management of the disease if the etiology of jaundice is unclear despite laboratory testing and imaging 2