Practice 5 structured short- and long-answer medical questions on Liver Histology & Physiology. Review model answers for exam revision.
Answer: ## 1. LIVER HISTOLOGY & PHYSIOLOGY ## Key Points - ### Structural Units - **Lobule** = hexagonal, central vein in middle, portal triads at periphery - **Acinus** = functional unit based on microcirculation - Portal triad contains: **bile duct + hepatic artery + portal vein branch** - Central vein = tributary of hepatic vein - ### Acinar Zones (CRITICAL FOR EXAMS) ⭐ | Zone | Location | Oxygenation | Affected by | |---|---|---|---| | Zone 1 | Periportal | Best | Phosphorus poisoning, eclampsia | | Zone 2 | Midzonal | Intermediate | Yellow fever | | Zone 3 | Centrilobular | Worst | Alcohol, CCl4, ischemia, shock, right heart failure | - ### Liver Functions - Bilirubin metabolism & excretion - Bile acid synthesis (12-36g/day): cholic acid + chenodeoxycholic acid - Secreted as taurine & glycine conjugates - 10-20% deconjugated in ileum → enterohepatic circulation - Functions of bile: 1. - Elimination of water-insoluble bilirubin, excess cholesterol, xenobiotics 2. - Emulsification of dietary fat in gut - ### Pathway - Aging RBCs → Heme → (Heme oxygenase) → Biliverdin → (Biliverdin reductase) → Bilirubin - Bilirubin bound to albumin → liver → conjugated with glucuronic acid (UDP-glucuronosyltransferase) - Bilirubin glucuronides → excreted in bile → gut → urobilinogen → stercobilin (stool) - Some urobilinogen reabsorbed → enterohepatic circulation → excreted in urine ## Detailed Notes ### Structural Units - **Lobule** = hexagonal, central vein in middle, portal triads at periphery - **Acinus** = functional unit based on microcirculation - Portal triad contains: **bile duct + hepatic artery + portal vein branch** - Central vein = tributary of hepatic vein ### Acinar Zones (CRITICAL FOR EXAMS) ⭐ | Zone | Location | Oxygenation | Affected by | |---|---|---|---| | Zone 1 | Periportal | Best | Phosphorus poisoning, eclampsia | | Zone 2 | Midzonal | Intermediate | Yellow fever | | Zone 3 | Centrilobular | Worst | Alcohol, CCl4, ischemia, shock, right heart failure | ### Liver Functions - Bilirubin metabolism & excretion - Bile acid synthesis (12-36g/day): cholic acid + chenodeoxycholic acid - Secreted as taurine & glycine conjugates - 10-20% deconjugated in ileum → enterohepatic circulation - Functions of bile: 1. Elimination of water-insoluble bilirubin, excess cholesterol, xenobiotics 2. Emulsification of dietary fat in gut ## 2. BILIRUBIN METABOLISM ### Pathway - Aging RBCs → Heme → (Heme oxygenase) → Biliverdin → (Biliverdin reductase) → Bilirubin - Bilirubin bound to albumin → liver → conjugated with glucuronic acid (UDP-glucuronosyltransferase) - Bilirubin glucuronides → excreted in bile → gut → urobilinogen → stercobilin (stool) - Some urobilinogen reabsorbed → enterohepatic circulation → excreted in urine ### Jaundice - Bilirubin > **2 mg/dl** → jaundice (yellowish skin + sclera = icterus) - **Kernicterus** = unconjugated bilirubin accumulation in brain → toxic ⭐ ### Causes of Jaundice 1. Excessive production (hemolysis) 2. Reduced hepatocellular uptake 3. Impaired conjugation (Gilbert's, Crigler-Najjar) 4. Decreased hepatocellular excretion 5. Impaired bile flow (cholestasis) ### Types of Bilirubin ⭐ | Feature | Unconjugated | Conjugated | |---|---|---| | Water solubility | Insoluble | Soluble | | Albumin binding | Tight | Loose | | Urine | Absent | Present (tea-colored urine) | | Toxicity | **Toxic** (kernicterus) | Nontoxic | | Lab | Total minus direct | Direct bilirubin | | Cause | Hemolysis, impaired conjugation | Cholestasis, hepatocellular disease | ## 3. LIVER FUNCTION TESTS | Category | Tests | |---|---| | Hepatocyte integrity | AST (SGOT), ALT (SGPT), LDH | | Biliary excretory function | Serum bilirubin, Alkaline phosphatase, GGT | | Hepatocyte synthetic function | Albumin, Prothrombin time, Ammonia | ### Key Points ⭐ - **ALT more specific** for liver than AST - **AST:ALT > 2:1** = alcoholic liver disease ⭐ - ↑↑ Alkaline phosphatase = cholestasis/biliary obstruction - ↓ Albumin + ↑ PT = severe hepatocellular dysfunction - Aminopyrine breath test + galactose elimination = hepatocyte function ## 4. HISTOLOGIC PATTERNS OF HEPATIC INJURY | Pattern | Description | Associated with | |---|---|---| | Steatosis | Fat (neutral fat/TG) in hepatocytes | Alcohol, NAFLD, obesity, drugs | | Ballooning degeneration | Hydropic swelling of hepatocytes | Alcoholic hepatitis, viral hepatitis | | Councilman bodies | Acidophilic apoptotic hepatocytes | Acute viral hepatitis ⭐ | | Mallory bodies | Eosinophilic cytokeratin inclusions | Alcoholic hepatitis ⭐ (also PBC, Wilson's, NASH) | | Piecemeal necrosis | Periportal necrosis | Chronic hepatitis | | Bridging necrosis | Portal-portal or portal-central | Severe hepatitis | | Massive necrosis | Entire lobules | Fulminant hepatitis | | Coagulative necrosis | Mummified hepatocytes, poorly staining | | | Lytic necrosis | Hepatocytes swell and rupture | | | Fibrosis | Portal, central, bridging | Chronic liver disease | | Cirrhosis | Regenerative nodules + fibrosis | End-stage | ## 5. CHOLESTASIS ### Definition - Systemic retention of bilirubin and other solutes eliminated in bile (bile salts, cholesterol) - Results from hepatocellular dysfunction OR intra/extrahepatic biliary obstruction ### Clinical Features - Jaundice - **Pruritis** (bile salts deposited in skin) ⭐ - Skin xanthomas (cholesterol deposits) - Malabsorption (fat-soluble vitamins A, D, E, K) - Pale/clay-colored stools - Dark urine ### Lab - ↑ Bilirubin (conjugated) - ↑↑ Alkaline phosphatase ⭐ - ↑ Lipids - ↑ GGT ### Biopsy Findings - Bile pigment accumulation within hepatic parenchyma - Hepatocyte swelling + foamy degeneration - Bile duct distension + proliferation - Bile lakes (rupture of bile ducts) - Portal tract fibrosis - Cholangitis + cholangiolitis ### Types - **Intrahepatic**: hepatocellular dysfunction - **Extrahepatic**: mechanical obstruction of bile ducts ## 6. HEPATIC FAILURE ### Definition - Loss of **80-90%** of hepatic functional capacity ### Causes 1. **Chronic liver disease** (cirrhosis) — progressive 2. **Massive hepatic necrosis** (fulminant failure): - Viral hepatitis - Drugs: acetaminophen, halothane, rifampicin, MOI antidepressants, CCl4 - Amanita phalloides mushroom toxins 3. **Hepatic dysfunction without necrosis**: - Reye's syndrome - Tetracycline toxicity - Acute fatty liver of pregnancy ### Clinical Consequences Hepatic dysfunction signs: - Jaundice + cholestasis - Hypoalbuminemia → edema, ascites - Hyperammonemia → encephalopathy - Hypoglycemia - Fetor hepaticus (musty odor) - Palmar erythema - Spider angiomas - Hypogonadism + gynecomastia (↓ estrogen metabolism) - Weight loss + muscle wasting - Coagulopathy (↓ clotting factors) Portal hypertension from cirrhosis: - Ascites - Splenomegaly - Hemorrhoids - Caput medusae (abdominal skin) - Esophageal varices Life-threatening complications: - Hepatic failure → multiple organ failure - Coagulopathy - Hepatic encephalopathy - Hepatorenal syndrome - Esophageal varices → rupture → massive GI bleed - Hepatocellular carcinoma ### Prognosis - **80% mortality** ⭐ ## 7. HEPATIC ENCEPHALOPATHY - Metabolic disorder of CNS + neuromuscular system - Associated with severe hepatocellular dysfunction + portosystemic shunting - **Pathogenesis**: ammonia → neuronal dysfunction + generalized brain edema ⭐ - **Asterixis** = flapping tremor = hallmark sign ⭐ ### Clinical Spectrum - Subtle behavioral changes - Confusion → stupor → deep coma → death - Other: rigidity, hyperreflexia, EEG changes, seizures - Minor morphologic changes in brain ## 8. HEPATORENAL SYNDROME - Renal failure in severe liver disease WITHOUT intrinsic kidney disease - Excluded: concomitant liver + kidney damage, ATN secondary to circulatory collapse - Pathogenesis: vasoconstriction → decreased renal blood flow - **Urine**: hyperosmolar, protein-negative, low Na⁺ ⭐ - Lab: ↑ blood urea + creatinine - Px: may hasten death or persist for months ## 9. CIRRHOSIS ### Definition - **Irreversible** end-stage chronic liver disease → parenchymal injury + fibrosis ### 3 Histologic Features ⭐ 1. Bridging fibrous septa 2. Disruption of **entire** liver architecture 3. Parenchymal nodules ### Types | Type | Nodule size | Associated with | |---|---|---| | Micronodular | Uniform, <3mm | **Alcohol** ⭐ | | Macronodular | Variable, >3mm | **Viral hepatitis** ⭐ | | Mixed | Both | | ### Etiologic Classification ⭐ | Cause | % | |---|---| | Alcoholic liver disease | **60-70%** | | Viral hepatitis | 10% | | Biliary diseases | 5-10% | | Primary hemochromatosis | 5% | | Wilson's disease | Rare | | α1-antitrypsin deficiency | Rare | | Cryptogenic | **10-15%** | Others: drugs (α-methyldopa, acetaminophen), Ca, syphilis, galactosemia, tyrosinosis, cardiac cirrhosis ### Pathogenesis - Progressive fibrosis: **collagen types I & III** deposited in all portions of lobule - Key cell: **Ito cell (hepatic stellate cell)** ⭐ - Stimulated by: - Chronic inflammation + cytokines (TNF, IL-1) - Cytokine production by endogenous liver cells - Disruption of extracellular matrix - Direct stimulation of Ito cells by toxins - TGF-β = fibrogenesis ⭐ - Kupffer cells activate stellate cells → release PDGF, TNF, ET-1, TGF-β - → Severe disruption of blood flow + impaired diffusion of solutes ### Clinical Features - May be asymptomatic early - Nonspecific: malaise, anorexia, weight loss, weakness - Jaundice, ascites, peripheral edema - ↑ transaminases, bilirubin, alk. phosphatase - ↓ albumin, clotting factors, Hb - Advanced: frank debilitation → hepatic failure ### Prognosis — Death from: ⭐ 1. Progressive hepatic failure 2. Portal hypertension complications 3. Hepatocellular carcinoma ## 10. PORTAL HYPERTENSION ### Definition - Increased resistance to portal blood flow (normal portal pressure = 5-10 mmHg) ### Causes ⭐ | Level | Cause | |---|---| | Pre-hepatic | Portal vein thrombosis, massive splenomegaly | | Hepatic | **Cirrhosis** (most common) | | Post-hepatic | Severe Rt heart failure, constrictive pericarditis, hepatic vein outflow obstruction | ### Mechanisms in Cirrhosis - Increased resistance to portal blood flow in sinusoids - Compression of central veins by perivenular fibrosis + expanding parenchymal nodules - Arterio-portal anastomoses in fibrous bands ### 4 Major Consequences ⭐ 1. **Ascites** 2. **Portosystemic venous shunts** 3. **Congestive splenomegaly** 4. **Hepatic encephalopathy** ### Portosystemic Shunt Sites ⭐ | Site | Result | |---|---| | Cardioesophageal junction | **Esophageal varices** (most dangerous — rupture = massive bleed) ⭐ | | Rectum | **Hemorrhoids** | | Falciform ligament | **Caput medusae** (periumbilical veins) ⭐ | | Retroperitoneum | Retroperitoneal varices | ### Ascites - Excess serous fluid in abdominal cavity - Fluid: albumin, solutes, few mesothelial cells, mononuclear leukocytes - **Neutrophils = secondary infection (SBP)** ⭐ - Hydrothorax can occur Pathogenesis: 1. Sinusoidal hypertension → ↑ hydrostatic pressure + hypoalbuminemia 2. Percolation of hepatic lymph into peritoneal cavity 3. Renal Na⁺ + water retention (secondary hyperaldosteronism) ### Splenomegaly - Congestive splenomegaly, may be massive - **Hypersplenism** → excessive removal of blood elements: - Anemia - Leukopenia - **Thrombocytopenia** ⭐ (most clinically significant) ## 11. VIRAL HEPATITIS ### Hepatotropic Viruses ⭐ | Feature | HAV | HBV | HCV | HDV | HEV | |---|---|---|---|---|---| | Type | ssRNA | **dsDNA** | ssRNA | ssRNA (defective) | ssRNA | | Incubation | 2-4 wks | 4-26 wks | 2-26 wks | Same as HBV | 2-8 wks | | Transmission | **Fecal-oral** | Parenteral, sexual, vertical | **Parenteral** (IV drug) | Parenteral (needs HBV) | **Fecal-oral** | | Chronicity | **Never** | 5-10% adults | **85%** ⭐ | Yes | **Never** | | Carrier | No | Yes | Yes | Yes | No | | HCC | No | **Yes** | Yes | No | No | | Fulminant | Rare | Rare | Very rare | **Yes (superinfection)** ⭐ | **Yes (pregnant)** ⭐ | | Vaccine | Yes | Yes | No | HBV vaccine protects | No | ### Other Viral Hepatitis - EBV, CMV, HSV, Arbovirus (Yellow fever), Rubella, Adenovirus, Enterovirus ### HBV Serology ⭐ (MUST KNOW) | Marker | Significance | |---|---| | HBsAg | Active infection (acute or chronic) | | Anti-HBs | Recovery + immunity; also post-vaccination | | HBeAg | Active replication, HIGH infectivity | | Anti-HBe | Low infectivity | | HBcAg | NOT in serum (only liver) | | Anti-HBc IgM | **Acute infection** ⭐ | | Anti-HBc IgG | Past infection | | **Window period** | HBsAg gone, Anti-HBs not yet → only Anti-HBc IgM positive ⭐ | ### HBV → HCC Mechanism ⭐ - HBV genome has NO oncogenic sequences - No selective integration site - Repeated cell death + regeneration → genomic instability + mutations - **HBx protein** = transcriptional activator → activates proto-oncogenes ⭐ - HBV proteins bind + **inactivate p53** ⭐ ### Clinical Syndromes of Viral Hepatitis
Answer: Model answer pending
Answer: Model answer pending
Answer: Histology of Acute Hepatitis: - Ballooning degeneration - Cholestasis (bile plugs) - Steatosis (HCV) ⭐ - Hepatocyte necrosis: - Dropped out cells surrounded by macrophages = **Councilman bodies** ⭐ - Apoptotic cells - Kupffer cell hypertrophy + hyperplasia - Portal tracts infiltration → spill over = interface hepatitis Prognosis of Acute Hepatitis: - HBV: 1% fulminant; 5-10% chronic hepatitis - HCV: 85% chronic hepatitis; 15% resolution ⭐ **4. Chronic Hepatitis** (>6 months) - Symptomatic, biochemical or serologic evidence of continuing/relapsing hepatic disease - **Histology:** - Portal inflammation (mildest form) - Piecemeal necrosis (periportal) — more severe - Bridging inflammation + necrosis - Bile duct epithelial proliferation - **Lymphoid aggregates** (HCV specific) ⭐ - Fibrosis (portal, periportal, bridging) - → Cirrhosis - Lab: ↑ PT, bilirubin, alk. phosphatase; ↓ globulins - Px: highly variable
Answer: ### Autoimmune Hepatitis ⭐ - Chronic hepatitis, histologically indistinguishable from chronic viral hepatitis - **Female predominance (70%)** ⭐ - No serologic viral markers - ↑ serum IgG > 2.5 g/dl - High titers autoantibodies (80%): **ANA, anti-smooth muscle** ⭐ - Increased HLA-B8 or HLA-DRw - 60% have other autoimmune diseases (RA, Sjogren's) - Overall risk of cirrhosis: **5%** - Rx: **good response to immunosuppressive therapy** ⭐ ## 12. ALCOHOLIC LIVER DISEASE ### Overview - Alcohol = 5th leading cause of death in USA - Effects on: liver, GIT (ulcers, gastritis), CNS (peripheral neuropathy, Wernicke-Korsakoff), CVS (cardiomyopathy, hypertension), pancreas (pancreatitis), pregnancy (fetal alcohol syndrome) - **3 forms** (can coexist/overlap): 1. Hepatic steatosis 2. Alcoholic hepatitis 3. Alcoholic cirrhosis ### Pathogenesis of Alcohol-Induced Liver Damage Steatosis mechanism: 1. Generation of excess **NADH** by alcohol dehydrogenase + acetaldehyde dehydrogenase → ↑ lipid biosynthesis 2. Impaired assembly + secretion of lipoproteins 3. Increased peripheral catabolism of fat Hepatocellular damage mechanism: 1. Induction of cytochrome P-450 → free radicals 2. Generation of reactive oxygen species 3. Direct effect on microtubular + mitochondrial function + membrane fluidity 4. **Acetaldehyde** → lipid peroxidation + acetaldehyde-protein adducts → disrupts cytoskeletal + membrane function ⭐ 5. Antigenic alteration of hepatocytes → immunologic attack **Alcohol-induced fibrosis:** Multifactorial, poorly understood Other mechanisms: - Malnutrition + vitamin deficiencies - Impaired digestive function (chronic gastric + intestinal mucosal damage + pancreatitis) ### A. Hepatic Steatosis - Lipid droplets accumulate in hepatocytes - 2 histologic types: **Microvesicular + Macrovesicular** ⭐ - Initially **centrilobular** → later panlobular - Grossly: large (4-6 kg), soft, **yellow greasy liver** ⭐ - **Completely reversible with abstinence** ⭐ - Clinically: asymptomatic; mild ↑ bilirubin + alk. phosphatase ### B. Alcoholic Hepatitis - Hepatocyte swelling (**ballooning**) due to fat + water accumulation + cell necrosis - **Mallory bodies** = characteristic eosinophilic cytoplasmic inclusions (cytokeratin intermediate filaments) ⭐ - Neutrophilic reaction - Fibrosis - Clinically: minimal to severe manifestations; ↑ bilirubin, alk. phosphatase, WBCs ### C. Alcoholic Cirrhosis - Initially: yellow-tan, fatty, enlarged liver - Eventually: brown, shrunken, non-fatty - **Micronodular** pattern ⭐ - Fibrous septa become thicker + extend through sinusoids - Regenerative nodules with entrapped hepatocytes ### Clinical Features of Alcoholic Liver Disease - **Steatosis:** Asymptomatic, mild ↑ bilirubin + alk. phosphatase - **Hepatitis:** Minimal to severe; ↑ bilirubin, alk. phosphatase, WBCs - **Cirrhosis:** Similar to other forms of cirrhosis ### Prognosis ⭐ - 5-yr survival approaches **90% in abstainers** (free of jaundice, ascites, hematemesis) - Drops to **50-60%** in those who continue drinking - Immediate causes of death: 1. Hepatic failure 2. Massive GI hemorrhage 3. Intercurrent infection 4. Hepatorenal syndrome 5. Hepatocellular carcinoma ## 13. NAFLD (Non-Alcoholic Fatty Liver Disease) - Most common metabolic liver disease ⭐ - Most common cause of incidental elevation of serum transaminases - Fatty liver in individuals who **do NOT drink alcohol** - May present as steatosis OR **NASH** (nonalcoholic steatohepatitis) — similar to ASH histologically ⭐ - Significant contributor to cryptogenic cirrhosis ### Associated Conditions ⭐ - **Type 2 Diabetes Mellitus** - **Obesity** - **Dyslipidemia** (↑ TG, ↓ HDL, ↑ LDL) - **Insulin resistance** (consistent association) ⭐ ### Pathogenesis - Insulin resistance → TG accumulation in hepatocytes - Fat-laden hepatocytes → sensitive to lipid peroxidation → liver damage + inflammation - Steatosis patients: **asymptomatic** - NASH patients: may have fatigue, malaise, RUQ discomfort, or symptoms of chronic liver disease ### Prognosis - Progression from steatosis → NASH → cirrhosis is **LOW frequency** ⭐ ## 14. METABOLIC LIVER DISEASES ### A. Hemochromatosis ⭐ (MUST KNOW) - Most common inherited liver disease - **Autosomal recessive** - **HFE gene mutation** (chromosome 6) ⭐ - Excessive iron absorption → iron deposits in multiple organs Organs affected: - Liver → **cirrhosis** - Pancreas → **diabetes** ("bronze diabetes") ⭐ - Heart → cardiomyopathy - Skin → bronze pigmentation - Joints → arthropathy - Pituitary/gonads → hypogonadism **Classic Triad: Cirrhosis + Diabetes + Bronze skin** ⭐ Lab: - ↑ Serum iron - ↑ Ferritin - ↑ Transferrin saturation (>50%) ⭐ - ↓ TIBC - Stain: **Prussian blue** (hemosiderin) ⭐ **Complications:** Cirrhosis, HCC (200x risk ⭐), diabetes, cardiomyopathy, hypogonadism **Rx:** **Phlebotomy** (weekly) ⭐ **Secondary hemochromatosis:** Multiple transfusions, hemolytic anemias ### B. Wilson's Disease ⭐ - **Autosomal recessive** - Defect in **copper-transporting ATPase** (chromosome 13) ⭐ - Copper accumulates in: **liver, brain, eye, kidney** Clinical: - **Kayser-Fleischer rings** = copper deposits in cornea ⭐ - Liver: hepatitis → cirrhosis - Brain: basal ganglia degeneration → neuropsychiatric symptoms - Hemolytic anemia - Renal tubular dysfunction (Fanconi syndrome) Lab: - ↓ Serum ceruloplasmin ⭐ - ↑ Urine copper - ↑ Liver copper (biopsy) **Dx:** Liver biopsy + copper quantification **Rx:** **D-penicillamine** (copper chelation) ⭐ ### C. Alpha-1 Antitrypsin Deficiency ⭐ - **Autosomal recessive** - AAT = protease inhibitor produced by liver - Deficiency → two effects: 1. **Emphysema** (lungs unprotected from neutrophil elastase) ⭐ 2. **Cirrhosis** (liver accumulates abnormal misfolded AAT) - Histology: **PAS-positive, diastase-resistant globules** in hepatocytes ⭐ - Major cause of neonatal cholestasis (15%) ⭐ - Rx: Liver transplantation ### D. Reye's Syndrome ⭐ - Children given **aspirin** during viral illness (influenza/varicella) - Mitochondrial dysfunction - **Microvesicular steatosis** of liver - Hypoglycemia, hyperammonemia - **Encephalopathy WITHOUT jaundice** ⭐ - High mortality - **Aspirin now contraindicated in children** ⭐ ## 15. INFLAMMATORY LIVER DISEASE (INFECTIONS) ### Pathways of Liver Infection 1. Arterial supply (bacteremia) 2. Portal vein (pylephlebitis) 3. Ascending biliary infection 4. Direct liver invasion from nearby organ 5. Penetrating injury ### Organisms - **Bacterial:** Staphylococcal bacteremia, salmonellosis, miliary TB - **Viral:** EBV, CMV, HSV, Arbovirus (Yellow fever), Rubella, Adenovirus, Enterovirus - **Protozoal:** Malaria, amebiasis, echinococcus ⭐ ### Liver Abscess ⭐ - **Pyogenic:** E. coli, Klebsiella (from portal pyemia/pylephlebitis) - **Amoebic:** Entamoeba histolytica → **"anchovy paste" pus** ⭐ - Multiple liver abscesses → pylephlebitis ⭐ ## 16. TUMORS OF THE LIVER ### Classification Benign: - Non-neoplastic: Cysts (simple, congenital, choledochal, polycystic), focal nodular hyperplasia - Neoplastic: **Hemangioma** (most common), adenoma Malignant: - Primary: HCC, cholangiocarcinoma - Secondary: metastatic (most common hepatic malignancy overall) ⭐ ### Most Common Benign: Cavernous Hemangioma ⭐ - Most common benign liver tumor - Usually incidental finding - **Do NOT biopsy** (risk of massive hemorrhage) ⭐ ### Focal Nodular Hyperplasia (FNH) - **Central stellate scar** ⭐ - NOT associated with OCPs - No malignant potential - No rupture risk ### Liver Cell Adenoma ⭐ - Mostly in **young women on OCPs** ⭐ - Well-demarcated yellow-tan, bile-stained nodule - May reach up to 30 cm - Histology: sheets + cords of cells resembling normal hepatocytes, minimal pleomorphism, **no portal tracts** ⭐ - Clinical significance: 1. Misdiagnosed as HCC 2. May **rupture → serious intraabdominal hemorrhage** ⭐ - **May regress on stopping OCPs** ⭐ ### Adenoma vs FNH ⭐ | Feature | Adenoma | FNH | |---|---|---| | OCP association | **Yes** | No | | Rupture risk | **Yes** | No | | Malignant potential | Low | **None** | | Central scar | No | **Yes** ⭐ | | Portal tracts | Absent | Present | ### Hepatocellular Carcinoma (HCC) ⭐ - Malignant tumor from hepatocytes - Wide geographic variation - **M:F = 3:1 to 8:1**; adulthood - **HCC frequently associated with cirrhosis** - **Chronic HBV carrier = 200x increased risk** ⭐ Risk Factors: - Viruses: HBV, HCV - Chemicals: alcohol, food hepatocarcinogens (**Aspergillus flavus aflatoxin B1**) ⭐ - Chronic liver disease (cirrhosis) HBV Mechanism: - HBV genome has NO oncogenic sequences - Repeated cell death + regeneration → genomic instability - **HBx protein** = transcriptional activator → activates proto-oncogenes ⭐ - HBV proteins bind + **inactivate p53** ⭐ Pathology: - Unifocal, multifocal, or diffusely infiltrative - Cirrhosis of surrounding parenchyma frequently present - **Strong propensity for vascular invasion** ⭐ (portal vein, hepatic vein) - Histology: well-differentiated to anaplastic - Well-diff: resembles hepatocytes, may show intracytoplasmic bile globules - **Fibrolamellar variant:** better prognosis, young patients, no cirrhosis ⭐ Clinical Features: - Asymptomatic hepatomegaly - In cirrhosis: rapid ↑ liver size, sudden worsening ascites, **bloody ascites**, fever + pain - Lab: **AFP > 1000 ng/ml highly suggestive** ⭐ - AFP = nonspecific tumor marker Prognosis: - Grim: death within **6 months - 1 year** from: 1. Severe cachexia 2. GI bleeding 3. Liver failure 4. Tumor rupture - **Rx: complete surgical resection** ⭐ ### Cholangiocarcinoma ⭐ - Malignant epithelial neoplasm of bile duct origin - Less common than HCC - **NOT associated with HBV/HCV** ⭐ - AFP normal Etiology: - Majority: no known risk factor - Radiologic contrast material: **Thorotrast** ⭐ - **Opisthorchis sinensis** infestation of biliary tract ⭐ - **Primary sclerosing cholangitis** ⭐ ### HCC vs Cholangiocarcinoma ⭐ | Feature | HCC | Cholangiocarcinoma | |---|---|---| | Origin | Hepatocytes | Bile duct epithelium | | HBV/HCV | **Yes** | **No** | | AFP | ↑↑ | Normal | | Risk factors | Cirrhosis, HBV, aflatoxin | PSC, Opisthorchis, Thorotrast | ### Other Primary Malignant Tumors - **Hepatoblastoma:** Aggressive tumor of **children** ⭐ - **Angiosarcoma:** Association with **vinyl chloride, arsenic + Thorotrast** ⭐ - Primary lymphomas, sarcomas ### Metastatic Tumors ⭐ - **Most common hepatic malignancy** overall - Sources: **colon > lung > breast** ⭐ - May be single or multiple - Asymptomatic or symptomatic ## 17. CIRCULATORY DISORDERS OF THE LIVER ### Classification 1. Impaired blood flow **into** the liver - Hepatic artery inflow - Portal vein obstruction 2. Impaired blood flow **through** the liver - Passive congestion + centrilobular necrosis - Peliosis hepatis 3. Hepatic venous **outflow** obstruction - Budd-Chiari syndrome - Veno-occlusive disease ### A. Impaired Blood Inflow Hepatic Artery Obstruction: - Causes: Thrombosis, embolism, vascular disease (polyarteritis nodosa), compression by neoplasia, sepsis - **Liver infarcts are RARE** due to double blood supply ⭐ - Interruption of main hepatic artery does NOT always produce ischemic necrosis (accessory vessels + portal venous system compensate) - When infarcts occur: small + localized; complete organ loss rare Portal Vein Obstruction: *Extrahepatic causes:* - Peritoneal sepsis + subsequent pylephlebitis - Lymphatic metastasis with enlarged hilar LN - Pancreatitis with splenic vein thrombosis - Hypercoagulability; post-surgical thromboses - **Banti's syndrome:** subclinical portal vein thrombosis due to neonatal omphalitis OR umbilical vein catheterization → fibrotic partially recanalized blood vessel ⭐ *Intrahepatic causes:* - Cirrhosis - Vascular invasion by cancer in liver - Hypercoagulable states Infarct of Zahn ⭐: - Sharply demarcated area of red-blue discoloration - Due to hepatocellular atrophy secondary to marked sinusoidal congestion - **NOT a true infarct** ⭐ - Caused by obstruction of portal vein or its radicles Clinical Manifestations of Portal Vein Obstruction: - Symptoms are variable - Portal hypertension (ascites, esophageal varices, splenomegaly) - Intestinal congestion + pain - Bowel infarction if visceral blood flow impaired - **Multiple liver abscesses** (in pylephlebitis) ⭐ ### B. Impaired Blood Flow Through the Liver Causes: 1. **Cirrhosis:** portal blood flow obstruction due to compression of sinusoids + central veins → increased resistance at sinusoidal level 2. **Physical occlusion of hepatic sinusoid:** Sickle cell anemia 3. **Systemic circulatory compromise:** DIC - Eclampsia of pregnancy: associated with DIC → may result in extensive **subcapsular hepatic hematoma** Passive Congestion + Centrilobular Necrosis: - Manifestations of systemic circulatory collapse - **Right-sided heart failure** → passive congestion → **centrilobular congestion** ⭐ - **Left-sided heart failure/shock** → hepatic hypoperfusion + hypoxia → **centrilobular necrosis** ⭐ - **Combined Rt + Lt heart failure** → **centrilobular hemorrhagic necrosis = "Nutmeg liver"** ⭐ - **Cardiac sclerosis ("cardiac cirrhosis"):** centrilobular fibrosis → uncommon complication of sustained severe CHF ⭐ Peliosis Hepatis ⭐: - **Rare condition:** sinusoidal dilation → blood-filled cavities within hepatic parenchyma - **Associated with:** - Anabolic steroids, OCPs, corticosteroids, danazol ⭐ - Marasmus, bacterial endocarditis, lymphoproliferative disease - **AIDS: Bacillary angiomatosis** caused by **Rochalimaea (Bartonella) henselae** ⭐ - Unknown pathogenesis - **Usually asymptomatic** ⭐ - Complications of advanced peliosis: - Intraabdominal hemorrhage - Hepatic failure ### C. Hepatic Venous Outflow Obstruction Budd-Chiari Syndrome (Hepatic Vein Thrombosis) ⭐: *May be:* - Acute: **usually fatal** ⭐ - Subacute - Chronic *Associated with:* ⭐ - Polycythemia vera - Pregnancy - Post-partum state - Oral contraceptive use - **Paroxysmal nocturnal hemoglobinuria (PNH)** ⭐ - Intraabdominal cancers, particularly **HCC** ⭐ - **30% of cases are idiopathic** ⭐ *Clinical Manifestations:* - Hepatomegaly - Ascites - Abdominal pain + distension - Jaundice - Death *Pathology:* - Thrombosis in major hepatic veins or **inferior vena cava** ⭐ - Swollen **red-purple liver** with tense capsule ⭐ - Severe hepatic centrilobular congestion + necrosis - Centrilobular fibrosis in chronic cases *Prognosis:* - Acute form: **high mortality** ⭐ - Rx: **surgical** ⭐ Veno-Occlusive Disease: *Associated with:* - Drinking **Pyrrolizidine alkaloid-containing bush tea** ⭐ - **Bone marrow transplantation** followed by graft-versus-host disease: - Up to **25% of allogeneic BMT patients** ⭐ - **30% mortality rate** ⭐ - Chemotherapy + radiotherapy induced toxic endothelial injury *Pathology:* - Small hepatic vein radicles obliterated by **subendothelial swelling + collagen deposition** - **Clinically indistinguishable from Budd-Chiari syndrome** ⭐ - Centrilobular congestion + necrosis +/- sclerosis ### Budd-Chiari vs Veno-Occlusive ⭐ | Feature | Budd-Chiari | Veno-occlusive | |---|---|---| | Vessels | Major hepatic veins/IVC | Small hepatic vein radicles | | Pathology | Thrombosis | Subendothelial swelling + collagen | | Causes | Hypercoagulable, OCPs, PNH, HCC | Bush tea, BMT, chemo/radiotherapy | | Clinical | **Indistinguishable from each other** ⭐ | | ## 18. INTRAHEPATIC BILIARY TRACT DISEASE ### Classification Due to general liver disease: - Drug toxicity - Viral hepatitis - Liver transplantation Due to biliary tract disease: - Biliary cirrhosis (Primary + Secondary) - Primary Sclerosing Cholangitis ### Primary Biliary Cirrhosis (PBC) ⭐ - **Autoimmune** disease - Lymphocyte-mediated destruction of **intrahepatic** bile duct epithelium - Chronic progressive + often fatal cholestatic liver disease - Characterized by destruction of intrahepatic bile ducts + portal inflammation + scarring - Primary feature: **nonsuppurative granulomas** ⭐ Demographics: - **Middle-aged women** (onset 20-80 yrs) ⭐ - Insidious onset Clinical Course: - Pruritis (early) → later jaundice appears - Cirrhosis + hepatic failure develops over **2 or more decades** ⭐ - Signs of portal hypertension + hepatic encephalopathy Lab: - ↑ Alk. phosphatase + cholesterol - Bilirubin = **late development** indicating hepatic decompensation ⭐ Autoantibody: - **Anti-mitochondrial Ab in >90% of patients** ⭐ - Target: mitochondrial pyruvate dehydrogenase ⭐ Associated Extra-hepatic Conditions: - Sjogren's syndrome - Scleroderma