354.4 📋 章末速蚘 Summary

354.4.1 🔑 䞀句話瞜結

Liver functionsmetabolic + synthetic + detoxification + storage + immunologicalLFTs (liver function tests) patterns(1) hepatocellular — AST + ALT ↑ ; (2) cholestatic — ALP + GGT ↑ ± bilirubin; (3) synthetic dysfunction — albumin (chronic, tÂœ ~ 21 d), PT/INR (acute, vitamin K-dependent factors)AST:ALT ratio: > 2 with GGT high = alcoholic liver disease; > 1 = cirrhosis (any cause) or muscle/ischemic; < 1 = most chronic liver disease (NAFLD, viral, autoimmune)bilirubin metabolism: heme → biliverdin → unconjugated bilirubin → albumin transport → hepatic OATP uptake → UGT1A1 conjugation → conjugated bilirubin → MRP2 canalicular excretion → bile → intestinal bacteria → urobilinogen → enterohepatic reabsorption + urobilin (urine) + stercobilin (feces)hereditary hyperbilirubinemiaGilbert syndrome (UGT1A1 mutation, ~ 5-10% prevalence, benign, mild unconjugated, ↑ with fasting/stress, no treatment) + Crigler-Najjar Type I (severe UGT1A1 — kernicterus risk, phototherapy + liver transplant) + Type II (partial — phenobarbital responsive) + Dubin-Johnson (MRP2 — conjugated + dark liver) + Rotor (OATP — conjugated, liver not pigmented)jaundice categories(1) pre-hepatic — hemolysis + Gilbert + Crigler-Najjar (unconjugated bilirubin)(2) hepatic — viral hepatitis + ALD/NAFLD + AIH + DILI + Wilson + hemochromatosis + cirrhosis + ischemic (mixed bilirubin)(3) post-hepatic / cholestatic — extrahepatic obstruction (choledocholithiasis, pancreatic cancer, cholangiocarcinoma, strictures) + intrahepatic cholestasis (PBC, PSC, drug-induced, cholestasis of pregnancy, TPN, sepsis) (conjugated bilirubin)approach to abnormal LFT framework(1) pattern recognition; (2) clinical context + history; (3) ultrasound abdomen first (steatosis, biliary dilation, masses); (4) serology (viral hepatitis, autoimmune, metabolic — iron/copper, alpha-1 antitrypsin); (5) liver biopsy if uncertain; (6) non-invasive fibrosis assessment (FIB-4, NFS, ELF, FibroScan, MR elastography)acute hepatitis (ALT > 1000) differential = drug (acetaminophen), viral (HAV/HBV/HCV/HEV), autoimmune (less commonly), ischemic, Wilson fulminant, HSV。

354.4.2 💊 治療粟芁

  • diagnostic workupLFT pattern recognition + clinical history + ultrasound first + serology (HBV, HCV, autoimmune, metabolic) + biopsy if uncertain
  • fibrosis assessmentFIB-4 score (age + AST + ALT + platelets) — population screening → FibroScan / MR elastography → biopsy if discordant
  • Gilbert syndromeno treatment + reassurance
  • Crigler-Najjar Type Iphototherapy + liver transplant (definitive)
  • Crigler-Najjar Type IIphenobarbital responsive (UGT1A1 induction)
  • Dubin-Johnson + Rotorno specific treatment + benign
  • cholestasis of pregnancyursodeoxycholic acid (UDCA) + close monitoring + delivery near term
  • DILI (drug-induced)stop offending drug + supportive + N-acetylcysteine for acetaminophen + RUCAM causality assessment
  • specific etiology treatments per Ch354-360

354.4.3 🎯 盧醫垫的考前提醒

  1. LFT pattern recognition criticalhepatocellular (AST + ALT ↑↑) vs cholestatic (ALP + GGT ↑↑) vs mixed vs isolated hyperbilirubinemia
  2. AST:ALT ratio interpretation> 2 with GGT high = alcoholic liver disease (mitochondrial AST); > 1 = cirrhosis/muscle/ischemic; < 1 = most chronic liver
  3. bilirubin metabolism pathwayheme → unconjugated bilirubin → UGT1A1 (conjugation) → conjugated bilirubin → MRP2 (canalicular excretion) → bile
  4. Gilbert syndrome~ 5-10% prevalence + UGT1A1 promoter polymorphism + mild unconjugated hyperbilirubinemia + ↑ with fasting/stress/illness + benign, no treatment
  5. Crigler-Najjar Type I vs IIType I severe UGT1A1 deficiency (kernicterus, transplant needed); Type II partial (phenobarbital responsive — induces residual UGT1A1)
  6. Dubin-Johnson vs Rotorboth conjugated hyperbilirubinemia + benign; Dubin-Johnson MRP2 defect + dark liver on biopsy; Rotor OATP1B1/1B3 defect + normal liver
  7. jaundice 3 categoriespre-hepatic (unconjugated — hemolysis, Gilbert) + hepatic (mixed — hepatocellular damage) + post-hepatic / cholestatic (conjugated — extrahepatic obstruction or intrahepatic cholestasis)
  8. cholestatic pattern clinical featuresALP + GGT elevation + direct bilirubin + pruritus (bile acids in skin) + dark urine + pale stool + fat-soluble vitamin malabsorption (ADEK)
  9. acute hepatitis ALT > 1000 differentialdrug (acetaminophen most common) + viral (HAV/HBV/HCV/HEV) + autoimmune (rare this high) + ischemic (“shock liver”) + Wilson fulminant + HSV hepatitis + Budd-Chiari
  10. non-invasive fibrosis assessment 2024FIB-4 score (age + AST + ALT + platelets) for population screening → FibroScan (transient elastography) or MR elastography (most accurate) → biopsy for discordant cases; replacing routine biopsy in many situations