BISAP Score

Why use it

Simple, rapid prognostication in acute pancreatitis. Can be calculated within 24 hours of admission (unlike Ranson which requires 48h). Identifies patients who need ICU-level care and aggressive resuscitation.

About

The BISAP (Bedside Index for Severity in Acute Pancreatitis) score predicts mortality in acute pancreatitis using data available within the first 24 hours of admission. It uses five simple criteria: BUN > 25, Impaired mental status, SIRS, Age > 60, and Pleural effusion. It is simpler than Ranson and APACHE II while maintaining comparable accuracy.

When to use

• All patients admitted with acute pancreatitis
• Within the first 24 hours of hospital admission
• Triage: floor vs. ICU disposition

Formula

Pearls & pitfalls

• BISAP is calculated within 24 hours — faster than Ranson (48h) and simpler than APACHE II.
• BISAP ≥ 3 is associated with up to 10× increased mortality risk.
• SIRS criteria within BISAP: ≥ 2 of temp > 38°C or < 36°C, HR > 90, RR > 20, WBC > 12K or < 4K.
• Pleural effusion on admission imaging (CXR or CT) scores +1.
• Does not predict necrotizing pancreatitis directly — use CT severity index (Balthazar) for that.
• Early aggressive IV fluid resuscitation (goal-directed) is critical regardless of score.

Next steps

Score 0: Very low mortality risk (~0.1%). Score 1-2: Low risk — floor admission, monitor. Score 3-5: High risk (~5-22% mortality) — ICU consideration, aggressive fluid resuscitation, close monitoring for organ failure.

Evidence

Derived by Wu et al. (Gut, 2008) from > 17,000 patients. Validated in multiple cohorts. BISAP ≥ 3 associated with 7-12× increase in organ failure and 10× increase in mortality compared to BISAP < 3.

References

1. Wu BU et al. The early prediction of mortality in acute pancreatitis: a large population-based study. Gut. 2008;57(12):1698-1703. — link