Causes of Pancreatitis

Primary Causes

• Gallstones are the leading cause of acute pancreatitis, accounting for 45-60% of cases, followed by alcohol abuse at 20-25%, with the remaining cases due to hypertriglyceridemia, medications, anatomical abnormalities, autoimmune processes, hypercalcemia, infections, trauma, and idiopathic causes 1, 2
• The American Gastroenterological Association recommends that gallstone migration obstructs the pancreatic duct, triggering inflammation and enzyme activation 1
• The risk of gallstones is increased in Crohn's disease but not ulcerative colitis, according to the Journal of Crohn's and Colitis 3
• Initial ultrasound may miss gallstones; at least two good-quality ultrasound examinations should be performed before labeling a case as idiopathic, as suggested by the Praxis Medical Insights 1, 2
• MRCP has 97.98% sensitivity and 84.4% specificity for choledocholithiasis when ultrasound is negative but clinical suspicion remains high, according to the Praxis Medical Insights 2

Secondary Causes

• Alcohol is the second most common cause overall and the dominant etiological factor in chronic pancreatitis, accounting for 20-25% of acute cases and 60-70% of chronic cases, as stated by the Praxis Medical Insights 1, 2
• Excess alcohol consumption is the most common cause of chronic pancreatitis in Europe, according to the Annals of Oncology 4
• Hypertriglyceridemia is the third most common cause and carries a worse prognosis than other etiologies, as reported by the Praxis Medical Insights 5
• Serum triglyceride levels over 11.3 mmol/L indicate hypertriglyceridemia as the etiology, according to the Praxis Medical Insights 2
• Free fatty acids released by pancreatic lipase sequester calcium intravascularly, contributing to cellular injury and systemic hypocalcemia, as explained by the Praxis Medical Insights 2
• Azathioprine/6-mercaptopurine causes pancreatitis in approximately 4% of treated IBD patients, typically within the first 3-4 weeks of treatment, and is dose-independent, as stated by the Journal of Crohn's and Colitis 3, 5
• Patients carrying the HLA-DQA102:01-HLA-DRB107:01 haplotype are more prone to thiopurine-induced pancreatitis, according to the Journal of Crohn's and Colitis 3
• 5-ASA (mesalazine) has a much lower risk than thiopurines but can still cause pancreatitis, as reported by the Journal of Crohn's and Colitis and the Praxis Medical Insights 3, 5
• Elevated calcium activates pancreatic enzymes prematurely, leading to autodigestion and inflammation, as explained by the Praxis Medical Insights 1
• Fasting calcium concentrations must be determined in all patients with acute pancreatitis, especially when gallstones and alcohol have been excluded, as suggested by the Praxis Medical Insights 2
• Pancreas divisum and other pancreatic duct abnormalities obstruct normal pancreatic drainage, according to the Praxis Medical Insights 1
• Pancreatic duct changes (main duct obstruction, severe irregularity, dilatation) are found in 8% of Crohn's disease and 16% of ulcerative colitis patients, as reported by the Journal of Crohn's and Colitis 3
• Autoimmune pancreatitis has been described in IBD patients, according to the Journal of Crohn's and Colitis 3
• Post-ERCP pancreatitis is a recognized complication, as stated by the Journal of Crohn's and Colitis 3
• Trauma or surgery, particularly after abdominal or cardiac procedures, can cause direct pancreatic injury, according to the Praxis Medical Insights 1
• Post-operative acute pancreatitis represents a high-risk subset with worse outcomes, as reported by the Praxis Medical Insights 1
• Viral infections can occasionally trigger pancreatitis, according to the Praxis Medical Insights 1
• Helicobacter pylori infection increases relative risk (RR 1.5, attributable fraction 4-25%), as stated by the Annals of Oncology 4
• Germline mutations in BRCA2, p16, ATM, STK11, PRSS1/PRSS2, SPINK1, PALB2, and DNA mismatch repair genes increase pancreatic disease risk, according to the Annals of Oncology 4

Critical Clinical Pearls

• No more than 20-25% of cases should be labeled as idiopathic; approximately 10-25% remain unexplained after thorough workup, as suggested by the Praxis Medical Insights 1
• Endoscopic ultrasound may detect microlithiasis in the gallbladder or common bile duct in recurrent cases with no identified cause, according to the Praxis Medical Insights 2
• Two IBD-specific forms exist: one related to shared pathogenic pathways (autoimmune, idiopathic, granulomatous, PSC-associated) and one due to IBD management or associated diseases (biliary, drug-induced, duodenal Crohn's disease, post-procedural), as reported by the Journal of Crohn's and Colitis 3
• In IBD patients, the most common causes by decreasing frequency are drugs (mostly thiopurines), gallstones, alcohol, and ERCP, according to the Journal of Crohn's and Colitis 3