What is the most appropriate test to identify the cause of pancreatitis in this patient?

Identifying the Cause of Pancreatitis in a Patient with Severe Hypertriglyceridemia

Serum triglyceride testing is the most appropriate test to identify the cause of pancreatitis in this patient, as the markedly elevated glucose (500 mg/dL) and A1c (10.3%) strongly suggest hypertriglyceridemia-induced pancreatitis. 1, 2

Initial Diagnostic Workup

Based on the patient's clinical presentation, several key factors point toward hypertriglyceridemia as the likely etiology:

• Severely elevated blood glucose (500 mg/dL)
• Markedly elevated A1c (10.3%)
• Obesity (BMI 43)
• Hypertension
• No alcohol use (ruling out alcoholic pancreatitis)

Required Laboratory Tests

According to AGA guidelines, the following tests should be obtained at admission for all patients with suspected pancreatitis 1:

• Serum amylase or lipase (lipase preferred due to higher specificity of 89-94%) 2
• Triglyceride level
• Calcium level
• Liver chemistries (bilirubin, AST, ALT, alkaline phosphatase)

Imaging Studies

• Abdominal ultrasonography should be performed at admission to evaluate for gallstones or biliary obstruction 1
• If the initial ultrasound is negative but suspicion for gallstone pancreatitis remains, repeat ultrasonography after recovery or consider endoscopic ultrasonography (EUS) 1, 2

Diagnostic Algorithm for This Patient

1. First-line testing:

   • Serum triglyceride level (most likely to identify the cause in this patient)
   • Abdominal ultrasound (to rule out gallstone pancreatitis)

2. If triglycerides are elevated (>1000 mg/dL):

   • Diagnosis of hypertriglyceridemia-induced pancreatitis is confirmed
   • No further diagnostic testing for etiology is needed

3. If triglycerides are not markedly elevated:

   • Proceed with liver chemistries to evaluate for gallstone pancreatitis
   • Consider CT or EUS (patient is >40 years old) to evaluate for pancreatic malignancy 1

Management Considerations

• Aggressive fluid resuscitation is essential, especially given the patient's hyponatremia (sodium 120) 2
• Correction of hyperglycemia will be necessary to manage the underlying hypertriglyceridemia
• Monitor renal function closely (BUN already elevated at 25) 3

Common Pitfalls to Avoid

• Don't skip triglyceride testing: Even in the absence of alcohol use, hypertriglyceridemia is a common cause of pancreatitis, especially in patients with uncontrolled diabetes 1, 2
• Don't rely solely on CT scanning: While contrast-enhanced CT is valuable for assessing severity and complications, it should be performed selectively and is not the first-line test for determining etiology 1, 2, 4
• Don't miss electrolyte abnormalities: The patient's hyponatremia (sodium 120) requires urgent correction alongside pancreatitis management 2
• Don't delay treatment: While identifying the cause is important, immediate supportive care with fluid resuscitation and correction of metabolic abnormalities takes priority 1, 2

Severity Assessment

Once the etiology is established, severity assessment should be performed using:

• Clinical assessment
• APACHE II scoring (score >8 indicates severe disease)
• CT Severity Index after 72 hours in severe cases 2

The combination of uncontrolled diabetes, hyponatremia, and elevated BUN suggests this patient may have moderate to severe pancreatitis requiring close monitoring and aggressive management.