1BISAP Score — Pancreatitis Severity Guide
The BISAP (Bedside Index of Severity in Acute Pancreatitis) score was developed by Wu et al. (2008) from a prospective study of 17,992 hospitalised pancreatitis patients in the United States. It was designed as a simple five-point bedside score calculable within 24 hours of admission — without requiring CT imaging or complex scoring algorithms — to predict in-hospital mortality from acute pancreatitis. It outperforms the Ranson score in terms of bedside applicability while achieving comparable discriminative accuracy.
| BISAP Score | In-Hospital Mortality | Organ Failure Risk | Severity Class |
|---|---|---|---|
| 0 | <1% | <2% | Mild |
| 1 | ~1% | ~5% | Mild |
| 2 | ~3% | ~10% | Moderate |
| 3 | ~10% | ~25% | Severe |
| 4 | ~20–30% | ~40% | Severe |
| 5 | ~50% | ~50%+ | Critical |
Revised Atlanta Classification (2012) — Severity Categories
- Mild AP: No organ failure, no local or systemic complications. Usually self-limited. 30% of cases. Mortality <1%. Treatment: supportive — aggressive early IV fluid resuscitation, analgesia, early oral feeding when tolerated
- Moderately Severe AP: Transient organ failure (<48h) and/or local complications (acute peripancreatic fluid collection, pancreatic necrosis) without persistent organ failure. HDU/step-down care. Mortality 8%
- Severe AP: Persistent organ failure (>48h) in one or more organ systems (respiratory, renal, cardiovascular). ICU admission required. Mortality 30–50%
Fluid Resuscitation in Acute Pancreatitis
Early aggressive IV fluid resuscitation within the first 24 hours is the cornerstone of AP management. The ACG 2013 and AGA 2024 guidelines recommend:
- Fluid choice: Lactated Ringer's solution (LR) preferred over normal saline — reduces SIRS incidence and improves outcomes (WATERFALL trial 2022, Chen et al.)
- Rate: 250–500 mL/hr for first 12–24 hours in non-cardiac patients. Goal-directed resuscitation targeting: urine output >0.5 mL/kg/hr, HR <100, MAP >65 mmHg, haematocrit 35–44%
- Reassess at 6 and 24 hours: Decrease rate if haematocrit falling, BUN falling, adequate urine output. Avoid over-resuscitation — associated with abdominal compartment syndrome
- Nutritional support: Oral or enteral nutrition as early as tolerated. Early enteral feeding (within 24 hours) via nasogastric or nasojejunal route preferred in severe AP — reduces infections and mortality vs parenteral nutrition
Common Causes of Acute Pancreatitis — Memory Aid "I GET SMASHED"
- Idiopathic (15–25%)
- Gallstones (40–50% — most common in South Asia and women)
- Ethanol/alcohol (30% — most common in Western countries)
- Trauma (blunt abdominal injury)
- Steroids, Mumps/infection, Autoimmune (IgG4 pancreatitis)
- Scorpion sting (relevant in India — Mesobuthus tamulus), Hypertriglyceridaemia (>1000 mg/dL), ERCP (post-ERCP pancreatitis ~3%), Drugs (azathioprine, didanosine, valproate)
2Frequently asked questions
What does BISAP stand for?
BISAP: BUN >25 mg/dL, Impaired mental status (GCS <15), SIRS criteria present (≥2 of: temp <36 or >38°C, HR >90, RR >20 or PaCO2 <32, WBC <4000 or >12000), Age >60 years, Pleural effusion on imaging. Each criterion = 1 point, total 0–5, calculated in first 24 hours.
What BISAP score indicates severe pancreatitis?
Score 0: <1% mortality. Score 1: ~1-2%. Score 2: ~3-5%. Score 3: ~5-10%. Score 4: ~15-20%. Score 5: >20%. BISAP ≥3 indicates severe acute pancreatitis requiring ICU-level monitoring, aggressive IV fluid resuscitation, and specialist input.
How is acute pancreatitis managed?
Early aggressive IV fluid resuscitation (Lactated Ringer's preferred — reduces SIRS vs normal saline), adequate analgesia (IV morphine or tramadol), NPO initially then early enteral nutrition via NGT at 24-48 hours (reduces infected necrosis), monitoring for organ dysfunction. Antibiotics only if infected necrosis confirmed.
When is CT scan needed in pancreatitis?
CT abdomen with contrast (CECT) is indicated if: diagnosis is uncertain, or at 72-96 hours if patient is not improving — to assess necrosis extent (Balthazar grade/CT Severity Index). CT is not routinely needed in mild pancreatitis with clear clinical improvement. MRCP is preferred for biliary anatomy assessment.
What is the difference between BISAP and Ranson criteria?
Ranson criteria uses 11 parameters — 5 at admission and 6 at 48 hours — requiring a full 2-day wait before complete calculation. BISAP uses 5 parameters all available within 24 hours. Both have similar predictive accuracy (AUC ~0.82). BISAP is preferred for early risk stratification.
When is ERCP indicated in acute pancreatitis?
ERCP is indicated only when: cholangitis is present (urgent within 24 hours), or persistent biliary obstruction without cholangitis (within 72 hours). ERCP is NOT indicated in mild gallstone pancreatitis without biliary obstruction. Early cholecystectomy (same admission in mild cases) prevents recurrence and replaces prophylactic ERCP.
Medical disclaimer: This calculator is for educational and clinical decision-support purposes only. It does not replace clinical judgment or specialist consultation. RxMedCalc is not liable for clinical decisions made solely on this tool.