Chronic Pancreatitis

Snapshot

• A 32-year-old female is brought to the emergency room by her husband for severe abdominal pain. The patient reports that the pain began 4 hours again and is 10/10, sharp, and radiates to her back. She has had multiple similar episodes in the past that have resolved with opioid analgesics. She reports a 6-lbs. weight loss over the past 4 months and stools that are difficult to flush.  A CT scan demonstrastes dystrophic calcifications of the pancreas.

Introduction

• Clinical definition
  • condition characterized by a long-standing, progressive inflammation of the pancreas leading to permanent alterations in the organ’s normal structure and functions
  • damage of the organ leads to impairment of exocrine and endocrine function 
    • malabsorption leading to fat soluble vitamin (D, E, A, and K) deficiencies 
    • diabetes due to pancreas’ inability to produce insulin
• Epidemiology
  • demographics
    • alcoholism is the most common cause in the United States
• Pathogenesis
  • there are various etiologies that can lead to chronic pancreatitis 
    • alcohol abuse  
    • smoking
    • genetic causes (e.g., cystic fibrosis or hereditary pancreatitis)
    • ductal obstruction (e.g., trauma, pseudocysts, stones, tumors, or pancreas divisum)
    • tropical pancreatitis
    • systemic diseases (e.g., systemic lupus erythematous, hypertriglyceridemia, or hyperparathyroidism)
    • autoimmune pancreatitis
    • idiopathic pancreatitis
  • the pathophysiology of chronic pancreatitis is not fully understood but some theories to its development are as follows
    • proteinaceous ductal plug secondary to increased secretion of pancreatitic proteins
      • plugs acts a nidus for calcification leading to stone formation, ductal lesions, and subsequent inflammatory changes
    • ischemia likely important in exacerbating and facilitating the disease
    • lack of antioxidants (e.g., selenium, vitamin C and E, and methionine) leading to increases in free radicals
    • autoimmune mechanisms, as a number of autoimmune disorders (e.g., autoimmune pancreatitis) have been linked to chronic pancreatitis
• Associations 
• increased risk of pancreatic cancer 

Presentation

• Symptoms
  • abdominal pain
    • often epigastric with radiation to the back relieved by leaning forward
    • worse 15-30 minutes after eating
    • repeated pain attacks
  • nausea
  • vomiting
  • steatorrhea
  • constipation
  • flatulence
• Physical exam
• weight loss

Imaging

• Abdominal computed tomography (CT) with contrast
  • best initial imaging
  • positive findings include calcifications within the pancreas, ductal dilation, enlargement of the pancreas, and fluid collections (e.g., pseudocysts) adjacent to the gland  
• Magnetic resonance cholangiopancreatography (MRCP)
  • becoming the diagnostic test of choice
  • no radiation risk
  • allows for better detection of calcifications and pancreatic duct obstruction consistent with chronic pancreatitis
• Endoscopic retrograde cholangiopancreatography
• indicated in patients with no calcifications on imaging and have the potential need of therapeutic intervention

Studies 

• Laboratory studies
  • normal to minimally elevated of amylase and/or lipase
    • should not be used for the diagnosis of chronic pancreatitis
  • CBC, electrolytes, and liver functions tests
    • typically normal
    • may see elevations in serum bilirubin and alkaline phosphatase
  • HbA1c levels for evaluation of diabetes
• Pancreatic function tests
  • secretin pancreatitic function test
    • low levels of bicarbonate concentration following secretin administration indicates exocrine pancreatic insufficiency
  • stool elastase (< 200 mcg/g)
• low serum trypsinogen (< 20ng/mL)

Differential 

• Pancreatic cancer
  • differentiating factors
    • lesion will be visible on imaging with further support from ERCP findings if needed
• Acute pancreatitis
  • differentiating factors
• clinical presentation (e.g., pain characteristic) and history as well as serum lipase and/or amylase levels

Treatment

• Lifestyle and dietary modifications 
  • cessation of alcohol and tobacco
  • dietary modifications (eat small meals that are low in fat)
  • acid suppression (e.g.. proton pump inhibitor) along with pancreatic enzyme supplements (e.g., lipase) for pain management and malabsorption
  • oral hypoglycemic agents or insulin therapy if needed
  • vitamin supplementations (e.g., vitamins A, D, E, K, and B12)
• Pain management 
  • analgesics with opiates and/or nonsteroidal anti-inflammatory agents
    • indicated if pancreatic enzyme therapy fails to control pain
    • can be used with adjuvant pregabalin
  • other approaches for pain management include
    • endoscopic therapy
    • extracorporeal shock wave lithotripsy
    • celiac nerve block
• Surgery 
  • generally indicated in patients who fail medical therapy
• approaches include decompression/drainage, pancreatic resections, and denervation procedures

Complications 

• Chronic pain with addiction to analgesics
• May have exocrine and endocrine insufficiency
• Pancreatic pseudocyst
• Ductal obstruction
• Increased risk of pancreatic cancer