Diagnosis, severity stratification and management of adult acute pancreatitis–current evidence and controversies

Table 1 Summary of various scoring systems which has been developed and/or validated for use in acute pancreatitis

Name	Components	Interpretation	Advantages	Disadvantages
Ranson Score	Total of 11 variables to be used	Predicts severity of AP and mortality on admission and 48 h of admission	High prognostic accuracy (AUC 0.81) compared to APACHE II (AUC 0.80), BISAP (AUC 0.79) and CTSI (AUC 0.80) in prediction of AP severity[36]	Low sensitivity (66%) when used before 48 h compared to APACHE II (84%), Glasgow score (78%), HAPS (71%)
	On admission: (1) WBC > 16 × 109/L; (2) Age > 55 yr; (3) Glucose > 10 mmol/L (200 mg/dL); (4) AST > 250 IU/L; and (5) LDH > 350 IU/L	Severity of AP: < 3: Unlikely SAP; ≥ 3: Likely SAP	High prognostic accuracy (AUC 0.87) in prediction of mortality, similar to CTSI (AUC 0.87), slightly worse compared to APACHE II (AUC 0.91)[36]	Higher sensitivity than BISAP (54%)[38]
	48-h compared to admission: (1) Hct drop > 10%; (2) BUN increase > 1.79 mmol/L (5 mg/dL); (3) Calcium < 2 mmol/L (8 mg/dL); (4) Arterial PaO2 < 60 mmHg; (5) Base deficit > 4 mg/dL; and (6) Fluid needs > 6 L within 48 h	Mortality risk: 0-3: 1%; 3-4: 15%; 5-6: 40%; ≥ 7: Nearly 100%
The Glasgow-Imrie score	8 variables calculated at 48 h of admission: (1) PaO2 < 59.3 mmHg; (2) Age > 55 yr; (3) WBC > 15 × 109/L; (4) Calcium < 2 mmol/L (8 mg/dL); (5) BUN > 44.8 mg/dL (serum urea > 16 mmol/L); (6) LDH > 600 IU/L; (7) Albumin < 32 g/L (3.2 g/dL); and (8) Glucose > 10 mmol/L (180 mg/dL)	Predicts risk of SAP	Has decent sensitivity (78%) and specificity (82%) when used even within/before 48 h	Limited prognostic accuracy (< 70%) and positive predictive value (70%)
		Severity of AP: < 3: Unlikely SAP; ≥ 3: Likely SAP	High NPV in prediction for mortality (range 86%-100%)[39]	Unable to provide timely assessment as patients are scored only at 48 h (original design of scoring system)
		Risk of SAP in original study: 0: 7%; 1: 6%; 2: 16%; 3: 20%; 4: 61%; 5: 55%; 6: 100%; 7: 0%; 8: 100%		Low PPV for prediction of mortality (range 18%-66%)[39]
APACHE II	List of 15 variables used1: (1) History of severe organ failure/immunocompromised state e.g. Heart failure Class IV, cirrhosis, chronic lung disease, dialysis-dependent: (2) Age; (3) Temperature; (4) Mean arterial pressure; (5) Heart rate; (6) Respiratory rate; (7) FiO2; (8) Glasgow coma scale; (9) pH; (10) Sodium; (11) Potassium; (12) Creatinine; (13) Acute renal failure; (14) Hct; and (15) WBC count	Original use: Predicts mortality in ICU; Validated studies: Predicts severity and risk of mortality in AP	Can be used at any timepoint during the course of disease	Cumbersome to use in view of long list of variables required
		Interpretation2[32]: (1) < 8: Low risk of SAP, low risk of mortality; and (2) ≥ 8: High risk of SAP, high risk of mortality	Has decent sensitivity (71%) and specificity (80%) for predicting SAP, and has high sensitivity (92%) with slightly lower specificity (79%) in predicting mortality[36]	Low specificity compared to Ranson score at 48 h (62% vs 93%) at 48 h of admission[38]
CTSI	Consists of 2 components	Predicts severity of AP (Sum of Balthazar score and extent of pancreatic necrosis): 0-3: Mild AP; 4-6: Moderate AP; 7-10: SAP	Acceptable sensitivity (81%) and specificity (82%) in prediction of SAP[36]	While able to predict SAP, score did not correlate with subsequent development of organ failure and extra-pancreatic complications
	Balthazar score (grading of pancreatitis): A (0): Normal pancreas; B (1): Enlargement of pancreas; C (2): Inflammatory changes in pancreas and peripancreatic fat; D (3): Ill-defined single peripancreatic fluid collection; and E (4): ≥ 2 poorly defined peripancreatic fluid collection			Patients with > 30% necrosis have similar morbidity and mortality (additional scoring for > 50% is not useful)[29]
	Extent of pancreatic necrosis: None: 0; ≤ 30%: 2; > 30%-50%: 4; > 50%: 6			Requires the use of CT, and ideal time for imaging is ≥ 72 h from onset of symptoms
Modified CTSI (MCTSI)	Consists of 3 components:	Predicts severity of AP: 0-2: Mild AP; 4-6: Moderate AP; 8-10: SAP	Easier to calculate compared to CTSI	CT assessment of severity may not correlate with incidence of organ failure and risk of infection[30]
	Pancreatic inflammation: 0: Normal pancreas; 2: Intrinsic pancreatic abnormalities with/without inflammatory changes in peripancreatic fat; 4: Pancreatic/peripancreatic fluid collection/peripancreatic fat necrosis		Higher interobserver reliability compared to CTSI	Requires the use of CT, and ideal time for imaging is ≥ 72 h from onset of symptoms
	Pancreatic necrosis: 0: None; 2: ≤ 30%; 4: > 30%		Comparable to CTSI in prognostic accuracy for severity of AP; MCTSI (AUC 0.83, sensitivity 88%, specificity 80%); CTSI (AUC 0.80, sensitivity 81%, specificity 82%)[30]
	Extra-pancreatic complications: 2: ≥ 1 of pleural effusion, ascites, vascular complications, parenchymal complications and/or gastrointestinal involvement
BISAP	List of 5 variables used: (1) BUN > 25 mg/dL; (2) Impaired mental status; (3) SIRS; (4) Age > 60 yr; and (5) Pleural effusion	Predicts mortality in AP. Mortality risk in original study (within 24 h in patients without evidence of organ failure)[28]: 0: 0.1%; 1: 0.4%; 2: 1.6%; 3: 3.6%; 4: 7.4%; 5: 9.5%	Easy to use scoring system which can be used within 24 h of admission	Potential underscoring of patients if done within 24 h as pleural effusion may be a late development
		Varying cut-offs proposed for mortality[37]: ≥ 2: AUC 0.82, sensitivity 81%, specificity 70%; ≥ 3: AUC 0.87, sensitivity 56%, specificity 91%		Low sensitivity in prediction of SAP
		Varying cut-offs proposed for SAP risk: ≥ 2: AUC 0.88, sensitivity 63%, specificity 82%; ≥ 3: AUC 0.87, sensitivity 51%, specificity 91%		Inferior to Ranson score in prediction of mortality[37]
HAPS	List of 3 variables: (1) Absence of rebound tenderness/guarding; (2) Normal Hct (males: ≤ 43.0%, females ≤ 39.6%); and (3) Normal creatinine ≤ 176.8 μmol/L (2 mg/dL)	Predicts risk of mild AP	Easy and quick to use scoring system to predict risk of mild AP to determine disposition	May miss out cases which appear to be mild AP but progress to moderately severe or severe if patients present early
		Interpretation: 0: Predicts no pancreatic necrosis, need for dialysis, mechanical ventilation, or fatal outcome (PPV 98%, NPV 18%, specificity 97%, sensitivity 28%)[33]; ≥ 1: Unable to exclude risk of above		Unable to predict risk of SAP
SOFA	List of 5 variables used1, within 24 h of admission (graded 0-4 for each variable): (1) Glasgow coma scale; (2) Mean arterial pressure, or need for vasoactive agents; (3) PaO2/FiO2; (4) Platelet count; and (5) Total bilirubin	Original use: Predicts mortality in ICU	Relatively easy to use scoring system compared to APACHE II, Ranson score and Glasgow-Imrie score	Underperforms compared to Ranson score (NPV for SAP: 98.0%, NPV for ICU admission: 100%, NPV for mortality: 100%) and Glasgow-Imrie score (NPV for SAP: 95.4%, NPV for ICU admission: 99.3%, NPV for mortality: 99.5%) when scored at 48 h[35]
		Validated studies[35,42]: Predicts risk of SAP, ICU admission and mortality in AP	High NPV which can screen out mild disease or need for ICU admission at onset within 24 h of admission
		Cut-off score of ≥ 7 to predict SAP, ICU admission and mortality: (1) SAP: AUC 0.966, PPV: 84.6%, NPV: 89.1%, sensitivity: 13.6%, specificity: 99.7%; (2) ICU admission: AUC 0.943, PPV: 61.5%, NPV: 98.1%, sensitivity 40.0%, specificity: 99.2%; and (3) Mortality: AUC: 0.968, PPV: 46.2%, NPV: 99.1%, sensitivity: 50.0%, specificity: 98.9%

¹The APACHE II score and SOFA score are detailed scoring systems which take into account patients’ acute and chronic disease, signs, and laboratory values. Each variable consist of multiple components for which a score will be allocated for different range of values. The exact breakdown and scoring of each variable will not be included in this table due to its complexity.

²The original Atlanta classification in 1992 defined severe acute pancreatitis as APACHE II ≥ 8.

AP: Acute pancreatitis; APACHE: Acute Physiology and Chronic Health Evaluation; AST: Aspartate transaminase; AUC: Area under curve; BISAP: Bedside Index of Severity in Acute Pancreatitis; BUN: Blood urea nitrogen; CTSI: Computed tomography severity index; F_iO₂: Fraction of inspired oxygen; HAPS: Harmless Acute Pancreatitis Score; Hct: Hematocrit; ICU: Intensive care unit; LDH: Lactate dehydrogenase; MCTSI: Modified computed tomography severity index; NPV: Negative predictive value; P_aO2: Partial pressure of oxygen; PPV: Positive predictive value; SAP: Severe acute pancreatitis; SIRS: Systemic inflammatory response syndrome; SOFA: Sequential Organ Failure Assessment; U/L: Units per litre; WBC: White blood cell.