liver

Introduction to Liver Diseases

• Overview of liver diseases.
• Focus on liver only (previously included gallbladder and pancreatic diseases).

Anatomy and Physiology of the Liver

Location and Structure

• Right upper quadrant of the body.
• Composed of two main lobes with eight sections and numerous lobules.

Blood Supply

• Hepatic Artery: Delivers oxygen-rich blood to the liver.
• Hepatic Portal Vein: Brings nutrient-rich blood from the digestive tract.
• Importance of blood supply highlighted in complications related to liver disease.

Functions of the Liver

• Holds approximately one pint of blood; relevance to abdominal wound bleeding.
• Primary Functions:
  • Detoxification: Removes toxins and byproducts from drugs and chemicals, leading to discussions on hepatotoxicity.
  • Nutritional Regulation: Prevents shortages of vitamins and minerals, and stores glucose as glycogen.
  • Metabolism: Plays a role in food metabolism for energy production.
  • Immune Function: Filters bacteria; contributes to fighting infections.
  • Bile Production: Essential for digestion and absorption of fat-soluble vitamins.
  • Coagulation Factor Production: Produces most coagulation factors and proteins including albumin, essential for fluid balance in the circulatory system.

Assessment of Liver Function

Liver Function Tests (LFTs)

• Key components of LFTs:
  • ALT (Alanine Aminotransferase): Normal range is $(7-55)$ units per liter.
  • AST (Aspartate Aminotransferase): Normal range is $(8-48)$ units per liter.
  • ALP (Alkaline Phosphatase): Normal range is $(40-129)$ units per liter.
• Elevated LFTs indicate liver disease, inflammation, or damage.
• Low LFTs could suggest nutritional deficiencies but are not strong indicators of disease.

Bilirubin

• Bilirubin: Byproduct of red blood cell breakdown; normal range is $(0.1-1.2)$ mg/dL.
• High levels indicate liver dysfunction and are associated with jaundice.

Total Protein and Albumin

• Total Protein: Normal range is $(6.3-7.9)$ grams per deciliter.
• Albumin: Values above $(5)$ are desired; below $(2.5)$ indicates malnutrition and potential readiness for hospice care.
• Low albumin levels lead to fluid movement into the extravascular spaces, causing ascites (fluid in the abdomen).

Ammonia Levels

• Normal range for ammonia is $(15-45)$ µg/dL.
• Elevated levels indicate impaired liver function and lead to neurological disorders.

Diagnostic Imaging and Procedures

Ultrasound and Transient Elastography

• Ultrasound: Uses sound waves to visualize liver structure and detect abnormalities.
• Transient Elastography: Measures liver tissue elasticity; harder tissue indicates damage or disease.

Other Imaging Techniques

• CT (Computed Tomography) and MRI (Magnetic Resonance Imaging): Assess liver structure and identify masses or abnormalities.
• Biopsy: Extracts liver tissue for analysis to diagnose diseases, including cancer.

Classification of Liver Diseases

Alcoholic vs. Non-Alcoholic

• Liver diseases classified into two major categories:
  • Alcoholic Liver Disease: Can cause inflammation (hepatitis) with minimal alcohol consumption (~3.5 ounces can initiate processes).
  • Non-Alcoholic Liver Disease: Causes include infections, cancer, and obesity.

Viral Hepatitis

• Types of Viral Hepatitis: A, B, C
  • Hepatitis A: Acute, foodborne (fecal-oral); usually resolves without long-term damage.
  • Hepatitis B: Chronic, bloodborne; can become latent without treatment.
  • Hepatitis C: Chronic, bloodborne; typically progressive and can cause severe damage; difficult to treat.

Additional Causes of Liver Damage

• Toxin- or Drug-Induced: Many medications and environmental toxins can cause liver damage, especially hepatotoxic drugs.
• Autoimmune Disorders: Rare; result in long-term liver damage; often diagnosed based on blood tests for antibodies.
• Fatty Liver Diseases:
  • Nonalcoholic Fatty Liver Disease (NAFLD): Lipid accumulation without damage.
  • Nonalcoholic Steatohepatitis (NASH): Fatty liver with inflammation and damage.

Disease Progression and Stages

Hepatic Steatosis to Cirrhosis

• Progression includes stages:
  • Healthy liver → Hepatic steatosis → NASH → Cirrhosis.
• Cirrhosis: End-stage liver disease characterized by scar tissue development, irreversible damage, and loss of liver function.

Phases of Liver Damage

• Prodromal Phase: Early symptoms resembling flu; potentially reversible.
• Icteric Phase: Visibility of jaundice and itching; treatment may still halt progression.
• Post-Icteric (Recovery) Phase: Potential recovery or return to damage cycles.

Complications Arising from Liver Disease

Systemic Effects

• Portal hypertension due to stiff liver tissue causing venous congestion.
• Risk of hepatic encephalopathy related to toxin accumulation in the blood (especially ammonia).
• Kidney injury due to maladaptive responses to portal hypertension (RAAS system overactivity leading to renal failure).

Symptoms and Clinical Management of Liver Diseases

Symptoms

• Fatigue, jaundice, slow healing wounds, ascites, dry, itchy skin.
• Ascites caused by low albumin leading to fluid leakage.

Treatment Approaches

• Viral Hepatitis: Managed with antivirals depending on the type (A, B, C).
• Autoimmune Cases: Use medications to suppress immune function.
• Lifestyle Adjustments: Emphasis on a healthy diet, moderate alcohol consumption, and avoiding liver irritants.
• Symptom Management: Anti-nausea medications, skin care for itching, and possibly diuretics for fluid management.
• Liver Transplant: Long-term solution for advanced liver diseases; living donor transplants possible due to liver's regenerative abilities.

Conclusion

• Importance of liver health emphasized: appropriate alcohol consumption, nutritional health, and routine check-ups for liver disease risk factors.
• Takeaway message: Be mindful of lifestyle choices to protect liver function and overall health.