What is a gastroscope?
What is a gastroscope and how does it work?
Gastroscopy is the procedure to view the inside of a horse’s stomach. To do this we pass a gastroscope (camera) into the stomach. A gastroscope is a flexible endoscope, used to visualise the oesophagus, stomach and proximal duodenum (the first part of the small intestines). A gastroscope consists of a long (three metre) flexible insertion tube which is passed into the horse’s stomach, down the oesophagus via the nostril. At the end of the gastroscope is a camera which is used to visualise the stomach. The insertion tube is attached to a hand piece that controls the direction of the scope, and instrument, water and air ports. Later can be used to clear debris from the camera or stomach lining, and air can be used to inflate the stomach, to improve visualisation. The gastroscope is then connected to a light source and a computer screen so we can all see what is present in the stomach and take video recordings or still photographs of any areas of interest.
What is the process?
A gastroscopy needs to be performed by a qualified veterinarian. The equipment can be difficult to transport particulary the computer screen, therefore most gastroscopes are performed at the clinic.
In preparation for a gastroscopy, it is very important that the stomach is empty. The horse needs to be fasted for 12 hours prior to the planned gastroscopy. Ideally, the horse is stabled the evening prior to gastroscopy with all food and hay removed. A grazing muzzle can be used if the horse tends to eat shavings/bedding. Water buckets should be removed the morning of the procedure; four to six hours prior to gastroscopy. The main reason why we want to look into the stomach is to diagnose equine gastric ulcer syndrome (EGUS, see explanation below). Prior to the gastroscopy, one of our vets will usually take a full history and perform a clinical exam before administering a sedative. Sedation is used to ensure the horse is relaxed and comfortable and will stand quietly and calmly for the duration of the procedure.
In addition to the sedative, gastroscopy is normally performed with the horse standing in a crush and with a nose twitch applied. These precautions make the procedure safer for all involved, and enable a full and systematic examination so any problems can be identified.
Most vets will first pass a lubricated nasogastric tube up one nostril and down into the oesophagus. The role of the tube is to protect the endoscope and prevent it from kinking. The gastroscope is then passed down this tube and the vet may then start the recording. It is essential to examine the entire stomach. Once the examination is complete, the gastroscope will be removed first, then the tube. Your horse can go back to their regular diet once they have fully recovered from the sedation.
Equine Gastric Ulcer Syndrome- EGUS
The main reason why we want to look into the stomach is to diagnose equine gastric ulcer syndrome (EGUS). This is a very common condition, with prevalence estimates from 25 to 50 percent in foals and 60 to 90 percent in adult horses, depending on age, performance, and evaluated populations. EGUS is an umbrella term to describe erosive and ulcerative diseases of the stomach and this is further divided into the 3 regions of the stomach; the non-glandular or squamous region and the fundus and pylorus of the glandular region. Approximately 80% of gastric ulcers appear in the upper squamous compartment, as the epithelium here is not well protected against stomach acid. Ulcers are further graded 0-4 depending on their severity.