What are the expected levels of Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), and Alkaline Phosphatase (ALK Phos) in a patient with cholecystitis?

Expected Liver Enzyme Levels in Cholecystitis

In acute cholecystitis without common bile duct stones, AST and ALT are typically elevated in 15-50% of patients, with mild to moderate elevations (usually less than 300 U/L), while ALP is elevated in 15-50% of patients but rarely exceeds 3x the upper limit of normal. 1

Characteristic Liver Enzyme Patterns in Cholecystitis

Acute Cholecystitis Without CBD Stones

• AST/ALT: Mild to moderate elevations in 15-50% of patients
  • Usually less than 300 U/L 2
  • Median values around 47 U/L for AST and 82.5 U/L for ALT 3
• ALP: Elevated in 15-50% of patients
  • Typically 1.69±0.118 fold increase above normal 4
• GGT: Often elevated
• Bilirubin: Elevated in 15-50% of patients
  • Median around 1.21 mg/dL 3

Acute Cholecystitis With CBD Stones

• AST/ALT: Elevated in approximately 90% of patients 1
  • Median values around 58 U/L for AST and 96 U/L for ALT 3
• ALP: Elevated in approximately 77% of patients 1
  • Typically 2.5±0.57 fold increase above normal 4
• Bilirubin: Elevated in approximately 60% of patients
  • Median around 1.53 mg/dL 3

Key Diagnostic Considerations

1. Enzyme pattern inconsistent with cholecystitis:

   • AST/ALT >300 U/L (unless there's concurrent CBD obstruction) 2, 5
   • ALP >3x normal without evidence of CBD stones 1, 4
   • Persistently elevated enzymes beyond the acute phase

2. Differentiating factors:

   • GGT is the most reliable test for detecting CBD stones in acute cholecystitis (sensitivity 80.6%, specificity 75.3% at a cut-off of 224 IU/L) 1
   • More than 2.5-fold rise in ALP strongly suggests CBD stones rather than simple cholecystitis 4
   • Total bilirubin level is an independent predictor of choledocholithiasis 3

3. Common pitfalls:

   • Relying solely on liver enzymes to diagnose CBD stones (not recommended by guidelines) 1
   • Attributing markedly elevated aminotransferases (>400 IU/L) to cholecystitis without considering "gallstone hepatitis" - a condition where sudden gallstone migration through a narrow CBD causes transient, severe enzyme elevation 5
   • Failing to recognize that fatty liver can influence liver enzyme patterns in cholecystitis patients 3

Clinical Implications

• Liver enzymes in cholecystitis typically show a cholestatic pattern (predominant ALP/GGT elevation) rather than a hepatocellular pattern (predominant AST/ALT elevation) 2
• Patients with markedly elevated aminotransferases without cholangitis ("gallstone hepatitis") tend to be younger and experience more severe, short-lasting abdominal pain 5
• Enzyme elevations alone are insufficient for diagnosing CBD stones - further imaging (MRCP, EUS, or ERCP) is required 1
• The World Society of Emergency Surgery recommends against using elevated LFTs or bilirubin as the only method to identify CBD stones in patients with acute cholecystitis 1

Remember that liver enzyme patterns should be interpreted in conjunction with clinical presentation, imaging findings, and other laboratory values for accurate diagnosis and management of cholecystitis.