Colitis uncovered
THE term colitis literally means inflammation of the large colon. Because the large colon in a horse is such a large part of its body, this has significant systemic consequences in affected horses. It can be accompanied by inflammation of the small intestine, in a condition known as enteritis, or inflammation of the caecum – a part of the large intestine that is blind-ending like a cul-de-sac – which is known as typhlitis. Given the significant inflammation present, expected clinical signs can be predicted to include fever and thickening of the large colon wall.
When the large colon is inflamed it can’t perform its normal functions, which include absorbing water as ingesta (food and drink) passes through the gastrointestinal tract, leading to diarrhoea. The colon mucosa (the inner lining of the intestinal tract) becomes less effective as a barrier and protein can then leak out from the bloodstream into the diarrhoea. This also allows normal gut flora or diarrhoea-causing pathogens to translocate, or escape, into the bloodstream.
WHAT ARE THE CLINICAL SIGNS?
THERE are three main signs that are frequently linked with colitis. These
