Hyperamylasemia

Background

• Amylase is secreted by the pancreas into the duodenum where it aids the catabolism of carbohydrates to simple sugars
• Damage to the pancreas or obstruction to the pancreatic duct causes the enzyme to enter the bloodstream.

Clinical Features

• Pain in the middle of the chest that radiates to the back
• Fever
• Loss of appetite
• Nausea
• Vomiting
• Sweating
• Weakness
• Jaundice
• Rapid pulse
• Steatorrhea

Differential Diagnosis

• Pancreatic:
  • Acute pancreatitis
  • Chronic pancreatitis (can have normal or mildly elevated levels)
  • Pancreatic pseudocyst
  • Pancreatic duct obstruction
  • Pancreatic trauma or neoplasm
• Non-Pancreatic:
  • Salivary gland disease (e.g., parotitis)
  • Perforated peptic ulcer
  • Bowel obstruction or infarction
  • Cholecystitis
  • Ectopic pregnancy
  • Ruptured aortic aneurysm
  • Macroamylasemia
  • Renal failure (impaired clearance)

Evaluation

Workup

• Serum amylase and lipase (lipase is more specific for pancreatitis)
• CBC, CMP (assess electrolytes, renal function, LFTs)
• Liver enzymes, bilirubin, alkaline phosphatase
• CRP (to assess inflammation)
• Abdominal ultrasound (to evaluate gallstones, ductal dilation)
• CT abdomen with contrast (gold standard if pancreatitis is suspected)
• Pregnancy test in females of childbearing age
• Urinalysis (to evaluate renal excretion and exclude other causes)

Diagnosis

• Hyperamylasemia is typically defined as serum amylase >100 U/dL, although labs may vary by reference range.
• Levels >3x normal are suggestive of acute pancreatitis when correlated with clinical presentation.
• Isolated hyperamylasemia without supportive clinical features does not confirm pancreatitis and warrants evaluation for alternative causes.