BISAP Score in Acute Pancreatitis Management
The BISAP score is one of the most accurate and practical tools for early risk stratification in acute pancreatitis, particularly valuable because it can be calculated within the first 24 hours of admission to identify patients at increased risk of mortality, severe disease, and organ failure before complications develop. 1, 2
What is BISAP?
The BISAP (Bedside Index for Severity in Acute Pancreatitis) is a simplified prognostic scoring system that evaluates five parameters within 24 hours of admission: 1, 2
- Blood urea nitrogen >25 mg/dL (>8.9 mmol/L)
- Impaired mental status
- Systemic inflammatory response syndrome (SIRS) present
- Age >60 years
- Pleural effusion on radiography
Each criterion scores one point, for a maximum score of 5. 1
Critical Cutoff Values
A BISAP score ≥2 is the statistically significant cutoff for predicting severe acute pancreatitis, organ failure, and mortality. 1, 3
- BISAP ≥3 indicates high specificity (91%) for mortality and severe disease, though with moderate sensitivity (51-56%). 4, 5
- The score demonstrates an area under the curve (AUC) of 0.80 for predicting severe pancreatitis and 0.93 for organ failure. 2
Key Advantages Over Traditional Scoring Systems
BISAP's primary advantage is its ability to identify high-risk patients within 24 hours, unlike Ranson criteria or Glasgow score which require 48 hours to complete. 1
- BISAP has similar accuracy to APACHE-II (AUC 0.80-0.81 vs 0.78-0.80 for severe pancreatitis) but is far simpler to calculate at the bedside. 5, 3
- Most importantly, BISAP can identify patients at increased risk of mortality BEFORE the onset of organ failure, enabling earlier intervention. 1
- Compared to Ranson criteria (PPV 28.6-49%) and Glasgow score (PPV 59-66%), BISAP demonstrates superior specificity (91%) though lower sensitivity. 1, 4
Clinical Application in Alcohol-Related Pancreatitis
For a patient with acute pancreatitis and alcohol abuse history, calculate BISAP immediately upon admission: 2, 6
- Consider ICU-level monitoring or transfer
- Initiate aggressive fluid resuscitation
- Monitor closely for organ failure development
- Obtain baseline procalcitonin for infection risk assessment 1, 6
- Plan contrast-enhanced CT between days 3-10 to assess necrosis 2, 6
If BISAP <2: 3
- Standard ward-level care is typically appropriate
- Continue routine monitoring
- Reassess if clinical deterioration occurs
Important Caveats and Pitfalls
Do NOT use BISAP score as justification for prophylactic antibiotics - even in patients with high BISAP scores, prophylactic antibiotics are not recommended as they do not reduce mortality or morbidity in sterile pancreatitis. 1
Do NOT wait for complete scoring before initiating aggressive management - begin fluid resuscitation and supportive care immediately based on clinical presentation, using BISAP for risk stratification rather than treatment delay. 6, 7
Consider obesity as an additional risk factor - some evidence suggests adding BMI >25 to BISAP (creating "BISAP-O") may improve sensitivity for severe disease, though this requires further validation. 8
Complementary Assessment Tools
While BISAP is excellent for early assessment, combine it with: 2, 6
- C-reactive protein on day 3 (≥150 mg/L indicates severe disease with 80% accuracy) 1, 6
- Daily APACHE-II scores for ongoing monitoring of disease progression 2, 7
- CT Severity Index (CTSI) between days 3-10 in patients with predicted severe disease (CTSI ≥3 indicates severe disease) 2, 6
- Procalcitonin for detecting infected necrosis (highly sensitive negative predictor) 1, 9
Performance Characteristics Summary
BISAP demonstrates: 4, 5, 9, 3
- Sensitivity: 51-75% for severe disease, 56% for mortality
- Specificity: 91% for both severe disease and mortality
- Positive likelihood ratio: 5.65-7.23
- Negative likelihood ratio: 0.48-0.56
- AUC for organ failure: 0.93 (excellent discrimination)
The high specificity means BISAP is particularly useful for ruling IN severe disease when positive, while the moderate sensitivity means a low score does not completely exclude risk and requires continued clinical vigilance. 4, 3