The Characteristics of Isolated Bulb Celiac Disease in Children

Objectives: Mucosal injury in celiac disease (CD) patients can be patchy, and up to 12% of CD patients can have mucosal changes limited to the duodenal bulb. Hence, recent guidelines recommend obtaining bulb biopsies in addition to distal duodenum. This study aimed to describe a cohort of children with isolated bulb CD and assess the benefit of separating bulb biopsies. Methods: A retrospective chart review between January 2011 and January 2022 at 2 medical centers was conducted. We included children with CD who underwent endoscopy with separated biopsies from the bulb and distal duodenum. A blinded pathologist performed Marsh‐Oberhuber grading on selected cases. Results: We identified 224 CD patients, of which 33 (15%) had histologically confirmed isolated bulb CD. Patients with isolated bulb CD were older at diagnosis (10 vs 8 years; P = 0.03). Median anti‐tissue transglutaminase immunoglobulin A (TTG IgA) level was lower in isolate bulb CD (2.8 vs 16.7 times the upper limit of normal [ULN], P < 0.001). Almost 88% (29/33) of isolated bulb CD patients had an anti‐TTG IgA value of less than 10 times the ULN. Time to anti‐TTG IgA normalization (mean 14 months) was similar between the 2 groups. A pathologist review of diagnostic biopsies could not distinguish between the bulb and distal duodenum biopsies in approximately one‐third of the reviewed samples. Conclusions: Separating bulb from distal duodenum biopsies can be considered during CD diagnosis, particularly in children with anti‐TTG IgA levels less than 10 times the ULN. Larger prospective cohorts are needed to decide whether isolated bulb CD is a unique cohort or an early stage of the conventional CD.