Severity Assessment and Imaging Guidelines for Acute Pancreatitis

Initial Clinical Assessment

• Clinical assessment alone misclassifies roughly 50 % of patients with acute pancreatitis, making it an unreliable sole tool for severity determination. 1
• The presence of any organ failure (pulmonary, circulatory, or renal) identified on clinical examination signals a severe attack of pancreatitis. 1
• Persistent organ failure lasting more than 48 hours mandates urgent transfer to an intensive‑care unit. 3
• Routine abdominal ultrasound at admission is recommended to identify a biliary cause and to aid planning of definitive therapy (e.g., cholecystectomy). 3

Multivariate Scoring Systems (48 h)

• Glasgow score – ≥ 3 positive criteria define severe disease, with an overall diagnostic accuracy of 70‑80 %. 1
• APACHE II – A score ≥ 9 identifies severe pancreatitis; a lower threshold of ≥ 6 yields ≈ 95 % sensitivity for capturing virtually all complications. 1
• In severe cases, serial APACHE II assessments should be used to monitor for recovery, progression, or the onset of sepsis. 1

C‑Reactive Protein (CRP)

• CRP > 210 mg/L within the first 4 days predicts severe pancreatitis (≈ 80 % accuracy). 1
• CRP > 120 mg/L at the end of the first week also indicates a severe disease course. 1
• Combining CRP levels with the Glasgow criteria further improves prognostic performance. 1

Determinant‑Based Classification (DBC)

• The latest DBC stratifies acute pancreatitis into four categories:
  
  • Mild – no organ failure and no (peri)pancreatic necrosis.
  • Moderate – transient organ failure and/or sterile (peri)pancreatic necrosis.
  • Severe – persistent organ failure or infected (peri)pancreatic necrosis.
  • Critical – persistent organ failure and infected necrosis, with mortality up to 32 %. 3

Contrast‑Enhanced Computed Tomography (CT)

Indications & Timing

• Routine contrast CT is not required for the majority of acute pancreatitis patients. 3
• All patients classified as having severe pancreatitis should undergo contrast‑enhanced CT. 3
• The optimal window for CT acquisition is 72–96 hours after symptom onset; earlier scans miss necrotic/ischemic areas and rarely alter early management. 3
• CT is also indicated when the diagnosis remains uncertain. 3

Balthazar CT Severity Index

• The index combines a CT grade (0‑4 points) with the extent of necrosis (0‑6 points). 7

Recommended CT Protocol (per Balthazar)

• Use a spiral or multislice scanner.
• Administer 500 mL of oral contrast (via mouth or nasogastric tube).
• Acquire an initial non‑contrast series to delineate pancreatic parenchyma.
• Follow with a post‑contrast series after a 100 mL non‑ionic IV bolus at 3 mL/s.
• Images should have thin collimation (≤ 5 mm) and be obtained ≈ 40 seconds after contrast injection.
• Non‑opacification of ≥ 1/3 of the pancreas or a non‑enhancing area > 3 cm defines necrosis. 7

Follow‑up CT Recommendations

• Patients with a Balthazar index 0‑2 need repeat CT only if there is a new clinical change.
• Patients with an index 3‑10 should have repeat imaging only for clinical deterioration or lack of improvement.
• A single follow‑up CT before discharge may be considered in apparently uncomplicated recoveries to detect silent complications (e.g., pseudocyst, pseudo‑aneurysm). 7