The Pancreas

Question 1

Amylase

• Types
• Associated diseases with elevated amylase
• sensitivity and specificity for acute pancreatitis
• non acute pancreatitis causes of elevated amylase

Answer 1

• Isoenzymes
  
  • Salivary (S type)
  • Pancreatic (P type)
• Uncomplicated acute pancreatitis
  
  • Amylase rises within 2-24 hours and returns to normal in 2-3 days
  • Up to 10% of cases are associated with normal levels of amylase
• Persistence of elevation beyond 5 days suggests a complication such as a pseudocyst
• Higher amylase does not correlate with greater severity but is more specific for pancreatitis
• Sensitivity lowest in chronic relapsing and alcoholic pancreatitis
• Up to 30% of amylase elevations are caused by nonpancreatic disorders:
  
  1. Diabetic ketoacidosis
  2. Peptic ulcer disease
  3. Acute cholecystitis
  4. Ectopic pregnancy
  5. Salpingitis
  6. Bowel ischemia
  7. Intestinal obstruction
  8. Macroamylasemia
  9. Renal insufficiency

Question 2

Lipase

Answer 2

• More specific than amylase but remains elevated for up to 14 days
• Less dependent than amylase on renal clearance

Question 3

Lab cutoffs for amylase and lipase

Answer 3

Amylase

• cutoff of 3x the ULN
• Specificity 95%
• Sensitivity 60-80%

Lipase

• cutoff of 3x the ULN
• Specificity 90%
• Sensitivity 90%

Question 4

Prognosis of acute pancreatitis

Answer 4

Question 5

Etiology of acute pancreatitis (additional tests to order)

Answer 5

• triglycerides
• calcium
• viral serology titers
  
  • mumps
  • coxsackievirus
  • CMV
  • VZV
  • HSV
  • Hepatitis B viruses
  • HIV
• IgG4 levels

Question 6

Tests of pancreatic exocrine function

Answer 6

• Secretin-CCK test
  
  • endoscopic collection of exocrine products after CCK is adminstered intravenously
• Noninvasive tests
  
  • 72 hour fecal fat quantitation
    
    • high fat diet for 6 days (3 days before collection and 3 days during collection)
    • in exocrine deficiency fecal fat exceeds 20 g/day
  • Spot fecal fat
    
    • Sudan black staining of a random stool sample
    • Positive when there are >6 droplets of fat per HPF
  • Stool elastase 1 and stool chymotrypsin decreased in pancreatic insufficiency

Question 7

Answer 7