Abstract
Phlegmonous duodenitis is an extremely rare condition, and only a few cases have been previously reported. Here, we report a case of phlegmonous duodenitis caused by Streptococcus parasanguinis and Escherichia coli in a 78-year-old immunocompromised patient with diabetes mellitus and immunosuppressive drugs. Abdominal computed tomography showed diffuse thickening of the duodenum and gastric antrum, and esophagogastroduodenoscopy revealed some erosions with purulent discharge and reddish and edematous mucosa in the duodenal bulb. A bacteriological culture test detected the two abovementioned bacteria and established the diagnosis of phlegmonous duodenitis. Following the initiation of antibiotic treatment, his condition rapidly improved. Endoscopists should be aware of this rare entity and pay attention to the endoscopic duodenal findings similar to those of phlegmonous gastritis, particularly in immunocompromised patients who develop abdominal symptoms with severe inflammation.