A 25-year-old man comes to the physician for a follow-up appointment. A barium enema is shown. Laboratory studies show elevated p-ANCA. Which of the following additional findings is most likely to be seen in this patient?
Decreased stool pH
Increased stool lipid and protein content
Macrophages in the lamina propria
Non-caseating granulomas in muscularis propria
Urinary bilirubin excess