Gastric Impaction

What is a gastric impaction?

A gastric impaction is a firm accumulation of food in a horse’s stomach. It develops over time and can cause the stomach to become enlarged, and in some cases, lead to rupture of the stomach.

Why do horses get them?

Most of the time, gastric impactions just occur without an underlying cause ever being identified. However, they can sometimes be caused by the accidental consumption of dry feed such as sugar beet, which absorbs liquid in the stomach and swells. Gastric impactions can also occur gradually in horses whom have lost multiple teeth and may swallow long strands of fibre without chewing them properly. Conditions such as peritonitis (infection of the lining of the abdomen) can reduce the muscle contractions responsible for squeezing food through the body, and it is thought that this can lead to the development of impactions in some cases. Rarely, cancerous masses can obstruct the outflow tract of the stomach, causing food to build up inside it.

What signs might a horse with a gastric impaction show?

This depends on how quickly the gastric impaction has formed, and how large it is. If the impaction has reached an advanced stage, the horse may show moderate to severe colic signs. In cases where the impaction has developed gradually, signs can include reduced appetite and weight loss; the horse would usually produce less droppings than normal.

How does the vet diagnose a gastric impaction?

Gastric impactions can be diagnosed by performing a gastroscope (passing a camera into the horse’s stomach) after they have been starved for 16-24hours. Gastric impactions can sometimes also be seen by scanning the abdomen with an ultrasound machine. In cases where the horse is colicking, the gastric impaction may be diagnosed at surgery.

How are gastric impactions treated?

Treatment involves passing a tube down into the stomach and lavaging it with water. The aim of this is to soften and break down the impaction, and retrieve the food material by siphoning it back out through the tube. This may need to be repeated many times before the impaction is cleared. Sometimes carbonated drinks, such as diet coca cola, are administered via the tube to help break down the impaction. Horses will also receive pain relief, and intravenous fluids and nutrients if they are unable to eat or drink during treatment. Gastric impactions are best managed in a hospital setting.

What is the long term outlook for a horse whom has suffered a gastric impaction?

This depends on whether or not an underlying cause is identified, and if so whether that cause is treatable. If an obstruction to the outflow tract of the stomach is identified, or the impaction occurs again when the horse is re-fed, the prognosis is poor. Some horses can be managed successfully on grass and pellet-based diets. It is important that all horses receive regular dental examinations, and that signs such as reduced appetite or reduced number of droppings are bought to the attention of your vet.