This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
Most attacks of acute pancreatitis are mild and settle within a few days, but about one in five becomes severe, with necrosis of the pancreas, infection or organ failure. The CT severity index (CTSI), described by Emil Balthazar in 1990, grades the severity on a contrast-enhanced CT scan by adding two parts.
Balthazar grade
| Grade | CT findings | Points |
|---|---|---|
| A | normal pancreas | 0 |
| B | focal or diffuse enlargement of the pancreas | 1 |
| C | pancreatic changes with inflammation of the surrounding fat | 2 |
| D | a single fluid collection | 3 |
| E | two or more collections, or gas in or near the pancreas | 4 |
Necrosis
| Part of the pancreas not enhancing | Points |
|---|---|
| none | 0 |
| 30% or less | 2 |
| 30 to 50% | 4 |
| more than 50% | 6 |
The index runs from 0 to 10.
Example
Inflammation of the pancreas and surrounding fat (grade C, 2 points) with necrosis of under a third of the gland (2 points) gives an index of 4: moderate pancreatitis.
Interpretation
| Index | Severity | Mortality in Balthazar’s series | Complications |
|---|---|---|---|
| 0 to 3 | mild | 3% | 8% |
| 4 to 6 | moderate | 6% | 35% |
| 7 to 10 | severe | 17% | 92% |
A modified CTSI (Mortele, 2004) simplifies the grade to 0, 2 or 4 points and adds 2 points for extrapancreatic complications such as pleural effusion or ascites.
When to scan
Necrosis is often not visible in the first 72 hours, so an early CT can underestimate severity. Guidelines advise a scan at admission only when the diagnosis is uncertain, and otherwise after 72 to 96 hours if the patient is not improving. Severity is defined mainly by organ failure (the revised Atlanta classification), which clinical scores such as BISAP, Ranson or APACHE II help predict.