Diagnostic Approach for Duodenitis

Initial Evaluation and Biopsy Protocol

The American Gastroenterological Association recommends that biopsies should be obtained from the duodenum during the EGD when duodenitis is identified to confirm the diagnosis histologically and assess for potential causes 1, 2
Histopathological review should be performed by a gastrointestinal pathologist to determine the presence and severity of inflammation 1
When obtaining biopsies from the duodenum, a minimum of four biopsies from the second part of the duodenum including a specimen from the duodenal bulb should be taken if celiac disease is suspected 3
Testing for H. pylori infection should be performed in all patients with duodenitis, as it is a common cause that requires specific treatment 4

Universal testing for H. pylori should be performed through biopsy-based methods or non-invasive tests 4
If seronegative enteropathy is suspected, HLA typing may be useful to assess for celiac disease 1
A detailed medication history should be obtained to identify potential causative agents 1
Travel history should be assessed for risk factors associated with tropical sprue or parasitic infections like Giardia 1
Assess for symptoms such as fever, bloody diarrhea, and weight loss which might suggest Crohn's disease or lymphoproliferative disorders 1

In cases where gastric cancer is a concern, additional workup should include Chest/abdomen/pelvis CT with oral and IV contrast 4, 5
Testing for microsatellite instability (MSI) by PCR/NGS or mismatch repair (MMR) by immunohistochemistry should be performed 4
Endoscopic ultrasound should be considered if early-stage disease is suspected 4

For patients with duodenitis where an underlying cause was identified and treated, a follow-up EGD with biopsy might not be necessary depending on clinical response 1
For patients with idiopathic duodenitis, consider repeating endoscopy after a period of time to assess for resolution 1
If seronegative celiac disease is suspected, follow-up endoscopy with biopsy should be performed after approximately 12 months on a gluten-free diet to confirm mucosal improvement 1

The presence of duodenitis does not confirm GERD as a cause of extraesophageal symptoms, and additional testing may be needed to establish this connection 6, 7, 8