Jaundice

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"jaundice" AND "bilirubin"

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Jaundice

Jaundice (icterus) is the yellowish discoloration of the skin, sclera, and mucous membranes caused by accumulation of bilirubin. It becomes clinically visible when serum bilirubin rises above 2.5-3 mg/dL (normal <1 mg/dL). - Schwartz's Principles of Surgery, 11th Ed.

Bilirubin Metabolism - The Foundation

Bilirubin is produced primarily from breakdown of heme in red blood cells (and smaller amounts from myoglobin and cytochromes). Its metabolism has three phases:

Phase	What Happens
Prehepatic	Heme converted to insoluble unconjugated (indirect) bilirubin; transported bound to albumin
Intrahepatic	Unconjugated bilirubin taken up by hepatocytes and conjugated with glucuronic acid (via UGT1A1) to form water-soluble conjugated (direct) bilirubin
Posthepatic	Conjugated bilirubin excreted via bile ducts into duodenum; gut bacteria convert it to urobilinogen

Dysfunction at any phase causes jaundice. - Schwartz's Principles of Surgery

Classification by Phase (with Causes)

1. Prehepatic (Unconjugated Hyperbilirubinemia)

The conjugation system is overwhelmed by excess heme breakdown:

Hemolytic anemias (inherited: spherocytosis, G6PD deficiency, sickle cell; acquired)
- Direct Coombs positive = immune-mediated (autoimmune, drug-induced)
- Direct Coombs negative = non-immune (mechanical, microangiopathy, infections)
Ineffective erythropoiesis - thalassemia major, megaloblastic anemia (B12/folate deficiency), sideroblastic anemia, lead poisoning
Large hematoma resorption, massive tissue infarction
Albumin loss (burns, poor nutrition) - impairs unconjugated bilirubin transport to liver

Note: Hemolysis alone in a healthy liver cannot sustain bilirubin >4 mg/dL. Higher levels suggest concurrent hepatic dysfunction. - Harrison's Principles of Internal Medicine 22E

2. Intrahepatic (Hepatocellular or Cholestatic)

Unconjugated hyperbilirubinemia - conjugation defects:

Condition	Mechanism	Notes
Gilbert Syndrome	UGT1A1 activity reduced to 10-35% of normal; also impaired uptake	Common (up to 8% prevalence); bilirubin usually <3 mg/dL; exacerbated by fasting, stress, illness, alcohol; benign
Crigler-Najjar Type I	Complete absence of UGT1A1	Severe; kernicterus risk in neonates
Crigler-Najjar Type II	Markedly reduced UGT1A1 (>100 UGT1 mutations identified)	Less severe; residual enzyme activity
Physiologic neonatal jaundice	Immature UGT1A1 + enterohepatic recirculation	Self-limited; most neonates affected
Drug-induced	Rifampin, probenecid, novobiocin inhibit hepatic uptake	Resolves with drug cessation
Hypothyroidism	Impaired conjugation

Conjugated hyperbilirubinemia - excretion defects:

Condition	Mechanism
Dubin-Johnson syndrome	Impaired secretion of conjugated bilirubin from hepatocyte into canaliculi (MRP2 defect)
Rotor syndrome	OATP1B1/1B3 deficiency; interrupts conjugated bilirubin reuptake
Viral hepatitis	Hepatocellular injury disrupts secretion
Alcoholic hepatitis	Hepatocellular injury; can mimic obstruction
Drug-induced hepatitis	Many drugs - OTC agents, herbal supplements included
Primary biliary cholangitis (PBC)	Immune destruction of intrahepatic bile ducts
Primary sclerosing cholangitis (PSC)	Inflammatory stricturing of bile ducts
Ischemic hepatitis	Impaired hepatic blood flow
Sepsis	Endotoxin inhibits NTCP, MRP2, BSEP function
Cirrhosis	Combined liver insufficiency + portal hypertension
Intrahepatic cholestasis of pregnancy	Third trimester; BSEP/FIC1/MRP2/MDR3 gene polymorphisms; resolves postpartum
Acute fatty liver of pregnancy	Third trimester; microvesicular steatosis; can be fatal

Quick Compendium of Clinical Pathology, 5th Ed.; Sleisenger & Fordtran's GI & Liver Disease

3. Posthepatic (Obstructive/Extrahepatic - Conjugated)

Obstruction preventing bile flow into the duodenum:

Intrinsic obstruction:

Choledocholithiasis (most common cause of extrahepatic obstruction)
Benign biliary strictures (post-surgical: clips, ischemia, retained stones)
Cholangiocarcinoma
Cholangitis (bacterial infection - presents with Charcot's triad: fever, RUQ pain, jaundice)
Papilla of Vater disorders

Extrinsic compression:

Pancreatic carcinoma (classic painless progressive jaundice in elderly)
Pancreatitis / pancreatic pseudocysts
Lymph node compression
Schwartz's Principles of Surgery 11th Ed.

Key Lab Differentiation

Lab Finding	Suggests
ALP >3x ULN + transaminases <3x ULN	Cholestatic (obstructive)
Transaminases >3x ULN + ALP <3x ULN	Hepatocellular
Isolated unconjugated hyperbilirubinemia, all other LFTs normal	Gilbert's, hemolysis, Crigler-Najjar
Conjugated bilirubin >30% of total	Excretory defect (intrahepatic or posthepatic)
Leukocytosis + elevated amylase/lipase	Biliary obstruction / pancreatitis
Prothrombin time corrects with vitamin K	Cholestatic (fat-soluble vitamin malabsorption)
Prothrombin time does NOT correct	Hepatocellular synthetic failure
Thrombocytopenia	Cirrhosis (portal hypertension, reduced thrombopoietin)
Hemolytic anemia (positive Coombs, abnormal smear)	Prehepatic

Quick Compendium of Clinical Pathology 5th Ed.; Sleisenger & Fordtran's

Clinical Diagnostic Approach

Diagnostic algorithm for jaundice - Sleisenger & Fordtran's GI & Liver Disease

Four-step logical approach (Sleisenger & Fordtran's GI & Liver Disease):

History, physical exam, and baseline labs
Formulate working differential
Select specialized tests to narrow possibilities
Develop treatment/further testing strategy

History Clues

Suggests Obstruction	Suggests Liver Disease
RUQ pain, fever, rigors	Viral prodrome (anorexia, myalgias, malaise)
Prior biliary surgery	Known hepatotoxin exposure
Older age	Blood products / injection drug use
Palpable abdominal mass	Family history of liver disease

Physical Exam Clues

Cholangitis: fever, RUQ tenderness
Malignancy: painless jaundice, palpable gallbladder (Courvoisier's sign), weight loss
Cirrhosis: ascites, splenomegaly, spider telangiectasias, gynecomastia, caput medusae, asterixis
Wilson's disease: Kayser-Fleischer rings (pathognomonic)

History + physical + routine labs correctly classify jaundice as obstructive vs. non-obstructive in ~75% of cases. - Sleisenger & Fordtran's

Imaging Strategy

Abdominal ultrasound - first line if obstruction is suspected (checks for dilated bile ducts, stones, masses)
CT abdomen - better for extrahepatic masses, pancreatic pathology
MRCP - non-invasive biliary tree imaging; preferred when intermediate clinical suspicion
EUS - for distal biliary lesions, pancreatic assessment
ERCP - diagnostic AND therapeutic (stent placement, stone removal); used when obstruction confirmed

Special Contexts

Jaundice in Pregnancy

Hyperemesis gravidarum (1st trimester) - mild, self-limited
Intrahepatic cholestasis of pregnancy (3rd trimester) - pruritus + jaundice; resolves postpartum; gene polymorphisms in BSEP, FIC1, MRP2, MDR3
Acute fatty liver of pregnancy (3rd trimester) - microvesicular steatosis; can be fatal; requires urgent delivery
HELLP syndrome - hemolysis, elevated liver enzymes, low platelets; preeclampsia variant

Jaundice in Cirrhosis

Results from liver insufficiency (inability to excrete bilirubin). In cholestatic diseases (PBC, PSC) driving cirrhosis, biliary damage contributes additionally. Jaundice appearing in compensated cirrhosis signals the transition to decompensated cirrhosis (median survival drops from >12 years to ~1.6 years). - Goldman-Cecil Medicine

Jaundice in the Critically Ill

Broad differential: hepatic ischemia, blood transfusions, hepatotoxic drugs, parenteral nutrition, occult sepsis, renal injury. Even when clinical status improves, jaundice may lag in resolving - important not to over-investigate. - Sleisenger & Fordtran's

Neonatal Jaundice

Physiologic: UGT1A1 immaturity + enterohepatic recirculation of unconjugated bilirubin - peaks days 3-5, resolves by day 10-14
Pathologic: hemolytic disease, infection, Crigler-Najjar, metabolic disease
Phototherapy converts unconjugated bilirubin to water-soluble photoisomers for excretion without conjugation

Associated Symptoms

Pruritus - from bile salt accumulation; more prominent in cholestatic jaundice. Treated with cholestyramine, antihistamines, rifampin, opioid antagonists, gabapentin
Dark urine - conjugated bilirubin (water-soluble) spills into urine (bilirubinuria)
Pale/clay-colored stools - absent urobilinogen due to bile duct obstruction
Steatorrhea - fat malabsorption from absent bile in gut

Recent Evidence

Three recent reviews may be relevant:

Evaluation of Jaundice in Adults - Nelson M et al., Am Fam Physician 2025 (PMID 39823630) - practical clinical approach update
Managing neonatal hyperbilirubinemia: updated guideline - Chastain AP et al., JAAPA 2024 (PMID 39259272)
Neonatal Hyperbilirubinemia - Wickremasinghe AC et al., Pediatr Clin North Am 2025 (PMID 40619190)

Sources: Schwartz's Principles of Surgery 11th Ed. | Sleisenger & Fordtran's GI & Liver Disease | Harrison's Principles of Internal Medicine 22E | Goldman-Cecil Medicine | Quick Compendium of Clinical Pathology 5th Ed.

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