Use and contribution of chromoendoscopy with lugol, indigo carmine and methylene blue in the upper digestive tract of dogs

Abstract

Chromoendoscopy is defined as the topical application of aqueous dye in the gastrointestinal
tract mucosa. These dyes have the function of showing early or discrete changes which may
go unnoticed in conventional examination. Therefore, this procedure enables altered tissue
collection or monitoring of pre-existing diseases. In Veterinary Medicine, there were no
studies that have used this technique, but there are many conditions in which it can be
employed as research or monitoring of esophagitis (such as humans Barrett's esophagus),
erosive or polypoid gastric lesions and duodenal injuries. In the present study, ten adult dogs
underwent endoscopy (EGD), followed by chromoendoscopy (CRE) and biopsy of
esophagus, stomach (fundus, body and pyloric antrum) and duodenum, when available.
Biopsies were sent for histopathology for identification of presence or absence of lesions in
the collected samples. The aim of this study was to describe the technique of
chromoendoscopy in dogs, evaluate its effectiveness on the identification and delineation of
lesions in the upper digestive tract of dogs and correlate endoscopic findings before and after
application of the technique with histopathologic results. The correlation between EGD and
CRE by histopathology (gold standard) was evaluated using the Kappa test. The results
showed significant agreement in CRE of esophagus with accuracy of 83.33%. Moderate
agreement in conventional endoscopy (CE) of esophagus and CRE of fundus, body and
pyloric antrum were demonstrated with an accuracy of 83.33%, 70%, 70% and 70%
respectively. Fair agreement was found in CRE of stomach, with an accuracy of 70%. There
was poor agreement in EGD of pyloric antrum and EGD and CRE of duodenum, with an
accuracy of 50%, 40% and 40% respectively. There was no correlation between the tests in
the EGD of gastric fundus, gastric body and stomach, with an accuracy of 40%, 40% and
43.33% respectively. CRE is slightly difficult to perform but is effective to guide biopsies of
esophagus and stomach.