What are the common causes of pancreatitis?

Common Causes of Pancreatitis

Gallstones and alcohol are the two dominant causes of acute pancreatitis, together accounting for 60-75% of all cases, with gallstones being the leading cause in most regions and alcohol being the second most common. 1, 2

Acute Pancreatitis: Primary Etiologies

Most Common Causes (75% of cases)

• Gallstones represent the leading cause, accounting for 60-75% of acute pancreatitis cases in many countries, occurring when biliary lithiasis causes pancreatic duct obstruction 1, 3
• Alcohol consumption is the second most common cause overall, with incidence varying by region and associated with high intake 1, 2

Metabolic Causes (5-10% of cases)

• Hypertriglyceridemia causes acute pancreatitis particularly when triglyceride levels exceed 700-1000 mg/dL, and patients with severe hypertriglyceridemia (≥1,000 mg/dL) have a 14% incidence of acute pancreatitis 4, 3, 5
• Hypercalcemia disrupts normal pancreatic secretion leading to chronic inflammation 6, 3
• Diabetic ketoacidosis complicated by hypertriglyceridemia can induce acute pancreatitis in previously undiagnosed diabetes patients 7

Drug-Induced Pancreatitis

• Azathioprine and 6-mercaptopurine cause pancreatitis in approximately 4% of treated IBD patients, typically occurring within the first 3-4 weeks of treatment in a dose-independent manner 4, 1
• 5-ASA medications have a much lower risk of inducing pancreatitis compared to thiopurines 4
• Various other medications can cause drug toxicity leading to pancreatitis 5, 8

Procedural and Traumatic Causes

• Post-ERCP pancreatitis is a recognized complication of endoscopic retrograde cholangiopancreatography 4, 5
• Abdominal trauma can precipitate acute pancreatitis 5, 8

Anatomical and Structural Causes

• Pancreatic duct abnormalities including obstruction, strictures, or anatomical variants like pancreas divisum predispose to pancreatitis 1, 6
• Duodenal Crohn's disease can cause pancreatitis through direct extension or fistulizing disease 4

Autoimmune and Infectious Causes

• Autoimmune pancreatitis, including IgG4-related pancreatitis, has been described in IBD patients 4, 1
• Various infections including mumps, Coxsackie B4, and others can trigger acute pancreatitis 4, 5

Idiopathic Pancreatitis (15-20% of cases)

• Approximately 15-20% of cases remain idiopathic despite thorough evaluation, though this percentage should be minimized through vigorous investigation 4, 3, 8
• Microlithiasis (microscopic gallstones) may be responsible for some previously labeled "idiopathic" cases and can be detected through bile sampling or endoscopic ultrasound 4, 3

Chronic Pancreatitis: Distinct Etiologic Pattern

Dominant Cause

• Alcohol is the etiological factor in 60-70% of chronic pancreatitis cases in Western countries, with risk increasing with higher intake 1, 6, 3

Tobacco as Independent Risk Factor

• Cigarette smoking is a significant independent risk factor accounting for 25-30% of cases and accelerates disease progression 6, 3
• Combined alcohol and tobacco use has synergistic effects on disease progression 3

Genetic Factors

• Hereditary pancreatitis involves mutations in PRSS1, SPINK1, and CFTR genes and carries a 50-70-fold increased risk of pancreatic cancer with a cumulative lifetime risk of 40% by age 75 6

Geographic Variations

• Tropical pancreatitis affects younger, undernourished patients in tropical/subtropical countries with early diabetes development, representing a different disease pattern than Western alcohol-induced chronic pancreatitis 6

Critical Clinical Pitfalls

The diagnosis of idiopathic pancreatitis should not be accepted without obtaining at least two good quality ultrasound examinations, as the most sensitive test for missed gallstones remains a repeat ultrasound. 4

• Patients with HLA-DQA102:01-HLA-DRB107:01 haplotype are more prone to develop thiopurine-induced pancreatitis 4
• Asymptomatic elevated lipase is found in 7% of IBD patients, making diagnosis challenging when differentiating pancreatitis pain from active IBD 4
• In severe hypertriglyceridemia (≥1,000 mg/dL), pharmacotherapy effectiveness is limited because these agents primarily reduce hepatic VLDL synthesis rather than clearing circulating chylomicrons 4