​Symptoms and Signs – Differential Diagnosis of  Jaundice in the Adult Patient
PREHEPATIC CAUSES
• Unconjugated hyperbilirubinemia: excessive heme metabolism from hemolysis (e.g., sickle cell disease, spherocytosis, G6PD, immune hemolysis), ineffective erythropoiesis (e.g., thalassemia, folate, severe iron deficiency), or large hematoma reabsorption

INTRAHEPATIC CAUSES
• Unconjugated hyperbilirubinemia: disorders of enzyme metabolism such as Gilbert’s disease (common, benign), Crigler- Najjar syndrome (rare, severe), or drugs such as rifampin and probenecid
• Conjugated hyperbilirubinemia: intrahepatic cholestasis
• Viruses: hepatitis A, B, and C; Epstein-Barr
• Alcohol: alcoholic hepatitis, alcoholic cirrhosis
• Autoimmune: primary biliary cirrhosis, primary sclerosing cholangitis
• Drug induced: acetaminophen, penicillins, oral contraceptives, chlorpromazine (Thorazine), steroids (estrogenic or anabolic), some herbals
• Hereditary metabolic: hemochromatosis, Wilson’s disease, Dubin- Johnson and Rotor’s syndromes, α1-antitrypsin deficiency
• Systemic disease: sarcoidosis, amyloidosis, glycogen storage diseases, celiac disease, tuberculosis, Mycobacterium aviumintracellulare
• Other: sepsis, total parenteral nutrition, pregnancy, graft-versushost disease, environmental toxins

POSTHEPATIC CAUSES
• Conjugated hyperbilirubinemia: intrinsic or extrinsic obstruction of the biliary system
• Intrinsic blockage: gallstones, cholangitis, strictures, infection (e.g., cytomegalovirus, Cryptosporidium in AIDS patients, parasites cholangiocarcinoma, gallbladder cancer)
• Extrinsic blockage: pancreatitis, pancreatic carcinoma, pancreatic pseudocyst
• Pseudojaundice: caused by an excessive ingestion of foods containing beta-carotene (carrots, melons, squash); does not result in hyperbilirubinemia or scleral icterus