What are the most common causes of liver inflammation?

Most Common Causes of Liver Inflammation

The most common causes of liver inflammation are non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease (ALD), and viral hepatitis, with NAFLD being the leading cause in developed countries affecting 20-30% of the general population. 1, 2

Primary Causes of Liver Inflammation

1. Non-Alcoholic Fatty Liver Disease (NAFLD)

• Prevalence: 20-30% of general population, increasing to 70% with obesity and 90% with diabetes 1
• Spectrum: Ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) 1
• Risk factors:
  • Metabolic syndrome components
  • Obesity
  • Type 2 diabetes
  • Dyslipidemia
  • Insulin resistance 1
• Diagnostic features:
  • AST:ALT ratio typically <1 1
  • Ultrasound shows hepatic steatosis with sensitivity of 84.8% and specificity of 93.6% for moderate-severe steatosis 1

2. Alcohol-Related Liver Disease (ALD)

• Spectrum: Simple steatosis, alcoholic hepatitis, and cirrhosis 1
• Diagnostic features:
  • AST:ALT ratio generally >2 (compared to <1 in NAFLD) 1
  • History of significant alcohol consumption
  • Liver stiffness measurement by transient elastography >12-15 kPa suggests advanced fibrosis 1
• Risk factors:
  • Female gender (increased susceptibility)
  • Obesity (synergistic effect with alcohol)
  • Genetic factors 1

3. Viral Hepatitis

• Types: Hepatitis A, B, C, D, and E 3
• Prevalence: Leading cause of liver inflammation globally 3
• Features:
  • Hepatitis B and C can lead to chronic inflammation
  • Disease burden appears 10-20 years after infection
  • Often presents with right upper quadrant pain, fatigue, and jaundice 2, 3

4. Drug-Induced Liver Injury

• Causes: Medications, dietary supplements, and herbal remedies 2
• Patterns: Can present with hepatocellular or cholestatic patterns of injury 2
• Examples: Methotrexate (risk increases with alcohol consumption) 1

Less Common Causes

• Autoimmune hepatitis
• Hemochromatosis (iron overload)
• Wilson's disease
• Alpha-1 antitrypsin deficiency 1

Synergistic Effects and Co-factors

• HCV + Alcohol: 30-fold increased risk of cirrhosis compared to either alone 2, 4
• Obesity + Alcohol: Obese individuals consuming 15+ drinks weekly have an adjusted relative rate of liver-related death of 18.9 compared to 3.16 in lean counterparts 1
• Metabolic factors: Presence of metabolic syndrome components worsens prognosis in all forms of liver disease 1

Diagnostic Approach

1. Initial laboratory tests:

   • Liver enzymes (ALT, AST, ALP, GGT)
   • Bilirubin
   • Platelet count 1

2. First-line imaging:

   • Ultrasound (sensitivity 84.8% for moderate-severe steatosis) 1

3. Non-invasive fibrosis assessment:

   • FIB-4 score
   • Transient elastography (FibroScan) 1

4. Advanced testing when needed:

   • Liver biopsy (gold standard for NASH diagnosis) 1
   • CT or MRI for further characterization 2

Key Points to Remember

• NAFLD is now the most common cause of chronic liver disease in developed countries 1
• The presence of multiple risk factors (obesity, alcohol, viral hepatitis) has synergistic effects on liver damage 1
• Early identification of the cause is crucial as treatment approaches differ significantly between etiologies 2
• Many patients with liver inflammation are asymptomatic, especially in early stages 5

Understanding these common causes of liver inflammation is essential for proper diagnosis and management, as each etiology requires a specific treatment approach to prevent progression to cirrhosis and its complications.