Acute Pancreatitis

Acute pancreatitis is a reversible inflammatory process of the pancreas that may be associated with a systemic inflammatory response that can cause multiorgan impairment. Lipase testing should be ordered instead of amylase for diagnosis.

Diagnosis

Indications for Testing

Abdominal pain in epigastrium

Laboratory Testing

  • Diagnostic criteria (International Association of Pancreatology [IAP]/American Pancreatic Association [APA], 2013)
    • Upper abdominal pain
    • Serum lipase (preferred) or amylase >3 times the upper limit of normal, and/or
    • Imaging criteria
  • Testing
    • Lipase
      • More sensitive and specific for pancreatic disease than amylase
      • Serial measures are not necessary as they do not provide prognostication
    • Amylase
    • CBC – leukocytosis common in severe disease
    • Metabolic panel
      • Panel includes sodium, potassium, blood urea nitrogen (BUN), creatinine, calcium, glucose, and HCO3
      • Calcium, BUN, and glucose aberrations may be associated with prognosis
    • C-reactive protein (CRP)
      • Concentration ≥150 mg/dL within first 72 hours after presentation suggests acute necrotizing pancreatitis
      • Order 48 hours after illness onset to prevent false negatives
    • Procalcitonin
      • May help differentiate between mild and severe disease
      • Should be obtained at admission
    • Trypsin
      • Indicator of pancreatic damage
      • Concentrations are significantly elevated in acute pancreatitis
    • Alanine aminotransferase (ALT)
      • >150 U/L within 48 hours of symptom onset distinguishes biliary pancreatitis (85% positive predictive value)

Imaging Studies

  • Confirm diagnosis or assess local complications (eg, fluid collections, necrosis)
    • Ultrasound
    • Computed tomography (CT)
    • Magnetic resonance cholangiopancreatography (MRCP)
    • Endoscopic retrograde cholangiopancreatography (ERCP)

Prognosis

  • Prognostic criteria
    • IAP/APA, 2013
      • Systemic inflammatory response syndrome (SIRS) is recommended for prognostic assessment at admission
      • SIRS that persists >48 hours is associated with worse outcomes (multiorgan failure, mortality)
      • Prognosis should involve assessment of
        • Host risk factors
        • Clinical risk factors (eg, SIRS)
        • Therapeutic response
    • 2012 revised Atlanta classification – severity grades
      2012 Revised Atlanta Classification – Severity Grades of Acute Pancreatitisa

      Mild

      No organ failure; no systemic or local complications

      Moderately severe

      Transient organ failure (resolves in 48 hrs); systemic or local complications but no persistent organ failure

      Severe

      Organ failure (persistent, >48 hrs), involving either single or multiple organs

      aAdapted from Banks, 2013

    • Ranson criteria
      Ranson Criteria Scoring – One Point for Each Criterion Met

      At admission or diagnosis

      Age – >55 yrs

      WBC count – >16,000/mm3 (>16.0 x 109/L)

      Blood glucose – >200 mg/dL (>11.1 mmol/L)

      Serum lactate dehydrogenase – >350 U/L

      AST – >250 U/L

      At 48 hrs

      Hematocrit decrease – ≥10%

      BUN increase – ≥5 mg/dL (≥1.8 mmol/L), despite IV fluids

      Serum calcium – <8 mg/dL (<2 mmol/L)

      Base deficit – >4 mEq/L

      Fluid sequestration – >6,000 mL

      PaO2 – <60 mm Hg

      AST = aspartate aminotransferase; BUN = blood urea nitrogen; PaO2 = partial arterial oxygen tension; WBC = white blood cell

      Source: Basit, 2020

    • Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scale
      • Equation includes the following factors
        • Age
        • Rectal temperature
        • Mean arterial pressure
        • Heart rate
        • Partial arterial oxygen tension (PaO2)
        • Arterial pH
        • Serum potassium
        • Serum sodium
        • Serum creatinine
        • Hematocrit
        • White blood cell (WBC) count
        • Chronic health status
        • Glasgow Coma Scale score
    • Glasgow prognostic criteria (Imrie scoring system)
      Glasgow Prognostic Criteria (Imrie Scoring System)

      Criterion

      Scoring – 1 point for each criterion met 48 hrs after admission

      • Age – <55 yrs
      • 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
      • AST or 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)

      Prediction of adverse outcome in severe pancreatitis

      • Organ dysfunction – APACHE II score ≥8 (60% sensitive, 85% specific)
      • MODS at 72 hrs – >3
      • SOFA score at 48 hrs – >4
      • Ranson score at 48 hrs – >3
      • Modified Glasgow score at 48 hrs – ≥3

      Prediction of local complications

      • Hematocrit – >44%
      • BMI – >30 kg/m2
      • Balthazar CT grade of C-E at 1 wk (85% sensitive, 100% specific)
      ALT = alanine aminotransferase; AST = aspartate aminotransferase; APACHE II = Acute Physiology and Chronic Health Evaluation II; BMI = body mass index; CT = computed tomography; MODS = multiple organ dysfunction score; PaO2 = partial arterial oxygen tension; SOFA = sequential organ failure assessment; WBC = white blood cell
    • BALI score​
      BALI Score

      Age

      ≥65 yrs

      Blood urea nitrogen level

      ≥25 mg/dL (8.9 mmol/L)

      Lactate dehydrogenase level

      ≥300 U/L (5.0 µkat/L)

      Interleukin-6

      ≥300 pg/mL

    • CT severity index (Balthazar criteria)
      CT Severity Index (Balthazar Criteria) Scoring – CT Grade + Necrosis Score
      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
      ≤30% 2 points
      30-50% 4 points
      >50% 6 points

Differential Diagnosis

  • Acute cholecystitis
  • Acute coronary syndromes
  • Aortic dissection
  • Appendicitis
  • Cholangitis
  • Diabetic ketoacidosis
  • Ectopic pregnancy
  • Gastric outlet obstruction
  • Gastric volvulus
  • Intestinal obstructions
  • Mesenteric ischemia
  • Nephrolithiasis
  • Pancreatic cancer
  • Perforated duodenal/gastric ulcer
  • Tubo-ovarian abscess

Background

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 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

  • Signs and symptoms
    • Gastrointestinal
      • Sudden upper abdominal pain – may radiate to back, flank, lower abdomen; worsened by ingestion of food
      • Nausea, emesis
      • Retroperitoneal hemorrhage – indicates poorer prognosis
        • Grey Turner sign – gray 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 formation, abscess formation, ascites
    • Intestinal – paralytic ileus, gastrointestinal hemorrhage, bowel infarction
    • Hepatobiliary – jaundice, obstruction of the common bile duct
    • Metabolic 
    • Hematological
      • Disseminated intravascular coagulation
      • Vein thrombosis – portal, mesenteric, splanchnic
    • Renal – acute renal failure
    • Cardiovascular – circulatory failure (shock)
    • Respiratory – hypoxic acute respiratory failure

ARUP Laboratory Tests

Primary Tests

Aid in diagnosing acute pancreatitis

Test included in Ranson criteria

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

Preferred test to detect acute phase inflammation (eg, autoimmune diseases, connective tissue disease, rheumatoid arthritis, infection, or sepsis)

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

Specific indicator of pancreatic damage

Patients with acute pancreatitis have significantly elevated concentrations

Trypsin concentrations are not diagnostic for carcinoma of the pancreas

Results obtained with different assay methods or kits cannot be used interchangeably

Related Tests

Screening test to evaluate kidney function

Prognostic score in Ranson criteria

Diagnose biliary etiology for acute pancreatitis

Serum lipase is preferred test; amylase is less sensitive and specific for pancreatic disease than lipase

No role in assessing severity

Rule out macroamylasemia as cause of elevated amylase

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

For information on body fluid reference ranges and/or interpretive guidance, visit http://aruplab.com/bodyfluids/

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

For information on body fluid reference ranges and/or interpretive guidance, visit http://aruplab.com/bodyfluids/

Rule out salivary amylase as cause of elevated amylase

Medical Experts

Contributor

Genzen

Jonathan R. Genzen, MD, PhD
Associate Professor of Clinical Pathology, University of Utah
Chief Operations Officer: Medical Director, Automated Core Laboratory, ARUP Laboratories

References

Additional Resources