Gallstones as a Cause of Pancreatitis

Gallstones are the leading cause of acute pancreatitis, accounting for 60-75% of all cases. 1

Mechanism and Epidemiology

Gallstone pancreatitis occurs when a gallstone migrates and causes transient obstruction of the ampulla of Vater, leading to intraglandular activation of pancreatic enzymes 2
Gallstones are found in 7-20% of patients undergoing cholecystectomy, making them the most common single cause of acute pancreatitis in Western countries 3, 4
Risk factors for gallstone pancreatitis include increased number and smaller size of stones 5

Diagnosis is based on at least two of three criteria: upper abdominal pain, elevated serum lipase/amylase, and consistent abdominal imaging 6
Initial investigations should include:
- Pancreatic enzymes in plasma (elevation above 1000 IU/L is suggestive) 2
- Liver function tests (elevated LFTs often indicate biliary etiology) 7
- Ultrasound of gallbladder (first-line imaging to identify gallstones) 6, 7
Patients with gallstone pancreatitis typically present with both features of acute pancreatitis and a cholestatic clinical picture 5

Supportive care with fluid therapy and enteral nutrition 5
Schedule laparoscopic cholecystectomy with operative cholangiography within 2 weeks after discharge, preferably during the same hospital admission 8, 7
Delaying cholecystectomy beyond two weeks increases risk of potentially fatal recurrent acute pancreatitis 8, 7

Admit to high dependency unit or intensive care unit with full monitoring and systems support 8, 6
Urgent therapeutic ERCP with sphincterotomy should be performed within 72 hours of symptom onset, especially when there is:
- Cholangitis
- Jaundice
- Dilated common bile duct
- Failure to improve within 48 hours despite intensive resuscitation 8, 6
Delay cholecystectomy until signs of lung injury and systemic disturbance have resolved 8, 6
CT scanning should be obtained within 3-10 days to assess for complications such as necrosis or fluid collections 7, 4

For patients unfit for surgery, endoscopic sphincterotomy alone is adequate treatment to prevent recurrence 8
Patients with infected pancreatic necrosis require intervention to completely debride all cavities containing necrotic material 8
All patients with gallstones and acute pancreatitis require imaging of the bile duct 8

Failing to perform ERCP in patients with cholangitis or biliary obstruction can lead to increased morbidity and mortality 7
Delaying definitive treatment (cholecystectomy) increases risk of recurrent attacks 8, 4
Patients with severe disease require close clinical monitoring and a multidisciplinary approach between surgeon, radiologist, gastroenterologist, and intensivist 4
In patients with inflammatory bowel disease, abdominal pain due to pancreatitis can be difficult to differentiate from that caused by active IBD 6