Diagnostic Ultrasound - Abdomen and Pelvis

Chronic Pancreatitis
Diagnoses: Pancreas
Intraductal Papillary Mucinous Neoplasm (IPMN) of
Pancreas
• Low-grade malignancy arising from main pancreatic duct or
side branches
• Involvement of main pancreatic duct may simulate chronic
pancreatitis
• Dilated MPD and parenchymal atrophy
Groove Pancreatitis
• Focal chronic pancreatitis in pancreatoduodenal groove
• Sheet-like fibrotic mass between pancreas and thickened
duodenal wall
• Smooth tapering of distal CBD
Autoimmune Pancreatitis
• Focal or diffuse enlargement
• Narrowed pancreatic duct
• Lack of calcifications or fluid collections
PATHOLOGY
General Features
• Etiology
○ Alcohol abuse is most common cause in USA
○ Hyperlipidemia, hyperparathyroidism (hypercalcemia),
trauma
○ Idiopathic in up to 40%
○ Gallstones not considered risk factor
○ Pathogenesis: Chronic reflux of pancreatic enzymes, bile,
duodenal contents & increased ductal pressure
– MPD or terminal duct blockage
– Edema, spasm, or incompetent sphincter of Oddi
– Periduodenal diverticulum or tumor causing
obstruction
• Genetics
○ Cystic fibrosis
○ Hereditary pancreatitis: Autosomal dominant with
incomplete penetrance
• Embryological consideration
○ Pancreas divisum: Minor papilla too small to adequately
drain pancreatic secretions, leading to chronic stasis
○ Annular pancreas: Pancreatic ductal obstruction and
stasis of secretions
Gross Pathologic & Surgical Features
• Hard atrophic pancreas with intraductal calculi & dilated
MPD
• Areas of multiple parenchymal calcifications
• Pseudocysts may be seen
Microscopic Features
• Atrophy & fibrosis of acini with dilated ducts
• Mononuclear inflammatory reaction
• Occasionally squamous metaplasia of ductal epithelium
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Recurrent attacks of epigastric pain, occasionally
radiating to back
○ Diarrhea secondary to exocrine deficiency
○ Weight loss from exocrine dysfunction, pain, or duodenal
obstruction
• Clinical profile
○ Patient with history of chronic alcoholism, recurrent
attacks of epigastric pain, diarrhea, and weight loss
○ Diagnosis usually not made until years following initial
onset of symptoms
• Labs
○ Serum and fecal markers not sensitive or specific; helpful
only in advanced disease
○ Pancreatic exocrine function hormone stimulation tests
are helpful in early disease but not widely available
Demographics
• Age
○ Mean: 5th decade
• Gender
○ Males > females
• Epidemiology
○ More common in developing countries
Natural History & Prognosis
• Pseudocyst formation
• Diabetes mellitus in ~ 1/3 of patients
• Splenic vein thrombosis, portal hypertension
• Increased incidence of pancreatic cancer: ~ 4% at 20 years
• Increased mortality: 30% at 10 years, 55% at 20 years
Treatment
• Surgical or endoscopic intervention
○ Ductal & GI obstruction
○ GI bleeding
○ Large pseudocyst or persistently symptomatic
• Conservative treatment if no major complication (e.g., pain
control, medical therapy for diabetes mellitus, etc.)
DIAGNOSTIC CHECKLIST
Consider
• Differentiate from other conditions that can cause MPD
dilatation & glandular atrophy
• May be very difficult to distinguish chronic pancreatitis with
focal fibrotic enlargement of head from pancreatic
adenocarcinoma
Image Interpretation Pearls
• Glandular atrophy, dilated MPD, and intraductal
calculi/parenchymal calcifications are best signs for chronic
pancreatitis
SELECTED REFERENCES
1. Choueiri NE et al: Advanced imaging of chronic pancreatitis. Curr
Gastroenterol Rep. 12(2):114-20, 2010
2. Siddiqi AJ et al: Chronic pancreatitis: ultrasound, computed tomography,
and magnetic resonance imaging features. Semin Ultrasound CT MR.
28(5):384-94, 2007
3. Bruno MJ: Chronic pancreatitis. Gastrointest Endosc Clin N Am. 15(1):55-62,
viii, 2005
4. Lankisch PG: The problem of diagnosing chronic pancreatitis. Dig Liver Dis.
35(3):131-4, 2003
5. Varghese JC et al: Value of MR pancreatography in the evaluation of
patients with chronic pancreatitis. Clin Radiol. 57(5):393-401, 2002
364