1. Evaluation of Liver Injury
Mark J. Czaja
Liver Research Center
Albert Einstein College of Medicine Bronx, N.Y.

2. Liver Function Tests Alanine aminotransferase (ALT)
Aspartate aminotransferase (AST)
Lactate dehydrogenase (LDH)
Alkaline phosphatase
Bilirubin
Albumin
Really tests indicating injury and not necessarily function.
Ideal test would be highly specific and sensitive.
No test fulfills that criteria.

3. Mechanisms of Liver Dysfunction
Direct cellular injury
Blockage in bile flow
Impaired blood flow

4. Direct Cellular Injury - HCV Infection

5. Blockage in Bile Flow - Biliary Atresia

6. Impaired Blood Flow - CHF

7. Consequences of Liver Injury
liver cell injury
liver cell death
proliferation
matrix deposition
sufficient
inadequate
altered architecture
recovery
liver failure
cirrhosis

8. Types of Liver Tests True tests of liver function
Biochemical markers of liver injury
Biochemical markers of specific liver diseases

9. Testable Biochemical Liver Function
Ability to transport organic anions
Capacity to metabolize certain substances
Capability to synthesize various proteins

10. Steps in Organic Anion Transport
Delivery and uptake
Metabolic alteration
Secretion and excretion

11. Bilirubin Tetrapyrole Toxic in neonates - kernicterus Derived from:
Senescent RBC (70-80%)
Hemoproteins (20-30%)
Ineffective erythropoiesis

12. Bilirubin Formation heme biliverdin bilirubin
oxygenase
reductase
Transport: hydrophobic due to internal H-bonding
circulates bound to albumin

13. Bilirubin Metabolism Plasma Hepatocyte Bile Alb UCB UCB ligandin
glucuronyl
BMG
BDG
BMG
BDG
transferase
BMG
BDG

14. Bilirubin Elimination
Intestine
BMG (20%) + BDG (80%) +UCB (trace)
Deconjugated to urobilinogen
Excreted or reab-sorbed (20%)
Urine
BMG and BDG
No UCB

15. Measurement of Serum Bilirubin
Normal concentration < 1 mg/dl
Conjugated < 5%
Jaundice if > 3 mg/dl
Detected by diazo reaction - cleaved to colored azo-dipyrole
Conjugated reacts rapidly (direct)
Unconjugated reacts slowly (indirect)

16. Differential Diagnosis I
Prehepatic
Intrahepatic
Congenital
Acquired
Posthepatic

17. Differential Diagnosis II
Unconjugated hyperbilirubinemia
Increased bilirubin production (hematological)
Decreased uptake (drug)
Decreased conjugation (congenital)
Conjugated hyperbilirubinemia
Congenital
Drug
Liver disease
Biliary obstruction

18. Inherited Disorders Causing Unconjugated Hyperbilirubinemia
Crigler-Najjar syndrome
Type 1 – absent GT
Type 2 – reduced GT activity
Gilbert’s syndrome – reduced GT activity due to genetic defect in TATAA element of GT promoter

19. Inherited Disorders Causing Conjugated Hyperbilirubinemia
Dubin-Johnson syndrome – mutations in multidrug resistance associated protein 2 (MRP2)
Rotor’s syndrome – genetic defect

20. Hepatic Metabolic Capacity
Clearance must depend on total functional mass or metabolic activity
Hepatic drug metabolism - [14C]amino-pyrine breath test
Galactose elimination
Not used clinically

21. Hepatic Synthetic Capacity
Most major plasma proteins are made in the liver
Decreased hepatocytes = decreased protein synthesis and release
Albumin and coagulation factors are clinically important

22. Albumin 50% of all synthesized hepatic protein
Determinant of plasma oncotic pressure
Important transport protein

23. Serum Albumin Levels Long half-life of 20 days
Large hepatic synthetic reserve
Decreased with persistent, large injury
Decreased in chronic liver disease
Poor prognostic sign

24. Non-hepatic Causes of Hypoalbuminemia
Severe malnutrition
Renal or GI loss
Glomerulopathy, HIV enteropathy
High catabolism
Infections, burns

25. Coagulation Factors Half-lives of hours to days
Liver synthesizes I, II, V, VII, IX, and X
Large synthetic reserve

26. Prothrombin Time (PT)
PT detects abnormalities in I, II, V, VII and X (extrinsic pathway)
PT is increased in liver disease
Best prognostic indicator
Acute liver disease
Chronic liver disease

27. Non-hepatic Causes of Elevated PT
Congenital coagulation factor deficiencies
Consumptive coagulopathies
Vitamin K deficiency (II, VII, IX, X)

28. To Rule Out Vitamin K Deficiency
Any patient with an elevated PT
Parental vitamin K for 3 days
Normalization of PT - vitamin K deficiency
Failure to normalize - hepatocellular disease

29. Serum Immunoglobulins
Not produced by hepatocytes
Frequently elevated in liver disease
Secondary to inflammatory process
? produced by antigen shunting

30. Biochemical Markers of Liver Injury

31. Liver Enzymes Low levels always present in serum
Leak out from cell after injury
Very sensitive
Magnitude of abnormality does not correlate well with degree of injury

32. Aspartate Aminotransferase (AST)
Serum glutamic-oxaloacetic transaminase (SGOT)
Transfers an a-amino group of aspartate to a-keto group of ketoglutaric acid
Present in skeletal muscle, kidney, brain

33. Alanine Aminotransferase (ALT)
Serum glutamic-pyruvic transaminase (SGPT)
Transfers an a-amino group of alanine to a-keto group of ketoglutaric acid
Present principally in liver

34. AST and ALT Elevated in most liver diseases
Highest levels are in acute liver diseases
Only slight elevations in chronic liver diseases
Usually increase in parallel

35. AST/ALT in Alcoholic Hepatitis
Transaminases rarely exceed 300
AST:ALT >2

36. Factors Affecting AST/ALT
Depressed by pyridoxine (vit. B6) deficiency
Decreased by uremia and renal dialysis

37. AST/ALT Controversies
Should lower normal limits be used in females?
Females < 30 vs. males < 40
Are the normal limits too high?
Females < 20 and males < 30

38. Lactate Dehydrogenase (LDH)
Component of classic LFT’s
Highly non-specific

39. Tests of Impaired Hepatic Excretion Increased In
Cholestasis
Intra-hepatic biliary tract obstruction
Extra-hepatic biliary obstruction

40. Alkaline Phosphatase Hydrolyzes phosphate esters at alkaline pH
Also present in bone, kidney, placenta, intestine
Mainly liver and bone in adults
Increased in children from bone growth
Placental form during pregnancy

41. Elevated Alkaline Phosphatase
Can occur in any liver disease
Highest with cholestasis or biliary tract obstruction
Elevated in infiltrative diseases
Due to increase synthesis and secretion

42. Alkaline Phosphatase Isoenzymes
Source
Heat Inactivation
5' NT
GGTP
Liver
Moderate +
Bone
Rapid -
Placenta
Slow
Intestine

43. 5'-Nucleotidase Hydrolyzes 5'- adenosine monophosphate
Mainly present in liver
Increases along with alkaline phosphatase

44. g-Glutamyl Transpeptidase (GGTP)
Transfers g-glutamyl groups
Widely distributed
Sensitive correlate to alkaline phosphatase
Non-specific (alcoholism, MI, DM, pancreatic disease, renal failure)

45. Biochemical Markers of Specific Liver Diseases

46. Etiology-specific Liver Tests
Viral hepatitis serologies
Serum ferritin level
Ceruloplasmin level
Alpha1-antitrypsin level
Antimitochondrial antibody titer

47. Viral Hepatitis Serology
HAV – anti-HAV IgM and IgG
HBV – HBsAg, anti-HBsAg, and anti-HBcAg
HCV – anti-HCV, HCV RNA

48. Serum Ferritin Widely distributed storage protein
Levels reflect body iron stores
Elevated in primary hemochromatosis
Elevated in acute inflammation and cirrhosis

49. Serum Ceruloplasmin Copper-binding protein
Decreased in 95% of patients with Wilson’s disease
20% of heterozygotes have decreased levels

50. a1-Antitrypsin Inhibits serum trypsin Major component of a1-globulin
Deficiency cause of neonatal hepatitis

51. Antimitochondrial Antibody (AMA)
Directed against mitochondrial enzyme pyruvate dehydrogenase complex
Positive in 90% of patients with primary biliary cirrhosis

52. Interpretation of Abnormal LFT’s
Examine multiple tests
Consider non-hepatic causes
Determine the most abnormal tests

53. Hepatocellular vs. Cholestatic
Test
Hepatocellular
Cholestatic
ALT/AST
2-3
NL-1
Alk Phos
Bilirubin
NL-3
Albumin NL PT

54. Case 1
25 yo IVDA c/o 1 week of nausea, vomiting, and myalgias. Physical exam revealed jaundice.
ALT 2045 (15-45)
AST 2300 (15-45)
Alk Phos (50-150)
Bili 3.9 ( )
Alb 4.2 ( )
PT 11.5 (10-12)

55. Hepatocellular W/U H & P EtOH, medications, transfusions
Risk for viral hepatitis
Risk factors
for NASH
Autoimmune features
Etiology-specific LFT’s
USG and liver biopsy

56. HBV Infection - HBcAg Staining

57. Case 2
67 yo c/o several months of weight loss, and 1 week of nausea, vomiting, and myalgias. Physical exam revealed cachexia and jaundice.
ALT 75 (15-45)
AST 115 (15-45)
Alk Phos (50-150)
Bili 10.2 ( )
Alb 4.2 ( )
PT 11.0 (10-12)

58. medications, gallstones, weight loss
Cholestatic W/U
H & P
medications, gallstones, weight loss
USG
normal
dilated ducts
AMA
ERCP
liver biopsy

59. Pancreatic Carcinoma - ERCP