Epidemiology

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Etiology

Most common causes

• Biliary pancreatitis (∼ 40% of cases; mostly caused by gallstones)
  • Blockage of the common bile duct and pancreatic duct
• Alcohol-induced (∼ 20% of cases)
• Idiopathic (∼ 25% of cases)

Other causes

• Recent endoscopic retrograde cholangiopancreatography (ERCP) procedure
• Drugs (eg, azathioprine, sulfasalazine, furosemide, valproic acid)
• Infections (eg, mumps, Coxsackie virus, Mycoplasma pneumoniae)
• Hypertriglyceridemia: caused by severe hypertriglyceridemia (> 1,000 mg/dL)
  • Pathogenesis involves toxic fatty acids that are released from triglycerides via breakdown by pancreatic lipase. Associated with primary (e.g., type V hyperlipidemia) as well as secondary (e.g., due to medications) forms of hypertriglyceridemia.
• Structural abnormalities of the pancreatic duct (strictures, cancer, pancreas divisum) or of the ampullary region (choledochal cyst, stenosis of sphincter of Oddi)
• Surgery (particularly of the stomach and biliary tract and after cardiac surgery)
• Hypercalcemia

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Pathophysiology

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Clinical features

Symptoms

• Constant, severe epigastric pain
  • Classically radiating towards the back
  • Worse after meals and when supine
  • Improves on leaning forwards
• Nausea, vomiting
• Fever

Examination findings

• General
  • Signs of shock: tachycardia, hypotension, oliguria/anuria
    • Due to distributive shock from cytokine release, and third-spacing of intravascular fluid.
  • Abdominal examination
• Abdominal tenderness, distention, guarding
  • Ileus with reduced bowel sounds and tympany on percussion
  • Ascites
  • Skin changes (rare)
    • Cullen sign: periumbilical ecchymosis and discoloration (bluish-red)
    • Grey Turner sign: flank ecchymosis with discoloration
    • Fox sign: ecchymosis over the inguinal ligament

Tip

Circulating pancreatic enzymes cause swelling of the subcutaneous tissue and localized hemorrhages. These signs, though nonspecific, suggest retroperitoneal bleeding and are associated with a poor prognosis.

• Pulmonary examination: signs of pleural effusion and/or ARDS may be present
  • Pancreatitis is a major risk factor for ARDS as it results in the release of large amounts of inflammatory cytokines and pancreatic enzymes into the circulation, which leads to infiltration of neutrophils into the pulmonary interstitium and alveolar spaces.

Tip

As the pancreas is a retroperitoneal organ, abdominal guarding may not be present with the typical hard rigidity seen in inflammation of intraperitoneal organs. Instead, the abdomen is distended and elastic on palpation.

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Diagnostics

Diagnostic criteria for acute pancreatitis

Two of the three following criteria should be met for a diagnosis of acute pancreatitis to be made.

• Characteristic abdominal pain
• ↑ Serum pancreatic enzymes: lipase or amylase ≥ 3× ULN
• Characteristic findings of acute pancreatitis on cross-sectional imaging (e.g., contrast-enhanced CT abdomen)

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Treatment

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