 [ Symptoms ] what is duodenitis [ Disease ] duodenitis is inflammation of the duodenum the first portion of the small intestine the duodenum is a tube around a foot long its near end connects to the stomach the duodenum is far end blends into the rest of the small intestine duodenitis can only be diagnosed with a tissue biopsy which is performed using endoscopy esophagogastroduodenoscopy the duodenum can become inflamed irritated swollen and occupied by white blood cells for various reasons the most common is infection by h pylori a bacteria that lives in the stomach andor duodenum about half of americans over age 60 have been infected with h pylori at some point in life h pylori stimulates increased acid production by the stomach and causes low grade inflammation of the duodenum duodenitis symptoms can include pain in the middle of the belly or indigestion in some cases the inflammation of duodenitis worsens to create a small sore ulcer in the duodenum is wall less commonly inflammatory conditions can cause duodenitis crohn is disease ulcerative colitis whipple is disease severe stress caused by surgery or a serious infection sepsis cases of duodenitis or duodenal ulcer caused by h pylori can usually be cured with antibiotics and stomach acid suppressing drugs