APT: Liver

This week we will be discussing the Liver and Bile Collecting system. Please review NEJM review articles on cirrhosis and acute liver failure. In addition we are asking you to review ACG clinical guidelines for LFT interpretation/work up.

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Approach to Liver chemistries:

ALT: 33 (males), 25 (females), ALP: 115 (males), 100 (females)

Hepatocellular: ALT and AST both up

Cholestatic: ALP up and also direct hyperbilirubinemia

Infiltrative: ASLT up without significant bilirubin or AST or ALT elevation

Non-hepatic: Isolated AST elevated, indirect hyperbilirubinemia

Any degree of AST/ALT elevated:

• meds/toxins (aceteaminophen, certain abx, INH, MTX, NSAIDs, heparin, amiodarone, steroids, augment, sulfa drugs, allopurinol, etc)

• Alcohol related (alcoholic hepatitis usually >2:1 AST:ALT ratio)

• viral infections (Hep A-E, EBV, CMV, VZV, HSV)

• Sepsis /ischemia

• Biliary obstruction (mixed picture)

• NAFLD (usually AST and ALT elevated but <4x ULN)

If above: Workup includes, but not limited to:

• stop offending medications/toxins

• viral hepatitis serologies

• RUQ US (steatosis, cirrhosis, fibroscan)

• ANA, ASMA, LKM-1, IgG, Ceruloplasmin, urinary copper, Fe/TIBC >45%, ferritin >200,

Extreme elevation (AST/ALT >1000s, indicates some acute process)

• Ischemia (Shock, cardiac arrest, Budd-Chiari, usually AST/ALT goes up first then bilirubin increases)

• Meds/toxins (acetaminophen toxicity)

• Acute viral infection (Hep A-E, consider HBV reactivation)

• autoimmune hepatitis

• acute biliary obstruction

If above, workup includes, but not limited to

• INR, assess for hepatic encephalopathy, acute liver injury/failure

• stop offending meds/toxins, consider activated charcoal, N-acetylcysteine

• viral serologies

• RUQ US with dopplers

Cholestatic injury pattern (Increased ALP and biliriubin)

• Biliary obstruction (Choledocholithiasis, malignancy, primary sclerosis cholangitis, chronic pancreatitis w/ strictures)

• intrahepatic cholestasis: Medications (penicillin, cephalosporins, anabolic steroids, bactrim, TPN, sepsis, primary biliary cholangitis (PBC)

If above, workup with include, but not limited to

• RUQ US for obstruction

• MRCP or ERCP

• +/- liver biopsy

Infiltrative pattern (primarily ALP elevation)

• sarcoidosis or other granulomatosis (Tb)

• Malignancy (lymphoma, mets to liver, HCC)

• Amyloidosis

• abscess

If above, workup includes, but not limited to

• GGT, imaging with RUQ US or CT, MRCP

• Consider SPEP + IgG4

• +- liver biopsy

Acute Liver Failure

King’s College Criteria

• Acetaminophen induced liver failure: pH <7.3, or ALL 3 of INR > 6.5, Cr > 3.4, grades 3-4 Hepatic encephlopathy

• All other causes of ALF: INR >6.5 OR 3/5 of the following: age <10 or >40, Tbili >17, INR >3.5, time from jaundice to encephalopathy >7d, unfavorable etiology (Seronegative hepatitis, DILI, Wilson’s)
  

Decompensated Cirrhosis