Gastrointestinal medicine

Horses referred to the R(D)SVS for the investigation of gastrointestinal (GI) disease constitute the majority of cases attended by the Medicine Service.

These vary from emergency colic referrals to chronic diarrhea and weight loss investigations. This consistently high caseload over the years has resulted in the Medicine Service team accruing a vast amount of clinical experience in this field and an extensive publication record in the veterinary clinical and scientific literature.

The clinical presentation of GI cases largely determines the route of diagnostic investigation. Acute abdominal pain (colic) referrals are received regularly both within and out- with normal working hours and their initial assessment is aimed at determining the need for surgical intervention. With such cases, there is close liaison with other services, including surgery and anaesthesia. Diarrhoea cases vary in their severity, with some requiring emergency clinical stabilisation and others warranting a more exhaustive diagnostic approach. Weight loss can be the most apparent clinical consequence of a vast array of diseases, both GI and non-GI in origin. Consequently, our approach to these cases can be extensive, involving the clinical assessment of many body systems.

Diagnostic techniques

The GI medicine service offers a full range of diagnostic techniques.

General

The diagnostic investigation of many GI cases will require the use of a variety of routinely applied diagnostic techniques, including rectal examinations, passage of a stomach tube, collection and analysis of abdominal fluid and blood analysis. However, there are more specialised techniques which are commonly used in these cases, including gastroscopy, ultrasonography and rectal biopsy.

Gastroscopy

Gastric ulceration is an increasingly recognised condition in horses which has been linked to a variety of clinical presentations, including poor performance, decreased appetite, failure to gain weight and colic. Our 3 metre gastroscope allows us to fully evaluate the horse’s stomach and we routinely receive referrals on an out-patient basis solely for gastroscopic examination. In addition, gastroscopy constitutes part of our more extensive investigation of other cases, including weight loss cases, grass sickness and oesophageal obstructions.

Ultrasonography

Abdominal ultrasonography is regularly used in our investigation of most GI cases and the Medicine Service staff are all highly proficient in the use of this diagnostic technique. It is employed, both as a rapid and effective tool in the assessment of acute colic cases and as an invaluable and sensitive means of assessing intestinal contents, wall thickness and motility in cases of diarrhoea and weight loss.

Video: Annotated movie clip of an ultrasound examination of the lower left abdomen of a horse with fibrin deposition and adhesions between the spleen and liver.

Rectal biopsy

The collection and analysis of rectal biopsies is generally restricted to cases of chronic diarrhoea and weight loss; we can look at cellular changes within the intestines at  less accessible sites, access to which would normally require surgery.  Although not highly sensitive, this technique can offer very valuable diagnostic information and inform the most appropriate therapeutic approach. Staff within the Medicine Service have also assessed the value of this technique in the diagnostic approach to Equine Grass Sickness.