KEY FACTS
Terminology
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Progressive, irreversible inflammatory and fibrosing disease
Imaging
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Dilated main pancreatic duct (MPD) with intraductal calculi is highly specific for chronic pancreatitis
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Gland may be enlarged in early stage of chronic pancreatitis or during acute on chronic episode; focal or diffuse
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Focal enlargement can mimic adenocarcinoma
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Diffuse fusiform hypoechoic enlargement in autoimmune type > focal or multifocal ± ductal dilation in focal type
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Later: Inflammation and fibrosis causes atrophy
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Calcification/calculi: ~ 90% of calcific pancreatitis caused by alcoholism
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EUS best imaging test to detect early changes of chronic pancreatitis
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MRCP best to visualize dilated MPD and side branches
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Assess for ductal disruption: Continuity of MPD with pseudocyst, bowel, or pleural space
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MR with contrast helpful to distinguish tumor from enlargement related to inflammation
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CT best to evaluate extent of calcifications and inflammation related to acute on chronic pancreatitis
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Complications: Pseudocyst
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Color Doppler for vascular complications: Portosplenic venous thrombosis (5%); arterial pseudoaneurysm
Top Differential Diagnoses
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Infiltrating pancreatic carcinoma
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Acute pancreatitis
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Autoimmune pancreatitis
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Intraductal papillary mucinous neoplasm
Pathology
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Alcohol abuse is most common cause in USA; gallstones not considered risk factor
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Idiopathic in up to 40%; hyperlipidemia, hyperparathyroidism, hypercalcemia, trauma
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Cystic fibrosis, hereditary pancreatitis
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Pancreas divisum or annular pancreas
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Autoimmune IgG4 related
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Clinical Issues
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Males > females; mean: 5th decade
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Recurrent attacks of epigastric pain, occasionally radiating to back, diarrhea, weight loss, biliary or duodenal obstruction, diabetes
Diagnostic Checklist
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May be very difficult to distinguish chronic pancreatitis with focal fibrotic enlargement of head from pancreatic adenocarcinoma
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Glandular atrophy, dilated duct and intraductal calculi or parenchymal calcifications are best signs for chronic pancreatitis
Scanning Tips
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Follow pancreatic duct; use higher resolution transducer for the detection of intraductal calculi
, intraductal stones 
, and parenchymal calcifications 
within the atrophic parenchyma.
with intraductal calculus 
and parenchymal calcifications 
, consistent with chronic pancreatitis. A bilobed fluid collection in the head 
is consistent with a small pseudocyst. The parenchyma 
has normal size and echogenicity.
without intraductal calculi. The gland is normal in size in this example.
with intraductal calcifications in the head/neck region 
. There is a fatty liver 
.
