Fact-sheet: Acute pancreatitis
Updated on 04/23/2019 at 9:46 AM
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Definition
- Under physiologic conditions, pancreatic juice enzymes are inactive within the acinar cell = PROENZYMES
- They are activated within the intestinal lumen when trypsinogen is converted to trypsin by enterokinase
- In Acute pancreatitis: there is premature intra-acinar or intraductal activation of trypsinogen (by cathepsin B?)
→ Autodigestion of pancreatic cells and peripancreatic fat by its own proteolytic enzymes (trypsin+++), which are released in an uncontrolled manner.
The diagnosis is established by the combination of:
1 - typical abdominal pain
2 - lipase > 3N
Clinical features
In severe acute pancreatitis, clinical examination shows a discrepancy between the severity of systemic signs and the paucity of findings on physical examination:
sudden, intense, and constant epigastric pain, transfixiant, with an antalgic knee-chest position;
vomiting;
paralytic ileus;
hypovolemic shock;
oligoanuria;
neuropsychiatric disturbances;
respiratory distress.
Laboratory findings
Hyperlipasemia (>3N);
positive urinary trypsinogen-2 dipstick test
Radiography
Abdominal radiograph (rarely performed as it is not indicated):
"sentinel loop" of jejunum in the left hypochondrium;
diffuse ileus;
radiopaque calcifications localized to the pancreatic area.
Allows exclusion of pneumoperitoneum from hollow viscus perforation.
Ultrasound
Technically difficult during an episode of acute pancreatitis due to reflex ileus. A normal ultrasound does not exclude a biliary etiology of acute pancreatitis.
--> To be performed within 48 hours to exclude/confirm a lithiasic origin!
Findings suggestive of acute pancreatitis:
enlarged pancreas;
peripancreatic fluid collections.
Findings suggestive of a lithiasic origin:
gallbladder lithiasis;
rarely, cholelithiasis.
CT
It is performed at admission only in cases of diagnostic uncertainty and should be repeated at 72–96 hours to assess the severity of pancreatitis (mCTSI).
Performed without and with contrast injection.
4 distinct types of collections have been defined since the 2012 revision of the 1989 Atlanta consensus classification:
- In interstitial edematous acute pancreatitis: APFC < 4 weeks: Acute Peripancreatic Fluid Collection
- free and homogeneous fluid
- WITHOUT a wall
- Adjacent to and near the pancreas
- bounded by fascial planes
- low density (< 15 HU)
- most often resolves spontaneously
- Pseudocysts > 4 weeks: fluid collection
- HOMOGENEOUS
- round or oval
- low density (10-20 HU)
- well-defined, thin enhancing wall
- +/- gas if the pseudocyst is infected
- In necrotizing pancreatitis (lack of intraparenchymal enhancement): ANC: Acute Necrotic Collection < 4 weeks, HETEROGENEOUS collection (fluid and solid)
- high density > 15 HU
- no wall, poorly defined
- Adjacent to and/or distant from the pancreas
- +/- gas if infected
- WON: Walled-Off Necrosis > 4 weeks, HETEROGENEOUS collection
- thick, well-defined wall
-Demonstrates complications:
- vascular: ARTERIAL
- pseudoaneurysm
- arterial erosion
- VENOUS thrombosis
- segmental portal hypertension
- digestive: pancreatic ascites
- jaundice
- fistulization / digestive tract compression
- reflex ileus.
Vascular intervention
urgently in case of pseudoaneurysm of the:
- splenic artery ++
- gastroduodenal arteries
- pancreaticoduodenal arcades
Management
-Gastric suction (in case of repeated vomiting)
-Fluid, electrolyte, and energy replacement
-Analgesic treatment
-Oxygen therapy and ventilatory support in case of respiratory distress
-Antibiotic therapy guided by antibiogram after possible sampling of the necrosis in case of local or systemic infection.
Treatment of an identified cause: alcohol cessation, cholecystectomy or endoscopic sphincterotomy, treatment of hypertriglyceridemia...
Surgical indications are aimed at evacuating and draining infected necrosis.
Classification
CT severity index (Balthazar CTSI) maximum total of 10 points.
Pancreatic and peripancreatic inflammation
-Grade A: normal pancreas (0 points)
-Grade B: focal or diffuse enlargement of the pancreatic gland (1 point)
-Grade C: heterogeneous pancreas and peripancreatic fat stranding (2 points)
-Grade D: a single peripancreatic collection (3 points)
-Grade E: two or more peripancreatic collections or presence of gas bubbles within a collection (4 points)
Pancreatic necrosis:
-no necrosis (0 points)
-necrosis <30% (2 points)
-necrosis between 30 and 50% (4 points)
-necrosis >50% (6 points)
Prognostic value:
-CTSI <= 3: morbidity 8%, mortality 3%.
-CTSI 4-6: morbidity 35%, mortality 6%.
-CTSI >= 7: morbidity 92%, mortality 17%.
--- CTSI becomes mCTSI (Mortele score) ---
A. Pancreatic inflammation
- Normal pancreas = 0 pt
- Pancreatic abnormality with or without peripancreatic fat inflammation = 2 pts
- Pancreatic or peripancreatic fluid collection or peripancreatic fat necrotic collection = 4 pts
B. Pancreatic necrosis
- None = 0 pts
- < 30% = 2 pts
- >30% = points
C. Extrapancreatic complication = 2 pts
- Pleural effusion
- Ascites
- Vascular complication (venous thrombosis, pseudoaneurysm, or arterial hemorrhage)
- GI tract involvement
==> Total:
- 0 - 3: mild AP
- 4 - 6: moderate AP
- 7 - 10: severe AP
Limited value of the classifications in therapeutic management.
CTSI remains more relevant than mCTSI in practice
