Role of advanced diagnostics for eosinophilic esophagitis

In eosinophilic esophagitis (EoE), diagnostic tests aid in the identification of pathophysiologic consequences and accurate detection of the disease. The EoE Endoscopic Reference Score (EREFS) classifies and grades the severity of the five major endoscopically identified esophageal features of EoE (edema, rings, exudates, furrows and strictures). The EREFS may be useful in the evaluation of disease severity and as an objective outcome of response to therapy. pH monitoring identifies the presence of abnormal degrees of acid exposure in the esophagus that characterizes gastroesophageal reflux disease. The presence of acid reflux, however, does not indicate that the reflux is responsible for esophageal eosinophilia. Esophageal manometry has not demonstrated a characteristic abnormality with sufficient sensitivity to make the test of diagnostic value in clinical practice. On the other hand, manometric characteristics of esophageal pressurization and longitudinal muscle dysfunction may help identify important pathophysiologic consequences of EoE. Esophageal impedance testing has demonstrated increased baseline mucosal impedance that correlates with increased epithelial permeability in EoE. Reduced mucosal integrity may provide intraluminal allergens access to antigen-presenting cells, serving as an early event in the pathogenesis of EoE. The functional luminal impedance probe (FLIP) provides quantitative assessment of esophageal mural compliance, a physiologic correlate of remodeling in EoE. Studies using FLIP have associated reductions in esophageal distensibility in EoE with the important outcome of food impaction risk. Finally, confocal endomicroscopy, multiphoton fluorescence microscopy and novel eosinophil-enhancing contrast agents are emerging methods that may allow for in vivo visualization of esophageal eosinophilic inflammation, thereby improving the detection and understanding of this emerging disease.