Chronic Pancreatitis

1. Pathophysiology
   1. Recurrent episodes of Acute Pancreatitis
   2. Pain episodes may resolve once pancreatic function fails completely
2. Causes
   1. Chronic Alcoholism (most common U.S. cause)
   2. Idiopathic (25% of cases)
   3. Autoimmune Pancreatitis related conditions
      1. Inflammatory Bowel Disease
      2. Sjogren's Syndrome
      3. Primary biliary Cirrhosis
   4. Hypertriglyceridemia
   5. Hyperparathyroidism or Hypercalcemia
   6. Hereditary Pancreatitis
   7. Hemochromatosis
   8. Cystic Fibrosis
   9. Occult neoplasm or other causes of pancreatic obstruction
   10. Chronic Renal Failure
3. Symptoms
   1. Abdominal Pain
      1. Chronic and disabling Abdominal Pain
      2. Midepigastric postprandial pain with radiation to the back
      3. Relieved on sitting upright or leaning forward
   2. Bowel malabsorption
      1. Steatorrhea
      2. Weight loss
      3. Vitamin Deficiency (rare)
         1. Deficiency of Vitamins A,D,E,K
         2. Vitamin B12 Deficiency
4. Labs
   1. Pancreatic Enzymes
      1. Serum Amylase normal
      2. Serum Lipase normal
      3. D-Xylose urinary excretion normal
      4. Pancreatic Exocrine function abnormalities (not typically done)
         1. Bentiromide test may be abnormal
         2. Secretin Stimulation Test abnormal in pancreatic exocrine insufficiency
            1. Peak bicarbonate concentration: Abnormal if <80 mEq/L in duodenal secretions
         3. Serum trypsinogen (Abnormal if <20 ng/ml)
   2. Liver Function Tests
      1. Increased Serum Bilirubin and Alkaline Phosphatase if obstruction present
   3. Stool studies (Late findings)
      1. Steatorrhea (abnormal if fecal fat concentration >9.5% or >7 grams/day)
      2. Fecal elastase (Abnormal if <200 mcg/gram of stool)
   4. Electrolytes
      1. Glucose Intolerance or Diabetes Mellitus (50% of patients)
5. Differential Diagnosis
   1. Acute Cholecystitis
   2. Acute Pancreatitis
   3. Mesenteric Ischemia
   4. Peptic Ulcer Disease
   5. Pancreatic Carcinoma
6. Imaging
   1. Abdominal XRay
      1. Pancreatic calcifications (30-60% of cases)
   2. CT Abdomen (preferred first-line test)
      1. Pancreatic Pseudocyst
      2. Pancreatic duct dilatation
7. Diagnosis
   1. Endoscopic ultrasound
      1. Preferred over ERCP due to much lower complication rate and high sensitivity
      2. Can be combined withg FNA biopsy to evaluate mass lesions for malignancy
   2. Endoscopic Retrograde Cholangiopancreatography (ERCP)
      1. Irregular dilation of main pancreatic duct
      2. Pruning of pancreatic duct branches
8. Management: Medical
   1. Treat exacerbations as in Acute Pancreatitis
   2. Pain control
      1. Tylenol
      2. NSAIDs
      3. Cautious use of Narcotics (high abuse potential and common outcome in chronic cases)
   3. Avoid exacerbating factors
      1. Abstain from Alcohol use
      2. Avoid Tobacco
      3. Follow Low Fat Diet
      4. Eat smaller meals
   4. Malabsorption Management (if steatorrhea)
      1. Pancreatic enzyme replacement (40,000 units of Lipase with Proton Pump Inhibitor)
      2. Consider one-time DEXA Scan and Vitamin D level
   5. Glucose Intolerance management
9. Management
   1. ERCP Indications
      1. Painful pancreatic duct stricture or gall stones
      2. Pseudocysts (ERCP for drainage)
   2. Surgical Indications
      1. Intractable pain refractory to ERCP and other measures
      2. Suspected Pancreatic Cancer
      3. Compression from surrounding tissue
   3. Surgical procedures: Decompression for large duct disease
      1. Lateral pancreaticojejunostomy
      2. Cystenterostomy (for pseudocyst)
   4. Surgical procedures: Resective for pancreatic tumor or small duct disease
      1. Whipple Procedure (most common surgery for Chronic Pancreatitis)
         1. Pain relief in 85% of Chronic Pancreatitis cases and <3% mortality
      2. Total pancreatectomy (procedure of last resort)
10. Complications
    1. Vitamin B12 Malabsorption
       1. Alcoholism
       2. Cystic Fibrosis
    2. Diabetes Mellitus (occurs in most patients within 5 years of onset Chronic Pancreatitis)
    3. Non-Diabetic Retinopathy
       1. Vitamin A Deficiency
       2. Zinc Deficiency
    4. Gastrointestinal Bleeding
    5. Pancreatic carcinoma (very high risk)
    6. Subcutaneous Fat Necrosis
    7. Narcotic addiction (secondary to Chronic Pain)
11. References
    1. Forsmark in Feldman (2006) Sleisenger & Fordtran's Gastrointestinal and Liver Disease, Chap 57
    2. Ahmad (2006) Curr Probl Surg 43: 127-238
    3. Fry (2007) Am J Surg 194: S45-S52
    4. Nair (2007) Am Fam Physician 76: 1679-94