Jaundice

Background

  • Bilirubin is end product of heme metabolism
    • All bilirubin products in the body are initially unconjugated
    • Transported from albumin into hepatocytes; combine with glucuronic acid into conj bili
      • Excreted into biliary tract in conjugated form
  • Only conjugated bilirubin is water-soluble (present in urine)
  • Nl bilirubin level is <1.1, 70% unconjugated

Jaundice Types

  • Prehepatic (overproduction)
    • Hemolysis
    • Primarily unconj bili
  • Hepatic (inadequate processing)
    • Viral, alcohol, toxin
    • Primarily unconj bili
  • Posthepatic (underexcretion)
    • Pancreatic tumor, choledocholithiasis
    • Primarily conj bili

Liver Function Tests

Transaminases

  • Transaminitis in hundreds a/w mild injury; thousands suggests extensive injury
  • Elevations <5x normal typical of alcoholic liver disease
  • AST:ALT ratio > 2 common in alcoholic hepatitis (alcohol stimulates AST production)
  • May be normal in end-stage liver failure
  • ALT more specific marker of hepatocyte injury than AST

Alk phos

  • Mild to moderate elevations accompany virtually all hepatobiliary disease
  • Elevations > 4x normal suggest cholestasis

GGT

  • Elevation in setting of hepatitis suggestive of alcoholic etiology

LDH

  • Moderate elevations are seen in all hepatocellular disorders and cirrhosis
  • Hemolysis results in elevation of LDH and unconj bili

Ammonia

  • Elevation doesn't correlate w/ acute worsening of hepatic function in cirrhotic pt
  • Serve as marker of generalized decline than as diagnostic tool or therapeutic end point

Coagulation Markers (PT/PTT/INR)

  • Marker of synthetic function
  • Correlation between PT prolongation and clinical outcome in fulminant liver disease

Albumin

  • Marker of synthetic function
    • Half-life is 3wk so less useful than PT in evaluating fulminant liver disease
  • Low levels also seen in malnutrition

Differential Diagnosis

Classification of Hyperbilirubinemia.jpeg

Indirect Hyperbilirubinemia

  • Hemolytic
    • G6PD
    • Drug related
    • Autoimmune
  • Hematoma resorption
  • Infective erythropoiesis
  • Gilbert's

Direct (Conjugated) Hyperbilirubinemia

Hepatocellular damage

Patient will have severely elevated AST/ALT with often normal Alkaline Phosphatase

Pregnancy Related

Transplant Related

  • Transplant rejection
  • Graft-vs-host

Pediatric Related

Additional Differential Diagnosis

Masqueraders

Only bilirubin stains the sclera

  • Carotenemia
  • Quinacrine ingestion
  • Dinitrophenol, teryl (explosive chemicals)

Diagnosis

Evaluation algorithm

Workup

  • Urine pregnancy
  • CBC
  • Chemistry
  • LFT
    • Hepatocyte injury: AST, ALT, alk phos
    • Hepatocyte catabolic activity: Bilirubin
  • Coags
    • Hepatocyte synthetic function
  • Albumin
    • Hepatocyte synthetic function
  • Ammonia
    • Hepatocyte catabolic activity
  • Acute hepatitis panel
  • Lipase
  • UA
  • ?US vs. CT
  • ?Retic count
  • ?Haptoglobin/LDH
  • ?APAP/ASA/Utox/ETOH

Disposition

New Onset Jaundice Admission Criteria

  • Transaminase >1000IU/L
  • Tbil >10mg/dL
  • Evidence coagulopathy

See Also

References