Pancreatitis, Acute

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
  - Organ dysfunction – APACHE II score ≥8 (60% sensitive, 85% specific)
  - Multiple organ dysfunction score (MODS) at 72 hours >3
  - Sequential organ failure assessment (SOFA) score at 48 hours >4
  - Ranson score at 48 hours >3
  - Modified Glasgow score at 48 hours ≥3
- 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

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

Hepatobiliary
- Gallstones/choledocholithiasis
- Chronic alcohol consumption
- Hepatobiliary tumors (rare)
Drug-induced – estrogen, corticosteroids, isoniazid, metronidazole, azathioprine
Iatrogenic – surgery, post endoscopic retrograde cholangiopancreatography (ERCP)
Infection – viral, bacterial, fungal
Metabolic
- Hyperlipidemia
- Hypercalcemia, hyperparathyroidism
Autoimmune – eg, systemic lupus erythematosus
Genetic – cystic fibrosis, mitochondrial disease, mutations in PRSS1 or SPINK1 genes
Congenital anomalies – pancreas divisum
Tumor
Trauma/ischemia

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
  - Metabolic
    - Malnutrition
    - Hypocalcemia
    - Hypoglycemia
  - Hematological
    - Disseminated intravascular coagulation
    - Portal vein thrombosis
- 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

Tests generally appear in the order most useful for common clinical situations

Test name: Amylase, Serum or Plasma

ARUP #: 0020013

Methodology: Quantitative Enzymatic

Use:

Aid in diagnosing acute pancreatitis; usually elevated in acute pancreatitis

No role in assessing severity

Limitations:

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

Test name: Lipase, Serum or Plasma

ARUP #: 0020014

Methodology: Quantitative Enzymatic

Use:

Aid in diagnosing acute pancreatitis (>90% sensitive)

More sensitive and specific for pancreatic disease than amylase

No role in assessing severity

Limitations:

False positives occur in renal failure, intestinal perforation

Test name: CBC with Platelet Count & Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count with Flow Cell Differential

Use:

Test included in Ranson criteria

Test name: Comprehensive Metabolic Panel

ARUP #: 0020408

Methodology: Refer to individual components

Use:

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

Test name: Procalcitonin

ARUP #: 0020763

Methodology: Immunofluorescent

Use:

Determine presence of acute necrotizing pancreatitis

Limitations:

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

Test name: C-Reactive Protein

ARUP #: 0050180

Methodology: Quantitative Immunoturbidimetric

Use:

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

Limitations:

Obtain greater than or equal to 48 hours after illness begins to help prevent false negatives

Test name: Trypsin-Like Immunoreactivity

ARUP #: 0070003

Methodology: Quantitative Radioimmunoassay

Use:

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

Test name: Urea Nitrogen, Serum or Plasma

ARUP #: 0020023

Methodology: Quantitative Spectrophotometry

Comments:

Prognostic score in Ranson criteria

Test name: Bilirubin, Direct & Total, Serum or Plasma

ARUP #: 0020426

Methodology: Quantitative Spectrophotometry

Comments:

Diagnose biliary etiology for acute pancreatitis

Test name: Bilirubin, Direct, Serum or Plasma

ARUP #: 0020033

Methodology: Quantitative Spectrophotometry

Comments:

Bilirubin component test

Test name: Bilirubin, Total, Serum or Plasma

ARUP #: 0020032

Methodology: Spectrophotometry

Comments:

Bilirubin component test

Test name: Amylase, Urine

ARUP #: 0020471

Methodology: Enzymatic

Comments:

Rule out macroamylasemia as cause of elevated amylase

Test name: Amylase, Body Fluid

ARUP #: 0020506

Methodology: Quantitative Enzymatic

Comments:

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

Test name: Lipase, Fluid

ARUP #: 0020715

Methodology: Quantitative Enzymatic

Comments:

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

Test name: Amylase, Isoenzymes

ARUP #: 0020804

Methodology: Quantitative Enzymatic

Comments:

Rule out salivary amylase as cause of elevated amylase

Test name: Pancreatitis, Idiopathic (CFTR, PRSS1, SPINK1) Sequencing

ARUP #: 2002005

Methodology: Polymerase Chain Reaction/Sequencing

Comments:

Order in idiopathic recurrent pancreatitis to determine genetic predisposition to the condition

Clinical sensitivity 45% for idiopathic chronic pancreatitis

Test name: Pancreatitis, Hereditary (PRSS1) Sequencing

ARUP #: 2002016

Methodology: Polymerase Chain Reaction/Sequencing

Comments:

Order in children with pancreatitis or in affected adults with a positive family history

Sensitivity 80% for hereditary pancreatitis

Test name: Pancreatitis, Idiopathic (SPINK1) Sequencing

ARUP #: 2002012

Methodology: Polymerase Chain Reaction/Sequencing

Comments:

Order in adults with idiopathic pancreatitis if other components of the panel have already been performed (eg, CFTR, PRSS sequencing)

Clinical sensitivity 17% for idiopathic chronic pancreatitis

Test name: Macroamylase Determination

ARUP #: 2004464

Methodology: Quantitative Ultrafiltration/Quantitative Enzymatic

Comments:

Guidelines

General

Comprehensive Review: December 2011
Last Update: December 2011

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