Stomach Dilation and Rupture in Horses

Gastric dilation is generally caused by a buildup of trapped food, fluid, and/or gasses in the stomach which are not moving through the GI tract normally. The severity of gastric dilation in horses depends on how much buildup has accumulated, how severe the blockage (if one is present), and how prompt veterinary attention is. With proper treatment, gastric dilation is manageable.

Left untreated, gastric dilation can worsen, eventually causing the stomach to rupture. The contents of the stomach flood into the abdominal cavity, contaminating it with partially digested food, bacteria, stomach acid, and other gastric juices. This contamination causes peritonitis (inflammation of the inner abdominal wall) and endotoxic shock (a severe, generalized inflammatory reaction), which are fatal in most cases.

Stomach dilation and rupture is not common in horses. Horses who are showing signs of gastric dilation require emergency veterinary attention so the stomach does not rupture.

Factors that increase the risk of gastric dilation include

• Overeating
• Over-drinking
• Poor chewing
• Eating food that is highly fermentable, such as beet pulp, grains, and lush grass
• Pre-existing proximal enteritis-jejunitis
• Pre-existing right dorsal displacement

Horses’ stomachs have evolved to graze for a large portion of their day and so they are well-suited to many small meals over their waking hours. In horses who eat too quickly or too much, drink too quickly or too much, or eat foods that ferment and produce high quantities of gas or are tough to break down, the stomach is required to hold more than it should, forcing the walls to stretch to accommodate the load. This stretching is called gastric dilation.

In some cases, gastric dilation is the result of issues occurring further along the gastrointestinal tract, which prevent food from moving properly.

If left untreated, these issues cause the stomach to stretch beyond its capacity and the walls tear open. This is called gastric rupture.

When gastric rupture occurs, symptoms appear to suddenly resolve as the pain from stomach stretching is no longer present. As time progresses, peritonitis (inflammation of the abdominal lining) and severe bacterial infections arise. The symptoms of gastric rupture are an emergency and include:

• Severe lethargy
• Rapid, shallow breathing
• Rapid muscle contractions and spasms
• Blue or purple gums and other mucus membranes

In horses with signs of colic, immediate veterinary attention is required to identify the underlying cause. In horses with gastric dilation, it is crucial to detect the cause of the dilation and treat it quickly before the stomach ruptures. Diagnostic tools include:

• Physical examination
• Rectal palpation
• Nasogastric intubation
• Bloodwork
• Ultrasound
• Endoscopy

Note: nasal intubation should only be performed by a veterinarian. There is no safe way to intubate a horse at home. Horses often require sedation for diagnostic examination.

The primary treatment for gastric dilation is repeated deflation of the stomach through a nasogastric tube. In some cases, a nasogastric tube is permanently placed. While repeated deflation is occurring, treatment focuses on treating the underlying cause of the gastric dilation. Possible treatments include:

• Pain medication
• IV fluids
• Oral fluids
• Oral medications to soften and resolve any impactions
• Medications to protect the gastrointestinal lining
• Surgical intervention

If treated promptly and managed properly, the prognosis for gastric dilation is excellent. Gastric rupture is almost invariably fatal, even with prompt surgical intervention.

Preventative strategies for gastric dilation include:

• Adjusting feeds to avoid fermentable feeds
• Feeding smaller meals more often
• Stimulating proper chewing by double netting hay or changing to a more palatable ration
• Routine dental care
• Routine deworming based on veterinary recommendation

Gastric dilation is uncommon in horses. Gastric rupture is rare.

• Deflation of stomach with nasogastric tube
• IV fluids
• Oral fluids
• Pain medication