A 45-year-old woman presents to the emergency department 5 hours after a sudden onset of severe constant epigastric pain that radiates straight through to the back. Past medical history is significant for alcohol use disorder and hyperlipidemia. Family history includes hypertension in her father and breast cancer in her mother. She reports drinking 7-9 beers every day for the past 6 years and smoking 1 pack per day since age 20. She reports nausea and vomiting but denies hematemesis, diarrhea, melena, chest pain, or shortness of breath. She was prescribed atorvastatin in the past but reports not refilling her prescription in several months. Vital signs are temperature 38.3°C (101.0°F), pulse 108 beats/min, respirations 20/min, and blood pressure 148/82 mmHg. Physical examination reveals a non-distended abdomen with upper abdominal tenderness and guarding, no organomegaly, a negative Murphy sign, and no skin abnormalities.
Which of the following laboratory tests is most likely to confirm her diagnosis?
- A) Alkaline phosphatase
- B) Amylase
- C) Aspartate transaminase : Alanine transaminase (AST:ALT) ratio
- D) High-sensitivity troponin
- E) Lipase
This patient has acute pancreatitis with a classic “sudden onset of severe epigastric pain that radiates straight to the back.” While the initial laboratory work-up would include several tests, a lipase elevated 3 times over the upper limit of normal is 96% sensitive and 99% specific for a diagnosis of acute pancreatitis.
Answer choice A: Alkaline phosphatase, is incorrect. Alkaline phosphatase is useful in the evaluation of biliary obstruction. While included on the differential for this patient with epigastric pain, it is less likely with a negative Murphy sign and would not aid in confirmation of the suspected pancreatitis.
Answer choice B: Amylase, is incorrect. Amylase elevation to 3 times the upper limit of normal has a 95% specificity for pancreatitis but only a 61% specificity. In conjunction with lipase, it is commonly used to confirm the diagnosis. However, isolated hyperamylasemia has several etiologies and on its own would not aid in the diagnosis of acute pancreatitis.
Answer choice C: Aspartate transaminase : Alanine transaminase (AST:ALT) ratio, is incorrect. AST:ALT ratio is useful in the evaluation of hepatitis. AST:ALT ≥ 2:1 would suggest alcoholic hepatitis in this patient with alcohol abuse disorder. However, it is less likely given no signs of jaundice, hepatomegaly, or ascites.
Answer choice D: High-sensitivity troponin, is incorrect. Troponin is a marker of myocardial injury and therefore useful in the evaluation and treatment of myocardial infarction (MI). While a significant proportion of MIs in women present atypically, this patient would likely receive an electrocardiogram (ECG) to rule out a cardiovascular etiology of her pain.
Key Learning Point
Lipase elevation ≥3 times the upper limit of normal is laboratory confirmation of acute pancreatitis.
Dr. Raj Dasgupta