Diagnostics

Acute pancreatitis should be managed as a medical emergency as it is a potentially fatal condition.

Initiate fluid resuscitation as soon as this diagnosis is suspected

Simultaneously conduct diagnostics to establish the diagnosis, assess severity, and rule out potential differential diagnoses of acute abdominal pain.

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)

• Perform laboratory studies to:

  • Establish the diagnosis: serum lipase and/or amylase levels

  • Determine severity: CBC, BMP, ABG, LDH, inflammatory markers, serum calcium

  • Evaluate for the underlying etiology: liver chemistries, serum or plasma triglyceride levels

• Obtain ultrasound abdomen.

Perform contrast-enhanced CT (CECT) abdomen.

• Confirmed diagnosis

  • Perform further diagnostics as needed to determine the etiology (e.g., MRCP for suspected biliary pancreatitis).

  • Calculate severity scores of acute pancreatitis to estimate severity and prognosis.

  • In patients with severe pancreatitis, consider CECT abdomen 5–7 days after the onset of symptoms to assess for necrotizing pancreatitis.

• Indications: first-line imaging modality for all patients

• Supportive findings

  • Features of acute pancreatitis (visible in 20% of cases)

    • Enlarged hypoechoic pancreas (pancreatic edema)

    • Peripancreatic fluid and/or ascites

  • Features of biliary pancreatitis

    • Cholelithiasis and/or gallbladder sludge [8]

    • Dilated biliary tree

  • Evidence of complications: pancreatic pseudocysts, walled-off necrosis (typically > 4 weeks from symptom onset)

• Diagnostic uncertainty (e.g., typical clinical features in a patient with moderately elevated pancreatic enzymes)

• Severe pancreatitis : optimally performed > 5–7 days after symptom onset

• Lack of improvement (after > 7 days) or sudden acute deterioration

• To evaluate for underlying etiology if routine diagnostic studies are negative

• Findings

  • Features of acute pancreatitis

    • Enlargement of the pancreatic parenchyma with edema

    • Indistinct pancreatic margins with surrounding fat stranding

    • Peripancreatic free fluid

  • Evidence of complications

    • Necrotizing pancreatitis: nonenhancing areas of pancreatic parenchyma

    • Acute necrotic collections: ill-defined, heterogeneous appearance with varying densities

    • Walled-off necrosis: an encapsulated collection of necrotic material, usually occurring > 4 weeks after the onset of necrotizing pancreatitis

    • Infection: air within the pancreatic or peripancreatic tissue or fluid collections

• Indications: not routinely indicated; may be performed as part of the initial workup of undifferentiated abdominal pain

• Supportive findings

  • On abdominal x-ray

    • Sentinel loop sign: dilatation of a loop of small intestine in the left upper abdomen (duodenum or jejunum)

    • Colon cut off sign: gaseous distention of the ascending and transverse colon that abruptly terminates at the splenic flexure.

    • Calcified gallstones or pancreatic stones

  • On chest x-ray: pleural effusion, pulmonary edema suggesting ARDS

• Indications

  • In combination with MRCP in cases of suspected choledocholithiasis

  • An alternative to CT

• Supportive findings

  • Enlarged, edematous pancreas

  • Pancreatic necrosis

  • Complications (e.g., walled-off necrosis, pseudocysts)

• Indications: prior to therapeutic ERCP in suspected biliary pancreatitis

• Findings

  • Evidence of choledocholithiasis

  • Can also identify pancreatic ductal anomalies that may trigger acute pancreatitis

• Indications

  • Suspected choledocholithiasis (if MRCP or MRI are not feasible) [8]

  • To evaluate for sphincter of Oddi dysfunction in patients with recurrent pancreatitis and normal or inconclusive EUS and MRCP [30]

• Indication: evaluation of the underlying cause if routine initial workup fails to establish the etiology

• Findings: occult microlithiasis, pancreatic neoplasms, chronic pancreatitis, other pancreatic parenchymal, ductal, and ampullary disorders may be identified