From the AGA Journals

Experts refine nomenclature for eosinophilic GI disorders

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Working toward personalized care

Eosinophilic conditions of the gastrointestinal tract have risen in incidence leading to significant patient symptom and morbidity, but thankfully there have been tremendous innovations in identification, management, treatment, and drug development. In this excellent article, an international consensus was created to reflect these rapidly changing understanding of the phenotypes with updated diagnostic nomenclature.

Rishi D. Naik, MD, MSCI, is an assistant professor, department of medicine, section of gastroenterology & hepatology, Esophageal Center at Vanderbilt University Medical Center.

Dr. Rishi D. Naik

Eosinophilic esophagitis (by far the common eosinophilic GI condition) remains unchanged in its nomenclature, but the prior use of eosinophilic gastroenteritis should no longer be used. Instead, the organ involved – for example, stomach, small bowel, or colon – should be identified, as eosinophilic gastritis, eosinophilic enteritis, or eosinophilic colitis, respectively. This does reflect clinical and patient practice on where biopsies can be routine obtained from when patients have symptoms. Debates are still ongoing on how to define overlapping sites (for example, simultaneous esophagus and stomach involvement) or if duodenal, jejunal, and ileum eosinophilic conditions should be separated. This new framework will allow us to begin settling these debates based on patient outcomes.

Redefinition of these conditions will help in many aspects. First, advances in therapy targeted as eosinophilic trafficking have been approved with many biologic therapies in the pipeline and understanding their treatment effects and targets will help our patients. Second, improved nomenclature will help better understand the genetic, phenotypic, and therapeutic options for these conditions providing our patients with personalized care. As the understanding of eosinophilic conditions expands with the growth of genetic associations and drug therapies, we are matching our inflammatory bowel disease colleagues in their successes to provide our patients with personalized care.

Rishi D. Naik, MD, MSCI, is an assistant professor, department of medicine, section of gastroenterology & hepatology, Esophageal Center at Vanderbilt University Medical Center, Nashville, Tenn.


 

FROM CLINICAL GASTROENTEROLOGY AND HEPATOLOGY

A new international consensus paper is recommending that eosinophilic GI diseases (EGIDs) should be named according to more specific criteria. The paper seeks to update nomenclature to improve research and bolster clinical clarity.

The involved part of the GI tract should be specifically named, and the abbreviation “Eo” should be used. Furthermore, the umbrella term should be EGID instead of the currently used “eosinophilic gastroenteritis,” according to the statement published in Clinical Gastroenterology and Hepatology. The statement included 91 authors from five continents who filled out two rounds of surveys. In total, 93% completed the first and 90% completed the second. The paper produced 22 statements, with a consensus reached on all but 2.

EGIDs are chronic, immune-driven disorders that produce gastrointestinal symptoms and are characterized by eosinophil-dominant inflammation in specific GI regions. Although eosinophilic esophagitis (EoE) is the most well known of these conditions, other EGIDs have become more commonly recognized in recent years and are the subject of intense study. Other affected areas include the stomach, small bowel, and colon, where it can occur individually or in combination.

Efforts are underway to develop guidelines for diagnosis and treatment of EGIDs, but there was initial confusion surrounding the term eosinophilic gastroenteritis since its definition varied significantly in different clinical and research settings, according to the authors. That term varyingly referred to stomach alone, small bowel alone, stomach and small bowel, or any region of the GI tract.

“This nonstandardized use of nomenclature highlighted a need for a common language for non-EoE eosinophilic GI disease names, not only for clinical practice, but also for the consistent data collection required for research to continue to advance the field,” co–first authors Evan S. Dellon, MD, MPH, AGAF, from the University of North Carolina at Chapel Hill, and Nirmala Gonsalves, MD, from Northwestern University, Chicago, and colleagues wrote. “This step, while seemingly rudimentary, was essential to inform the guideline efforts that are now underway.”

After responses to the surveys were analyzed, respondents participated in one of two scheduled meetings held on a video conferencing platform in May 2021. Feedback from these meetings was then used to create a second round of 29 statements which were again distributed, and participants were asked to either agree or disagree with each statement. Agreement was set a priori at 70%. In all, 38% of the participants were women, and 91% worked in academic or university settings.

In routine clinical practice, conditions with eosinophil-dominant inflammation in the absence of secondary causes outside of the esophagus can collectively be referred to clinically as non-EoE EGID. Stomach involvement should be called eosinophilic gastritis (EoG), small bowel involvement eosinophilic enteritis (EoN), and colon involvement eosinophilic colitis (EoC).

For research use, and clinical use if desired, the authors called for greater granularity in description of the conditions, with each location named. For example, if the stomach and small bowel are both involved, the condition should be termed eosinophilic gastritis and enteritis. The authors could not reach a consensus for terminology when the esophagus is also involved, leading to the recommendation that it can be included using the phrase “with esophageal involvement” or by using EoE, although they note that this could be confusing since EoE is the current term for eosinophilia isolated in the esophagus.

The authors came to universal agreement in many areas, but there were exceptions that mostly centered on how to name conditions that affect multiple areas of the GI tract. It remains uncertain whether eosinophilia in different regions is caused by the same pathogenesis. Some experts felt that a “primary” location of EGID should be identified using predominant symptoms, endoscopic features, and complications. However, the authors anticipate that this nomenclature will change over time.

The authors noted that the clinical manifestation of the disease should remain the driving factor behind classification. Testing should be driven by clinically relevant questions and overtesting should be avoided. More details on this are likely to be forthcoming in future guidelines.

The consensus statement is limited by the fact that most participants were from academic settings. These recommendations do not apply to eosinophilic disorders of gallbladder, liver, or pancreas. Application of the recommendations to the small bowel may be too general or specific, but are meant primarily as a starting point for further refinement.

These limitations should help to drive further research. For example, molecular and pathogenic data could help distinguish EoE from “esophageal involvement” by determining if pathogenic mechanisms are the same or different, which would in turn lead to lumping the conditions into a single term or keeping them separate.

“The iterative and collaborative process led to agreement on nearly all aspects of the proposed nomenclature framework, and has identified future research directions. It is expected that as more data are collected, the nomenclature will again be updated to reflect best practices and the underlying pathogenesis of these disorders,” the authors concluded.

The authors disclosed relationships with various industry companies, include AstraZeneca, Celgene, GlaxoSmithKline, Regeneron, Sanofi, and Takeda.

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Updates in eosinophilic gastrointestinal diseases