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Pancreatitis Severity Scoring Systems
Predicting the severity of acute pancreatitis (AP) at presentation guides triage (ward vs. step-down vs. ICU), fluid resuscitation strategy, nutritional planning, and timing of interventions. Multiple scoring systems exist; none is definitively superior to the others, and most have high false-positive rates.
1. Revised Atlanta Classification (2012)
The current standard framework - not a numeric score but a clinical classification:
| Severity | Criteria |
|---|
| Mild | No organ failure, no local/systemic complications |
| Moderately Severe | Transient organ failure (<48 h) OR local/systemic complications |
| Severe | Persistent organ failure (>48 h) |
Organ failure is defined by a Modified Marshall score ≥2 in any of:
- Respiratory: PaO2 <60 mmHg
- Cardiovascular: Systolic BP <90 mmHg or HR >130 bpm
- Renal: Serum creatinine >2.0 mg/dL
Limitation: Patients cannot be classified as severe until 48 hours after presentation - limits ED utility.
- Rosen's Emergency Medicine, p. 1268
2. Ranson's Criteria (1974)
The oldest and most recognized score. Uses 11 parameters - 5 at admission and 6 at 48 hours.
Nongallstone Pancreatitis
| At Admission | At 48 Hours |
|---|
| Age >55 years | Hematocrit fall >10% |
| WBC >16,000/mm³ | BUN rise >5 mg/dL |
| Blood glucose >200 mg/dL | Serum calcium <8 mg/dL |
| Serum LDH >350 IU/L | PaO2 <60 mmHg |
| Serum AST >250 IU/L | Base deficit >4 mEq/L |
| Fluid sequestration >6 L |
Gallstone Pancreatitis
| At Admission | At 48 Hours |
|---|
| Age >70 years | Hematocrit fall >10% |
| WBC >18,000/mm³ | BUN rise >2 mg/dL |
| Blood glucose >220 mg/dL | Serum calcium <8 mg/dL |
| Serum LDH >400 IU/L | Base deficit >5 mEq/L |
| Serum AST >250 IU/L | Fluid sequestration >4 L |
Interpretation:
- <3 criteria - Mild, uncomplicated disease
- ≥3 criteria - Severe pancreatitis (defines severe AP)
- >6 criteria - ~50% mortality risk
Performance: PPV ~50%, NPV ~90% - mainly used to rule out severe disease, not rule it in.
- Schwartz's Principles of Surgery, p. 1472; Sabiston Textbook of Surgery, p. 2000
3. BISAP Score (2008)
Bedside Index of Severity in Acute Pancreatitis - the most practical ED tool. Calculated within the first 24 hours.
| Variable | Criterion | Points |
|---|
| B - BUN | >25 mg/dL | 1 |
| I - Impaired mental status | GCS <15 | 1 |
| S - SIRS | ≥2 of 4 SIRS criteria present | 1 |
| A - Age | >60 years | 1 |
| P - Pleural effusion | Present on imaging | 1 |
Interpretation:
- Score 0-1: <1% mortality
- Score ≥3: Substantially increased in-hospital mortality, high risk for organ failure and pancreatic necrosis
- Score 5: >20% mortality
Advantage: Simple, calculable at ED presentation, correlates well with organ failure and necrosis risk.
- Harrison's Principles of Internal Medicine 22E, p. 681; Sabiston Textbook of Surgery
4. APACHE II Score
Originally designed for ICU use. Consists of 12 physiologic variables + age points + chronic health points. Not calculated quickly at bedside.
-
APACHE II ≥8 = severe acute pancreatitis (high risk)
-
The score can be recalculated daily to track disease progression
-
More useful for ongoing ICU monitoring than initial ED triage
-
Rosen's Emergency Medicine, p. 1268; Sabiston Textbook of Surgery
5. CT Severity Index (CTSI) - Balthazar Score
Imaging-based scoring using contrast-enhanced CT (ideally portal venous phase, 65-70 sec post-contrast).
Scoring (Total max = 10 points)
Pancreatic Inflammation (0-4 points):
| CT Finding | Points |
|---|
| Normal pancreas | 0 |
| Focal/diffuse enlargement only | 1 |
| Peripancreatic fat inflammatory changes | 2 |
| Single fluid collection or phlegmon | 3 |
| Two or more fluid collections or gas in/adjacent to pancreas | 4 |
Pancreatic Necrosis (0-6 points):
| Necrosis | Points |
|---|
| None | 0 |
| ≤30% | 2 |
| 30-50% | 4 |
| >50% | 6 |
Outcome by CTSI:
| Score | Mortality | Morbidity |
|---|
| 0-3 | 3% | 8% |
| 4-6 | 6% | 35% |
| 7-10 | 17% | 92% |
- CTSI ≥4 = high risk for severe disease
- Sabiston Textbook of Surgery, p. 2001
CT example of Balthazar Grade E pancreatitis:
6. Modified Glasgow (Imrie) Criteria
An 8-parameter score calculated at 48 hours. Used widely in the UK.
| Parameter | Threshold |
|---|
| Age | >55 years |
| WBC | >15,000/mm³ |
| Blood glucose | >180 mg/dL (no diabetic history) |
| Serum urea | >45 mg/dL |
| PaO2 | <60 mmHg |
| Serum calcium | <8 mg/dL |
| Serum albumin | <3.2 g/dL |
| Serum LDH | >600 IU/L |
Score ≥3 at 48 hours = severe pancreatitis.
7. SIRS Criteria - Simplest Predictor
Persistent SIRS (present at admission AND at 48 hours) is as predictive of severity as the complex scores, and simpler to apply.
| SIRS status | Mortality |
|---|
| Never meets SIRS criteria | ~0% |
| Transient SIRS (resolves before 48 h) | ~8% |
| Persistent SIRS (>48 h) | ~25% |
SIRS requires ≥2 of: Temp >38°C or <36°C; HR >90; RR >20 or PaCO2 <32; WBC >12,000 or <4,000 or >10% bands.
- Sabiston Textbook of Surgery
8. Biochemical Markers
| Marker | Threshold | Notes |
|---|
| CRP | >150 mg/L | Peaks at 48-72 h; not useful at admission |
| BUN (admission) | Elevated | Rising BUN during hospitalization = higher mortality |
| Hematocrit | Elevated (>44%) | Hemoconcentration = dehydration and necrosis risk |
| Procalcitonin | Elevated | Correlates with severity; not widely standardized |
Summary - Severity Cutoffs for "Severe" AP
| Scoring System | Cutoff for Severe |
|---|
| Atlanta 2012 | Persistent organ failure >48 h |
| Ranson | ≥3 criteria |
| BISAP | ≥3 points |
| APACHE II | ≥8 |
| CTSI | ≥4 |
| Glasgow/Imrie | ≥3 at 48 h |
| SIRS | Persistent at 48 h |
Clinical Triage Guidance (Harrison's 22E)
- BISAP 0-1 + low BUN/hematocrit, good response to fluids - regular ward
- Persistent SIRS at 24 h or comorbidities - step-down unit
- High BISAP + high BUN/hematocrit + no response to fluids + organ failure - direct ICU admission
Harrison's Principles of Internal Medicine 22E; Rosen's Emergency Medicine; Sabiston Textbook of Surgery
