Pancreatitis, Acute

Diagnosis

Indications for Testing

  • Abdominal pain in epigastrium

Laboratory Testing

  • Amylase, lipase – ≥3 times normal level
    • Lipase more sensitive and specific for pancreatic disease
    • No role in assessing severity; not helpful when measured on a daily basis
  • CBC – leukocytosis common in severe disease
  • Metabolic panel (sodium, potassium, BUN, creatinine, calcium, glucose, HCO3)
    • Calcium, BUN and glucose may be associated with prognosis
  • C-reactive protein – concentration ≥150 mg/dL within the first 72 hours after presentation indicates acute necrotizing pancreatitis (sensitivity 80-85%, specificity 90%)
    • Recommend waiting 48 hours after illness before obtaining (to prevent false negatives)
  • Procalcitonin – may have value in differentiating between mild and severe disease
    • Should be obtained at admission

Imaging Studies

  • US/CT/ERCP – all used to confirm diagnosis or to assess local complications such as fluid collections and neurosis

Prognosis

  • Prognostic criteria
    • Ranson criteria  
      • At admission or diagnosis
        • Age <55 years
        • WBC count <16,000/mm3 (16.0x109/L)
        • Blood glucose <200 mg/dL (11.1 mmol/L)
        • Serum lactate dehydrogenase <350 U/L
        • AST <250 U/L
      • During initial 48 hours
        • Hematocrit decrease <10%
        • BUN increase <5 mg/dL (1.8 mmol/L)
        • Serum calcium <8 mg/dL (2 mmol/L)
        • Base deficit <4 mmol/L (4 mEq/L)
        • Fluid sequestration <6,000 mL
        • Partial arterial oxygen tension (PaO2) <60 mm HG
        • Scoring: one point for each criterion met
    • APACHE II scale
      • Equation includes the following factors: age, rectal temperature, mean arterial pressure, heart rate, PaO2, arterial pH, serum potassium, serum sodium, serum creatinine, hematocrit, WBC count, chronic health status, and Glasgow Coma Scale score
    • CT severity index (Balthazar criteria)
      • CT grade
        • A – normal pancreas (0 points)
        • B – edematous pancreas (1 point)
        • C – B plus mild extrapancreatic changes (2 points)
        • D – severe extrapancreatic changes plus one fluid collection (3 points)
        • E – multiple of extensive fluid collections (4 points)
        • Necrosis score:
          • None (0 points)
          • <One-third (2 points)
          • >One-third but <one-half (4 points)
          • >One-half (6 points)
        • Scoring: CT grade + necrosis score
    • Glasgow prognostic criteria (Imrie scoring system)
      • Age <55 years
      • WBC count <15,000/mm3 (15.0x109/L)
      • Blood glucose <180 mg/dL (10 mmol/L) in patients without diabetes
      • Serum lactate dehydrogenase <600 U/L
      • Serum aspartate transaminase (AST) or alanine transaminase (ALT) <100 U/L
      • Serum calcium <8 mg/dL
      • PaO2 <60 mm Hg
      • Serum albumin <3.2 g/dL (32 g/L)
      • Serum urea <45 mg/dL (16.0 mmol/L)
      • Scoring: one point for each criterion met 48 hours after admission
    • Predictions of adverse outcome in severe pancreatitis
    • Prediction of local complications
      • Hematocrit – >44%
      • Body mass index (BMI) – >30
      • Balthazar CT grade of C–E at 1 week (85% sensitive, 100% specific)

Differential Diagnosis

  • Acute cholecystitis
  • Perforated duodenal/gastric ulcer
  • Mesenteric ischemia
  • Aortic dissection
  • Acute coronary syndromes
  • Intestinal obstructions
  • Nephrolithiasis
  • Appendicitis
  • Ectopic pregnancy

Clinical Background

Acute pancreatitis is a reversible inflammatory process of the pancreas.

Epidemiology

  • Incidence – 30-40/100,000 in the U.S.
  • Age – peaks in 40s
  • Sex
    • Gallstone-induced pancreatitis, M<F
    • Alcohol-induced pancreatitis, M>F

Risk Factors

Pathophysiology

  • Inappropriate or premature activation of trypsinogen thought to be the initiating event
  • Early stages are characterized by interstitial edema of pancreatic parenchyma and necrosis of peripancreatic fat
  • In 20% of patients, pancreatitis progresses to coagulation necrosis of glandular elements

Clinical Presentation

  • Gastrointestinal
    • Sudden upper abdominal pain – may radiate to flank, lower abdomen
    • Nausea, emesis
    • Retroperitoneal hemorrhage – indicates poorer prognosis
      • Grey Turner sign – grey discoloration over flank
      • Cullen sign – bruising in and around umbilicus
    • Constitutional – fever
    • Cardiopulmonary – respiratory distress, hypotension, and tachycardia
    • Neurologic – encephalopathy
    • Renal – diminished urine output
  • Potential complications
    • Pancreatic – acute fluid collection, necrosis, pseudocyst, abscess, ascites
    • Intestinal – paralytic ileus, GI hemorrhage
    • Hepatobiliary – jaundice, obstruction of the common bile duct, portal vein thrombosis
    • Systemic
    • Renal – acute renal failure
    • Cardiovascular – circulatory failure (shock)
    • Respiratory – hypoxic acute respiratory failure

Treatment

  • Hospitalization with intravenous fluids
  • Remove anatomic causes (eg, gallstones)
  • Antibiotics in severe pancreatitis

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Amylase, Serum or Plasma 0020013
Method: Quantitative Enzymatic

Aid in diagnosing acute pancreatitis; usually elevated in acute pancreatitis

No role in assessing severity

False positives occur in macroamylasemia, renal failure, esophageal perforation, pregnancy and mumps parotitis

 
Lipase, Serum or Plasma 0020014
Method: Quantitative Enzymatic

Aid in diagnosing acute pancreatitis (>90% sensitive)

More sensitive and specific for pancreatic disease than amylase

No role in assessing severity

False positives occur in renal failure, intestinal perforation

 
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Test included in Ranson criteria

   
Comprehensive Metabolic Panel 0020408
Method: Quantitative Ion-Selective Electrode/Quantitative Enzymatic/Quantitative Spectrophotometry

Test used in prognostic scoring

Panel includes albumin; alkaline phosphatase; aspartate aminotransferase; alanine aminotransferase; bilirubin, total; calcium; carbon dioxide; creatinine; chloride; glucose; potassium; protein, total; sodium; and urea nitrogen

   
Procalcitonin 0020763
Method: Immunofluorescence

Determine presence of acute necrotizing pancreatitis

Procalcitonin levels measured shortly after the systemic infection process begins (usually <6 hours) may still be low because other noninfectious conditions also induce procalcitonin

Review procalcitonin levels of 0.50–2.00 ng/mL in light of patient’s specific clinical background and individual condition

 
C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Use in the first 72 hours to determine presence of acute necrotizing pancreatitis (sensitivity 80-85%, specificity 90%)

Obtain ≥48 hours after illness begins to help prevent false negatives

 
Trypsin-Like Immunoreactivity 0070003
Method: Quantitative Radioimmunoassay

Determine presence of exocrine pancreatic insufficiency

92.0-850.0 ng/mL suggestive of acute pancreatitis

Results should be correlated with clinical presentation and other diagnostic data

   
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Urea Nitrogen, Serum or Plasma 0020023
Method: Quantitative Spectrophotometry

Prognostic score in Ranson criteria

Bilirubin, Direct and Total, Serum or Plasma 0020426
Method: Quantitative Spectrophotometry

Diagnose biliary etiology for acute pancreatitis

Bilirubin, Direct, Serum or Plasma 0020033
Method: Quantitative Spectrophotometry

Bilirubin component test

Bilirubin, Total, Serum or Plasma 0020032
Method: Spectrophotometry

Bilirubin component test

Amylase, Urine 0020471
Method: Quantitative Enzymatic

Rule out macroamylasemia as cause of elevated amylase

Amylase, Body Fluid 0020506
Method: Quantitative Enzymatic

Not useful in diagnosis of disease; however, may help identify pancreatitis as a cause

Lipase, Fluid 0020715
Method: Quantitative Enzymatic

Not useful in diagnosis of disease; however, may help identify pancreatitis as a cause

Amylase, Isoenzymes 0020804
Method: Quantitative Enzymatic

Rule out salivary amylase as cause of elevated amylase

Macroamylase Determination 2004464
Method: Quantitative Ultrafiltration/Quantitative Enzymatic