Pathology of gastritis and gastric ulceration in the horse. Part 2: a scoring system

High numbers of racehorses in training are reported to have gastric ulceration. Gross lesion scoring systems exist, but there is no fixed protocol with which to record gastric microscopic findings. In man, the histological classification of stomach lesions helps in the identification of recognised and emerging aetiologies of gastric disease and aids accurate comparison of findings between studies. In horses, the development of such a system would therefore be of benefit.

To develop a pathological scoring system that can be applied to examine samples of the equine stomach at biopsy and post mortem.

The equine gastritis grading (EGG) system was developed initially using horse stomachs at post mortem. The protocol involved sampling tissue from 5 fixed locations within the squamous and glandular regions. Histological examination recorded both type and degree of inflammatory infiltrate and the presence of erosions, ulceration or any other reactive change in each slide. These results were combined and an overall diagnosis of gastritis type given for each stomach.

This is the first example of a complete pathological scoring system developed specifically for recording gastric lesions in the horse. It provides a thorough and repeatable method with which to examine the equine stomach in microscopic detail. It can be used in diagnostic or research situations and the consistency of the information gathered will enable accurate comparison of data between different studies. It aims to give an indication as to the currently undetermined pathological variations seen in the stomach of healthy and diseased horses, as well as increasing the understanding of the pathogenesis of gastritis and gastric ulceration. Using this information, interpretation of biopsy samples is improved.