Chronic pancreatitis is defined as recurrent or persistentattacks of pancreatitis, which have resulted in irreversible morphologic changes in pancreatic structure. Theseinclude scarring of the ducts with irregular areas of narrowing and dilation (beading), fibrosis of parenchyma, andloss of acinar and islet tissue. Pancreatic exocrine insufficiency and diabetes mellitus may result from unremittingchronic pancreatitis. Most patients have discrete attacksof acute symptoms occurring repeatedly, but chronic painmay be present. The causes of chronic pancreatitis include hereditary pancreatitis and milder phenotypes of cysticfibrosis associated with pancreatic sufficiency. Familial disease is caused by one of several known mutations in thetrypsinogen gene. These mutations obliterate autodigestionsites on the trypsin molecule, inhibiting feedback inhibition of trypsin digestion. Genetic testing is readily available for these mutations. Genetic testing for cystic fibrosiscan be performed, but must include screening for the lesscommon mutations associated with pancreatic sufficiency.Sweat chloride testing is less expensive and is abnormalin most. Less commonly, mutations in the SPINK1 gene, which codes for pancreatic trypsin inhibitor, and PRSS1, amutation of cationic trypsinogen, are found.
Children with chronic pancreatitis initially present withrecurring attacks of acute pancreatitis. Injury to the pancreatic ducts predisposes these children to continued attacksowing to scarring of small and large pancreatic ducts, stasisof pancreatic secretions, stone formation, and inflammation. Loss of pancreatic exocrine and endocrine tissue overtime can lead to exocrine and endocrine deficiency. Morethan 90% of the pancreatic mass must be destroyed beforeexocrine deficiency becomes clinically apparent; this is alate complication that does not occur in all cases. Chronicpain is a serious problem in most affected individuals.These patients have many episodes; many do not requirehospitalization.
Laboratory diagnosis of chronic pancreatitis is similar to acute pancreatitis but with more severe loss of pancreatic tissue it becomes less likely that the patient with elevation of amylase or lipase. Monitoring also should include looking for consequences of chronic injury, including diabetes mellitus and compromise of the pancreatic and biliary ducts. Pancreatic and biliary imaging has been accomplished by endoscopic retrograde cholangiopancreatography (ERCP). ERCP offers the possibility of therapeutic intervention to remove gallstones, dilate strictures, and place stents to enhance flow of pancreatic juice. Magnetic resonance cholangiopancreatography is an alternative to ERCP. Plain abdominal x-rays may show pancreatic calcifications. Diagnostic testing for the etiology of chronic pancreatitis should include genetic testing for hereditary pancreatitis and cystic fibrosis and sweat chloride determination.
Treatment is largely supportive. Potential but unproven therapies include the use of daily pancreatic enzyme supplements, octreotide (somatostatin) to abort early attacks, low-fat diets, and daily antioxidant therapy. Care must be taken that extreme diets do not result in nutritional deprivation. Interventional ERCP to dilate large strictures and remove stones and surgical pancreatic drainage procedures to decompress dilated pancreatic ducts by creating a side-to-side pancreaticojejunostomy may have some value.