Pancreas

Introduction

• Acute onset of pancreatic and peripancreatic inflammation
• Rate is rising (10-45 cases / 100,000), 5% mortality rate.
• Classification:

  • Severity	Criteria
    Mild Pancreatitis (Most Cases)	Acute pancreatitis that does not meet "severe" criteria".
    Severe Pancreatitis - 20% of acute pancreatitis - up to 20% mortality	Organ failure     - hypoxemia     - hypotension     - renal failure OR Complications:    - Pancreatic Necrosis    - Fluid collections

• Premature activation of intracellular pancreatic trypsinogen to trypsin conversion (activation).
  • Triggers inflammatory cascade, causing capillary leak --> Can cause SIRS

Causes

• 80% of all acute pancreatitis are from Gall Stones or EtOH

• Causes of Pancreatitis

  G - Gall Stones (45%) (MOST COMMON)    - Microlithiasis E - Ethanol (35%)  (MOST COMMON) T - Tumors (choledochocele) S - Steroids M - Mumps A - Autoimmune (IgG4, Polyarteritis Nodosa?, SLE?)    - (Other infections: viral [CMV, MUMPS], parasitic [toxoplasma, Ascaris lumbricoides]) S - Scorpion bite H - Hypertriglyceridemia (TG > 5.6) Hypercalcemia E - ERCP (post-ERCP), Emboli, Ischemia D - Drugs SAND Mnemonic S - Simvastatin A - Azathioprine, 6-MP N - NSAIDS? D - Diuretics (Furosemide, hydrochlorthiazide) Mesalamine, asparaginase, didanosine   Others: - Pancreas divisum (two congenital pancreatic ducts) - Genetic, Ischemia

Symptoms

• Sudden onset pain in epigastric region with radiation to the back.
  • (more comfortable seated position than supine).
• Nausea, vomiting, fever.
• Pleural Effusions --> dyspnea. (from capillary leak).

Diagnostic Criteria

• Diagnostic Criteria for Acute Pancreatitis
  Need at least two of:     1.  Typical clinical symptoms     2.  Elevated serum amylase and/or lipase level> 3x ULN     3.  Typical findings on cross-sectional imaging.

  
   
• Lipase has a longer half-life, MUCH more specific.
• Amylase is less specific (can see in salivary glands, fallopian tubes rises sooner.
  • Non-specific, also seen in:
    • Perforated peptic ulcer
    • Intestinal ischemia
    • Acute hepatitis or cholecystitis
    • Rupture ectopic pregnancy
    • Parotidis
    • CKD
  • Macroamylasemia
    • Bening condition - multimers of amylase that are poorly filtered (need to do SPEP to find out). 
  • Gullo Syndrome
    • Rare cause of benign amylase and sometimes even lipase elevations.
• Contrast CT - only if clinical picture is not clear.
  • Pancreatic or peripancreatic edema (+inflammatory stranding), fluid collections
  • Pancreatic necrosis (but rare on initial imaging). 
  • Splenic vein thrombosis? 

Prognosis

• Ranson Criteria  (need parameters on admission + 48hrs later).
  • Problem: Complexity, and cannot make initial analysis.
• Apache Score (MORE COMMON)
  • The Acute Physiology and Chronic Health Evaluation (APACHE) II
  • More accurate than Ranson, but cumbersome. (i.e. need ABG, etc...)
• Hemoconcentration
  • Potential predictor of morbidity and mortality (marker of capillary leak).
  • **Elevated BUN (serum)** Most important, most reliable, can trend.
  • Elevated Creat
  • Elevated Hematocrit
• Others:
  • Medical comorbidities
  • >75, 
  • BMI > 30

Management

• ADMIT ALL
  • ICU if hemodynamically unstable or breathing challenges
• Require:
  • Narcotic analgesia
  • Bowel rest (NPO)
  • Aggressive early fluids (Pancreas can sequester a lot of fluid) --> decrease ECV --> AKI + other organs.
    • High risk of necrotizing pancreatitis (contrast CT often demonstrates inflammation and hypoperfusion).
    • Monitor hypovolemia signs (tachycardia, hypotension, dry MM, hematocrit).
    • Rehydration helps prevent organ failure.
• Other therapies:

1. NG Tube  --> NOT INDICATED

• Usually not needed, unless have ileus as a result from pancreatitis

2. ERCP --> USUALLY NOT

• ERCP: AVOID, can worsen: in gall stones or worsening sympsoms + rising liver chemistry
• ONLY in two scenarios:
  • 1.  Concominant ascending cholangitis (fever, RUQ pain, and jaundice)
  • 2.  Gallstone pancreatitis who is not improving clinically and has worsening liver chemistry tests.

3. Starting: Naso-Jejunal feeding

• Criteria: Start as soon as feasible NJ feeding, especially if no signs of improvement in first 72-92hrs.
• Avoid IV nutrition (high risk fungemia, bacteremia).

4. Surgery

• Cholecystectomy indicated prior to discharge if pt has gall stone pancreatitis, and no other complications.  (previously done as O/P once pancreas "cools off")
• Also done if pancreas is necrotic, due to high risk of mortality.  But usually need repeat OR to keep removing necrotic tissue.  Various drains are currently investigated.

5. Antibiotics --> NOT INDICATED

• In the past used carbapenems, but now not indicated, even if necrosis is present.
• Studies: NO BENEFIT on mortality (predisposis to intra-abdominal fungal infections)
• If significant pancreatic necrosis --> can consider percutaneous fine-needle aspiration (culture + Gram stain).
  • Abx only for culture-proven infected necrosis of the pancreas.
  • If documented necrotizing pancreatitis and develop clinical instability (Fever, Hypotension)
    • Must sample pancreatic bed (endoscopically, percutaneously, or surgical).
    • May need drainage, if infected.

6. Probiotics --> worsen outcomes

Complications

• Pseudocysts (Most Common)
  • Fluid collection without solid degree (no epithelial layer)  - Most common complication
    • Often walled off pancreatic necrosis
  • Pancreatic fluid collections due to destruction of main pancreatic duct or branches.
  • Often have continued abdominal pain, failure to thrive, hospitalization etc..
    • Can have mass effect on stomach
  • Pseudocysts typically resolve spontaneously, and do not need treatment.
  • If persist or have mass effect: surgical decompression, percutaneously, endoscopically.
• Leaking Pancreatic Ducts (30%)
  • If untreated, can develop fistulas.
  • Treated with:
    • Endoscopic stenting.
    • Can use octreotide to decrease secretions. 
    • Pancreatic enzymes to replace what is lost.
    • Bowel rest.
• Splenic Vein Thrombosis
  • Anticoagulation not recommended.
  • Secondary to inflammation around that vein in pancreas.
  • Can cause gastric varices.
• Diabetes
  • If lost a lot of pancreas.

Treatment

1. IV HYDRATION -> Aggressive!!!
   • High risk of necrotizing pancreatitis (contrast CT often demonstrates inflammation and hypoperfusion).
   • Monitor hypovolemia signs (tachycardia, hypotension, dry MM, hematocrit).
   • Rehydration helps prevent organ failure.
2. Notes On Other Therapies
   1. Antibiotics? --> NOT INDICATED in acute pancreatitis, even if necrosis is present.  In the past used carbapenems.
      • Studies show no benefit of prophylactic abx in severe necrotic pancreatitis.  (abx raise risk of abdominal fungal infections)
      • If significant pancreatic necrosis --> can consider percutaneous fine-needle aspiration (culture + Gram stain).
      • Treat only if culture-proven infected necrosis of the pancreas.
   2. ERCP ?
      • ->  Can worsen pancreatitis.  Only indicated if gallstone pancreatitis and worsening liver chemistry + instability (or if concerning for ascending cholangitis).
   3. NG suction? --> NOT INDICATED
      • Early feeding decreases hospital stay, mortality.  No need to NG suction.
   4. Probiotics contraindicated: increases mortality.
   5. Surgery:
      • If necrotic, high mortality.
      • However have to repeat OR many times, keep taking out necrotic tissue.
      • Investigated various drains.

         

References / Further Reading

• Banks PA, Freeman ML; Practice Parameters Committee of the American College of Gastroenterology. Practice guidelines in acute pancreatitis. Am J Gastroenterol. 2006;101(10):2379-2400. PMID: 17032204
• MKSAP 16