How is alcoholic hepatitis diagnosed?

Diagnosis of Alcoholic Hepatitis

Alcoholic hepatitis is diagnosed through a combination of clinical presentation, laboratory findings, and in cases of diagnostic uncertainty, liver biopsy, with the NIAAA classification system providing a framework for categorizing cases as definite, probable, or possible. 1, 2

Clinical Presentation

• Cardinal sign: Rapid onset of jaundice with associated symptoms 1
• Common symptoms and signs:
  • Fever (even without infection)
  • Malaise and fatigue
  • Tender hepatomegaly
  • Weight loss and malnutrition
  • Signs of decompensation: ascites, hepatic encephalopathy, variceal bleeding 1
  • Spider angioma, palmar erythema, jaundice 1

Alcohol Consumption History

• Minimum thresholds: >40g/day for women, >50-60g/day for men 1
• Duration: Heavy drinking for >5 years, with heavy alcohol use for >6 months 1
• Recent drinking pattern: <60 days of abstinence before onset of jaundice 1

Laboratory Findings

• Liver function tests:

  • Elevated serum bilirubin (>3 mg/dL or >50 μmol/L) 1
  • AST >50 IU/mL but typically <400 IU/mL 1
  • AST/ALT ratio >1.5 (seen in >98% of histologically confirmed cases) 1
  • Hypoalbuminemia (in severe cases) 1

• Hematologic abnormalities:

  • Leukocytosis
  • Macrocytosis
  • Thrombocytopenia
  • Prolonged prothrombin time 1

Diagnostic Algorithm

1. Establish alcohol consumption history meeting minimum thresholds
2. Confirm clinical presentation with jaundice and other symptoms
3. Verify laboratory profile with characteristic AST/ALT ratio >1.5
4. Exclude other causes:
   • Imaging to rule out biliary obstruction
   • Testing for viral hepatitis, autoimmune liver disease, Wilson disease
   • Rule out drug-induced liver injury and ischemic hepatitis 1
5. Apply NIAAA classification:
   • Definite AH: Clinically diagnosed and biopsy-proven
   • Probable AH: Clinically diagnosed with heavy alcohol use and typical liver tests without confounding factors
   • Possible AH: Clinically diagnosed but with potential confounding factors, uncertain alcohol history, or atypical labs 1

Indications for Liver Biopsy

Liver biopsy (preferably transjugular) is indicated in:

• Diagnostic uncertainty
• Patients being considered for specific treatment
• Cases of possible alcoholic hepatitis per NIAAA classification
• Atypical presentation or laboratory findings:
  • AST <50 IU/mL or >400 IU/mL
  • AST/ALT ratio <1.5 1, 2

Histological Features

When performed, liver biopsy typically shows:

• Macrovesicular steatosis
• Neutrophil infiltration
• Hepatocyte ballooning
• Mallory-Denk bodies
• Perisinusoidal fibrosis
• Cholestasis (bilirubinostasis)
• "Chicken-wire" pattern fibrosis 1

Disease Severity Assessment

After diagnosis, severity should be assessed using:

• Maddrey's Discriminant Function: ≥32 indicates severe alcoholic hepatitis
• MELD score: Threshold between 17-20 indicates severe disease 1, 2

Common Pitfalls and Caveats

1. Misdiagnosis risk: 10-20% of clinically diagnosed cases may have other liver diseases or may not have histologic alcoholic steatohepatitis 1

2. Underestimating non-severe forms: Even with Maddrey score <32, symptomatic alcoholic hepatitis carries approximately 20% 1-year mortality 1, 2

3. Overlooking underlying cirrhosis: 30-40% of alcoholic hepatitis cases may have underlying cirrhosis 1, 2

4. Relying solely on clinical diagnosis: In the absence of liver biopsy, more stringent clinical and laboratory criteria should be applied to avoid misdiagnosis 1

5. Incomplete alcohol history: Patients may not be forthcoming about their degree of alcohol consumption 3

The diagnosis of alcoholic hepatitis requires a systematic approach combining clinical, laboratory, and sometimes histological findings. While liver biopsy remains the gold standard for definitive diagnosis, a probable diagnosis can be made based on clinical criteria in patients with typical presentations.