Differential Diagnosis for Urine with Protein and Bilirubin

Single Most Likely Diagnosis

• Chronic Kidney Disease (CKD) or Nephrotic Syndrome: The presence of protein in the urine (proteinuria) is a hallmark of kidney damage or disease. Bilirubin in the urine (bilirubinuria) can occur due to liver dysfunction or bile duct obstruction, but when seen alongside proteinuria, it suggests a systemic condition affecting both liver and kidney function, such as CKD or nephrotic syndrome, where liver congestion or dysfunction can lead to elevated bilirubin levels.

Other Likely Diagnoses

• Hepatorenal Syndrome: This condition involves rapid deterioration of kidney function in individuals with liver disease, often cirrhosis. The liver disease can lead to bilirubinuria, and the kidney dysfunction can cause proteinuria.
• Acute Kidney Injury (AKI): AKI can result from various causes, including medications, toxins, or ischemia. It can lead to proteinuria and, if associated with liver dysfunction, bilirubinuria.
• Liver Cirrhosis with Portal Hypertension: Cirrhosis can lead to liver dysfunction, causing bilirubinuria, and portal hypertension can lead to kidney dysfunction, resulting in proteinuria.

Do Not Miss Diagnoses

• Sepsis: Sepsis, especially when originating from a urinary tract infection or involving the liver (e.g., cholangitis), can cause both AKI (leading to proteinuria) and liver dysfunction (leading to bilirubinuria). Missing sepsis can be fatal.
• Malignancy (e.g., Lymphoma, Leukemia): Certain malignancies can affect both the liver and kidneys, leading to the presence of protein and bilirubin in the urine. These conditions require prompt diagnosis and treatment.

Rare Diagnoses

• Alagille Syndrome: A genetic disorder that affects the liver, heart, and other parts of the body. It can lead to liver dysfunction (causing bilirubinuria) and kidney abnormalities (causing proteinuria).
• Primary Biliary Cholangitis (PBC) with Renal Involvement: PBC is a chronic liver disease that can lead to liver dysfunction and, in some cases, associated kidney disease, resulting in both bilirubinuria and proteinuria.
• Amyloidosis: A condition characterized by the deposition of amyloid (a particular type of protein) in various organs, including the liver and kidneys. It can cause both liver dysfunction and kidney disease, leading to the presence of protein and bilirubin in the urine.