What is involved in patient assessment and severity stratification in acute pancreatitis?

Patient Assessment and Severity Stratification in Acute Pancreatitis

The Bedside Index of Severity of Acute Pancreatitis (BISAP) score is the most accurate and applicable scoring system for everyday clinical practice due to its simplicity and ability to predict severity, death, and organ failure in acute pancreatitis. 1

Diagnostic Criteria

Acute pancreatitis diagnosis requires at least two of the following three criteria:

1. Characteristic abdominal pain (upper abdominal, often radiating to back)
2. Biochemical evidence: lipase or amylase >3× upper limit of normal
3. Characteristic imaging findings 2

Initial Laboratory Assessment

• Serum pancreatic enzymes:

  • Lipase is preferred (sensitivity 100%, specificity 99% when >3× upper limit) 2
  • Amylase rises within 6-24h, peaks at 48h, normalizes in 3-7 days 1

• Prognostic laboratory markers:

  • C-reactive protein ≥150 mg/L at 48-72 hours (indicates severe disease with ~80% accuracy) 1, 2
  • Hematocrit >44% (independent risk factor for pancreatic necrosis) 1
  • Blood urea nitrogen >20 mg/dL (independent predictor of mortality) 1
  • Procalcitonin (most sensitive for detecting pancreatic infection) 1

• Etiology workup:

  • Liver function tests (for biliary etiology)
  • Serum triglycerides (>1000 mg/dL indicates hypertriglyceridemia as cause) 1
  • Serum calcium levels 1

Imaging Studies

• Ultrasonography: First-line to identify gallstones but limited for pancreatic visualization 2

• Contrast-Enhanced CT (CECT):

  • Imaging modality of choice for diagnosis, staging, and detecting complications 1

  • Best performed 72-96 hours after symptom onset to assess necrosis

  • Allows calculation of CT Severity Index (CTSI):

    CT Severity Index	Morbidity	Mortality
    0-3	8%	3%
    4-6	35%	6%
    7-10	92%	17%

• MRI: Alternative when contrast CT is contraindicated; better for identifying non-liquefied material 1

• MRCP/EUS: For suspected biliary etiology when ultrasound is negative 1

Severity Assessment Scoring Systems

BISAP Score (Recommended for Clinical Practice)

Points assigned for each criterion present within 24 hours of admission:

• BUN >25 mg/dL
• Impaired mental status
• SIRS (≥2 criteria)
• Age >60 years
• Pleural effusion

A BISAP score ≥2 is a statistically significant cutoff for diagnosing severe acute pancreatitis, organ failure, and mortality 1

Other Scoring Systems

• APACHE-II: Most accurate but complex; score ≥8 indicates severe acute pancreatitis 1

  • Evaluates chronic health and 12 physiologic measurements
  • Can be performed at any time
  • Independent predictor for infected necrosis when elevated at 24h 1

• Ranson Criteria:

  • PPV: 28.6-49%
  • Sensitivity: 75-87%
  • Specificity: 68-77.5%
  • Can only be fully assessed after 48h 1

• Glasgow-Imrie Score:

  • PPV: 59-66%
  • Sensitivity: 61-71%
  • Specificity: 88-89%
  • Requires 48h for complete assessment 1

Limitations of Scoring Systems

1. Most scoring systems require >24h to stratify patients, potentially delaying critical interventions 1
2. Traditional focus on mortality may be outdated as overall mortality has declined 1, 3
3. No single scoring system covers the entire range of problems in acute pancreatitis 3
4. Early CT scanning has limited value as pancreatic necrosis may not fully develop within 48h 4

Recommended Assessment Algorithm

1. On admission:

   • Calculate BISAP score
   • Measure hematocrit (>44% indicates risk of necrosis)
   • Begin SOFA score monitoring (daily)
   • Order initial laboratory tests (lipase, amylase, CRP, BUN, creatinine)

2. At 48-72 hours:

   • Measure CRP (≥150 mg/L indicates severe disease)
   • Measure procalcitonin (for suspected infection)
   • Perform CECT if clinically indicated

3. Beyond first week:

   • Calculate CT Severity Index if CECT performed
   • Continue daily SOFA score monitoring for organ dysfunction

Clinical Implications

• 75% of patients requiring intensive care are transferred within the first 72h of admission 1
• Early identification of severe cases allows for:
  • Timely ICU admission
  • Appropriate fluid resuscitation
  • Anticipation of complications
  • Consideration of transfer to specialist centers 3

Common Pitfalls to Avoid

1. Relying on a single scoring system: Combine clinical assessment with multiple scoring tools 3
2. Delaying severity assessment: Early stratification is crucial for management decisions
3. Overuse of CT scans: Frequent repeat CTs increase radiation exposure with limited impact on decision-making 1
4. Overlooking clinical deterioration: Scores should complement, not replace, clinical judgment
5. Missing biliary etiology: Perform at least two ultrasound examinations in idiopathic cases 1