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Liver+Pathology+Part+I

The Liver

Liver Function Tests (LFTs)

  • Definition: A group of laboratory tests to analyze liver performance in both normal and disease states.

Key Enzymes and Proteins in LFTs:

  • Aspartate Aminotransferase (AST):

    • Elevation linked to conditions like cirrhosis, hepatitis, hepatic necrosis, and obstructive disease.

  • Alanine Aminotransferase (ALT):

    • More specific than AST for liver function assessment.

    • Remains elevated longer than AST.

    • Elevation associated with conditions such as cirrhosis, hepatitis, pancreatitis, and biliary obstruction.

  • Alkaline Phosphatase (ALP):

    • Significant elevation indicates obstructive jaundice, hepatic carcinoma, abscess, or cirrhosis.

  • Alpha-Fetoprotein:

    • Protein made by the liver, yolk sac, and GI tract, increases in hepatocellular carcinoma, liver metastasis, and childhood hepatoblastoma.

  • Lactic Acid Dehydrogenase (LDH):

    • Mildly elevated in hepatitis, cirrhosis, and obstructive jaundice.

  • Gamma Glutamyl Transpeptidase (GGT):

    • Elevated in diseases causing acute liver damage and bile duct issues.

Additional Tests:

  • Prothrombin Time (PT):

    • Measures the time it takes for blood to coagulate (normal: 10 to 15 seconds).

    • Increased in liver disease with cellular damage.

  • Serum Albumin:

    • Decrease indicates reduced protein synthesis.

Bilirubin:

  • General Information:

    • Product of hemoglobin breakdown from red blood cells.

  • Indirect Bilirubin (Unconjugated):

    • Elevation indicates increased red blood cell destruction (e.g., anemias), typically non-obstructive.

  • Direct Bilirubin (Conjugated):

    • Elevation indicates obstructive jaundice from stones/neoplasm obstructing ducts.

Liver Disease and Conditions

Diffuse Liver Disease:

  • Description: Affects hepatocyte function, resulting in decreased liver function, treated medically.

  • Examples: Fatty infiltration, acute and chronic hepatitis, alcoholic liver disease, chronic cirrhosis.

Fatty Liver Disease (Hepatic Steatosis):

  • Definition: Acquired reversible disease with fat deposits within liver cells.

  • Common Causes: Obesity, alcohol abuse, diabetes mellitus.

  • Signs/Symptoms: Typically asymptomatic; may present with jaundice, nausea, vomiting, and abdominal tenderness or pain. Elevated liver function tests may occur.

Imaging Features:

  • Diffuse Fatty Infiltration:

    • Liver appears diffusely echogenic, difficult to penetrate, comparison to kidney helpful for diagnosis.

  • Focal Fatty Infiltration:

    • Affected liver segments appear hyperechoic like a solid mass, challenging to diagnose as may mimic lesions.

Hepatitis:

  • Definition: Inflammation of the liver may develop into cirrhosis, portal hypertension, and hepatocellular carcinoma (HCC).

  • Causes: Viral, bacterial infections or non-infectious causes (medications, toxins, autoimmune disorders).

  • Types: Acute or chronic forms, commonly A, B, C. Healthcare workers at risk for Hepatitis B and C.

Symptoms of Hepatitis:

  • Fever, chills, nausea, vomiting, fatigue, hepatosplenomegaly, dark urine, jaundice.

Chronic Hepatitis:

  • Description: Clinical or biochemical evidence of inflammation lasting longer than 6 months.

  • Sonographic Findings: Coarse, hyperechoic liver texture, possible fibrosis, does not increase in size, may appear small.

Cirrhosis:

  • Definition: Chronic liver damage leading to hepatocyte death, fibrosis, necrosis, resulting in regeneration nodules.

  • Most Common Cause: Chronic alcohol abuse (micronodular) or chronic viral hepatitis (macronodular).

  • Clinical Symptoms: Hepatomegaly, jaundice, ascites, abnormal liver function tests.

  • Sonographic Features: Early signs include hepatomegaly; advanced stages show a decreased right lobe size and increased echo texture derived from fibrosis.

Portal Hypertension:

  • Definition: Elevation of blood pressure within the portal venous system, normal range is 5-10 mmHg, >10 mmHg indicates hypertension.

  • Causes: Commonly due to cirrhosis, other causes include portal vein thrombosis or tumors.

  • Clinical Findings: Asymptomatic initially, can present with upper GI hemorrhage due to varice rupture, ascites, hepatomegaly, jaundice.

  • Sonographic Findings: Includes splenomegaly, ascites, portal-systemic venous collaterals.

Transjugular Intrahepatic Portal-systemic Shunt (TIPS):

  • Purpose: Alleviate portal hypertension.

  • Procedure: Placement of a stent between right portal veins and hepatic veins.

  • Sonographic Findings: Echogenic walls and anechoic lumen, flow velocities indicate patency.

Portal Vein Thrombosis:

  • Definition: Clot development within the portal vein leads to collaterals and potential cavernous formation.

  • Causes: Conditions like hepatocellular carcinoma, pancreatitis, and more.

  • Sonographic Characteristics: Initial difficulty in visualizing clot, with subsequent echogeneity changes occurring.

Budd-Chiari Syndrome:

  • Definition: Occlusion of hepatic veins, can be caused by various factors including tumor invasion and coagulation disorders.

  • Clinical Symptoms: Include ascites, right upper quadrant pain, hepatomegaly.

  • Sonographic Features: Non-visualization of hepatic veins, thrombus presence, enlarged caudate lobe, lack of flow in hepatic veins.