The correct answer is:

Immunoglobulin (Ig) G4 level

Educational Objective:

Evaluate patients with suspected type 1 autoimmune pancreatitis.

Key Point:

Type 1 autoimmune pancreatitis is distinguished by an elevated IgG4 level.

Explanation:

This patient likely has type 1 autoimmune pancreatitis, which is seen more commonly in men who are middle aged or older. The most common presentation is painless obstructive jaundice due to obstruction of the intrapancreatic bile duct. Less commonly, however, patients can have episodes of acute pancreatitis. Other symptoms include weight loss, vomiting, and glucose intolerance.

Imaging studies show diffuse or local pancreatic enlargement. CT often shows a diffusely enlarged, sausage-shaped pancreas in which enhancement with the intravenous contrast agent is delayed and then prolonged.

Most patients have an elevated IgG4 level in serum with positive staining of involved tissues. CRP, amylase, lipase, and triglyceride levels would not help make the diagnosis of autoimmune pancreatitis.

References:

Forsmark CE. Chronic pancreatitis. In: Feldman M, et al. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease. 10th ed., 2016:994-1026.e10.

Madhani D, Farrell JJ. Autoimmune pancreatitis. Gastroenterol Clin North Am. 2016;45:29-