Alcohol-induced and hereditary chronic pancreatitis are the two most common etiologies observed in North American patients. Most of the remaining patients fall into which of the following categories?

d. Idiopathic chronic pancreatitis

After alcohol-induced and hereditary disease, idiopathic chronic pancreatitis is the most common cause of calcifying pancreatitis in North American patients. This designation is given to those cases without a recognizable cause. Idiopathic pancreatitis accounts for about 15% of the cases and has two peaks in incidence, suggesting that differing underlying causes may exist. The first peak occurs in young adulthood and the second has an occurrence at approximately 60 years of age.