Liver Dysfunction Flashcards
What are the main physiological functions of the liver?
- Bile secretion (digestion & waste elimination).
- Metabolic functions (regulation of carbohydrates, lipids, proteins, vitamins, iron).
- Detoxification & purification (ureogenesis, xenobiotic metabolism).
- Endocrine function (IGF-1 secretion, vitamin D activation).
- Immune function (Kupffer cells remove endotoxins, viruses, and particles).
What are the main disorders affecting liver function?
- Cholestasis (bile flow obstruction).
- Hepatitis (inflammation, acute/chronic).
- Liver failure (impaired synthetic/catabolic functions).
- Liver cancer (hepatocellular carcinoma, HCC).
What are the key enzymatic markers of liver function?
- Transaminases (ALT, AST) – Indicators of hepatocellular injury.
- Alkaline Phosphatase (ALP), Gamma-Glutamyl Transferase (GGT) – Indicators of cholestasis.
- Lactate Dehydrogenase (LDH) – Marker of hepatocyte necrosis.
- Coagulation factors (Prothrombin Time, Factor V) – Assess synthetic liver function.
How do ALT (ALAT) and AST (ASAT) levels change in liver disease?
- ALT (ALAT) is more liver-specific → High in viral, toxic, or ischemic hepatitis.
- AST (ASAT) also found in muscle & heart → High in alcoholic hepatitis (AST > ALT ratio >2).
What does an increase in GGT and ALP indicate?
- GGT elevation → Alcoholic liver disease, bile duct obstruction.
- ALP elevation → Cholestasis, bile duct disease, or bone disease.
What is the significance of LDH in liver disease?
- LDH5 (Lactate Dehydrogenase 5) is liver-specific.
- Increases in LDH → Hepatocyte necrosis (e.g., viral hepatitis).
What are the non-enzymatic markers of liver function?
- Bilirubin (Total, Direct, Indirect) – Indicator of jaundice.
- Albumin – Reflects synthetic liver function.
- Ammonia (NH₃) – Increased in liver failure (hepatic encephalopathy).
- Blood urea nitrogen (BUN) – Decreased in liver failure (impaired ureogenesis).
- Cholesterol levels – Altered in liver disease (low in cirrhosis, high in cholestasis).
What are the normal bilirubin levels in adults?
- Total Bilirubin (BT): 6-10 mg/L.
- Conjugated Bilirubin (BC): <2 mg/L.
What is cytolytic hepatitis?
It is the destruction of hepatocytes, leading to the release of intracellular enzymes (ALT, AST, LDH).
What are the main causes of cytolytic hepatitis?
- Viral Hepatitis (A, B, C, D, E).
- Autoimmune hepatitis.
- Toxic Hepatitis (drugs, alcohol, toxins).
How do ALT & AST levels change in acute viral hepatitis?
- ALT & AST increase 10-100× normal levels before jaundice appears.
- ALT rises before AST.
What are the laboratory findings in alcoholic hepatitis?
- AST/ALT ratio >2 (AST predominates).
- GGT is significantly elevated.
What is liver cirrhosis?
A chronic, progressive liver disease characterized by fibrosis and loss of function.
What are the types of cirrhosis and their markers?
- Alcoholic Cirrhosis → ↑ GGT, GLD.
- Biliary Cirrhosis → ↑ ALP, GGT, 5’-Nucleotidase.
How does cirrhosis affect enzyme levels in later stages?
- Enzymes stabilize in late-stage cirrhosis despite ongoing damage.
- Coagulation factors & albumin decrease (synthetic function failure).
What are the causes of liver failure (hepatocellular insufficiency)?
- Acute causes: Viral hepatitis, drug toxicity, ischemic injury.
- Chronic causes: Cirrhosis, autoimmune disease, Wilson’s disease.
How does liver failure affect protein metabolism?
- ↓ Albumin → Edema, ascites.
- ↓ Ureogenesis → Hyperammonemia (hepatic encephalopathy).
- ↓ Coagulation factors → Bleeding risk.
What are the metabolic consequences of liver failure?
- Hypoglycemia (impaired glycogen storage).
- Hypocholesterolemia (impaired lipid synthesis)
What is jaundice (icterus)?
A condition where bilirubin accumulates in the blood, causing yellowing of skin & eyes.
What are the three types of jaundice?
- Pre-hepatic (hemolytic jaundice) → ↑ Unconjugated bilirubin (due to hemolysis).
- Hepatic jaundice → Mixed bilirubin increase (due to liver dysfunction).
- Post-hepatic (obstructive jaundice) → ↑ Conjugated bilirubin (due to bile duct obstruction).
What enzymes are elevated in cholestasis (biliary obstruction)?
- ALP (Alkaline Phosphatase).
- GGT (Gamma-Glutamyl Transferase).
- 5’-Nucleotidase
What is Lipoprotein X (LpX), and why is it important?
- Abnormal lipoprotein found in cholestasis.
- Highly specific for bile flow obstruction.
A patient has high ALT, AST, low albumin, and prolonged PT. What is the likely diagnosis?
Acute liver failure (viral hepatitis, toxic injury).
A patient with jaundice and high ALP, GGT, 5’-Nucleotidase likely has?
Cholestasis (biliary obstruction, liver tumor, or gallstones).
