ACUTE PANCREATITIS


GENERAL FEATURES


• Acute pancreatitis is the most common disorder of the pancreas.


• 70% to 80% of all cases are the result of gallstones or alcohol use.


• Other less common causes include peptic ulcer disease (PUD), trauma, drugs (corticosteroids, exenatide 
[Byetta], HMG Co-A reductase inhibitors, antiretrovirals), hyperlipidemia, autoimmune disorders, anatomic abnormalities, cancer, and iatrogenic causes (endoscopic retrograde cholangiopancreatog­raphy [ERCP]).


• African Americans are at increased risk for acute pancreatitis.


CLINICAL ASSESSMENT


• History


– Extreme midepigastric abdominal pain that radiates to the back is the hallmark complaint; however, may be asymptomatic (especially postoperatively).


– Generally accompanied by nausea and/or vomiting.


– Patients may recall previous episodes of right upper quadrant pain related to meals as a result of gallstones or cholecystitis.


– Providers must ask about history of alcohol use, recent surgery or procedures (ERCP), and current medications.


• Physical examination


– Splinting is common as a result of severity of abdominal pain.


– Jaundice or ichteric sclera may be noted if related to extrahepatic biliary occlusion (pancreatic cancer, common bile duct stone).


– Abdomen is generally markedly tender in midepigastrium, and bowel sounds may be decreased. 


– Abdominal wall rigidity is suggestive of peritonitis, which may be related to perforated PUD, vascular injury, or localized inflammation.


– The findings of tachycardia and hypotension in acute pancreatitis is suggestive of hypovolemic shock.


– Grey Turner's sign (ecchymosis of the flanks) or Cullen's sign (ecchymosis of the periumbilical area) are suggestive of hemorrhagic pancreatitis. 


Diagnosis


• Serum amylase and lipase levels >3 to 5 times normal in the right clinical setting help confirm acute pancreatitis. Lipase is more sensitive and specific for pancreatitis 
and remains elevated longer. However, both amylase and lipase may be normal in up to 15% of patients. Liver function tests may show 
varying levels of abnormalities.


• CBC may show leukocytosis. Decreased hematocrit may suggest an intraluminal (PUD) or peritoneal (peripancreatic vessels) bleeding.


• Albumin may be low and should be monitored as patient recovers.


• Arterial blood gas may show signs of hypoxia (low PaO₂) or acidosis.


• Calcium should be measured because saponification may cause hypocalcemia.


• Diagnostic imaging is not always necessary, but plain radiography may show a sentinel loop. CT may reveal complications or reveal etiology of pancreatitis if patient is experiencing 
worsening symptoms. Transabdom­inal ultrasonography is helpful in determining if gallbladder disease is present. ERCP is invasive and may be performed if an extrahepatic obstruction is suspected.


•  ERCP may cause further inflammation of the pancreas.


• Magnetic resonance cholangio­pancreatography is newer and does not allow for stone extraction, biliary decompression, or biopsy but does allow for visualization of the biliary tree.


• Ranson's criteria are the traditional predictive strategy for assessing the severity of acute pancreatitis; however, their predictability may be outdated. Using Ranson's criteria, three or more of the following suggest a 20% mortality risk, 8 to 11 suggest a mortality rate higher than 50%.


– On admission: age, 55 years or older; WBC, 16,000/μL; glucose, 200 mg/dL; LDH, 350 U/L; AST, 250 U/L; hypotension


– 24 to 48 hours after admission: hematocrit drops 10%; BUN rises 5 mg/dL; Ca⁺⁺, less than 8; pO₂, 60 (acidotic); fluid sequestration, more than 6.


TREATMENT


• Episodes are usually self limiting and respond to bowel rest and IV fluids; nasogastric tube is indicated only for vomiting. 


• Analgesia is important. Traditional wisdom cautions against using morphine because of potential sphincter of Oddi spasm; however, the medical literature offers little support for avoiding this narcotic when treating acute pancreatitis.


• Contrary to usual practice, enter­al feeding via a nasojejunal tube is safe and effective.


• Acid reduction in the form of parenteral proton pump inhibitors should be initiated.


• Antibiotics are only indicated for patients with poor predicted outcome on Ranson's criteria or with a known infection. The drug of choice is imipenem/cilastatin (Primaxin).


• Surgery should be considered for patients with known biliary disease or complications of acute pancre­atitis, including an abscess or pseudocyst.


• Other complications may include hemorrhage, acute respiratory distress syndrome, acites, pleural effusion, or sepsis.