Gastric Dilation and Rupture - Horse

Also known as:

Gastric Rupture

Description

Aetiology

The most common cause of gastric dilatation in horses is excessive gas or intestinal obstruction. Gastric dilatation may be associated with overeating fermentable feedstuffs such as grains, lush grass, and beet pulp. Presumably the large increase in production of volatile fatty acids inhibits gastric emptying. If untreated, gastric dilatation associated with overeating can rapidly lead to gastric rupture. If intestinal obstruction is the cause, the obstruction most often involves the small intestine. The fluid from the obstructed small intestine accumulates in the lumen of the stomach, causing dilatation of the stomach and retrieval of gastric reflux on passage of the nasogastric tube. Gastric dilatation also may develop in some horses with certain colonic displacements, most notably right dorsal displacement of the colon around the cecum. It is presumed that the displaced colon obstructs duodenal outflow. Gastric dilatation with fluid also is a characteristic of proximal enteritis-jejunitis. Rupture of the stomach is a fatal complication of gastric dilatation. The stomach generally tears along its greater curvature. About two-thirds of all gastric ruptures occur secondary to mechanical obstruction, ileus, and trauma; the remaining cases are due to overload or to idiopathic causes. (Merck)

Dilation is primary, secondary or idiopathic. Causes of primary: gastric impaction, grain engorgement, excessive water intake after exercise, aerophagia and parasitism(141, 146). Secondary more common and can result from primary intestinal ileus or small or large intestinal obstruction.

Clinical signs

Gastric dilation usually produces:

Acute, severe colic
Tachycardia
Pale mucous membranes
Retching(Merck)
Gastric reflux (time to development is proportional to the distance to the intestinal segment involved, e.g. 4 hours with duodenal obstruction(147).
Ingesta appears at the nares in severe cases

Gastric rupture typically results in:

Relief
Depression

The inevitable peritonitis and shock will lead to:

Tachypnoea
Tachycardia
Sweating
Muscle fasciculations
Signs of endotoxaemia

Diagnosis

Laboratory findings(141):

Haemoconcentration
Hypokalaemia
Hypochloraemia

Aetiology of gastric rupture

Secondary to small intestinal obstruction
Primary gastric dilation
Idiopathic gastric dilation

Risk factors for gastric rupture(146, 148)

Feeding grass hay
Not feeding grain
Gelding
Non-automatic water source

Nasogastric intubation does not preclude the possibility of gastric rupture, and the amount of reflux obtained before rupture is highly variable(146) Usually occurs along the greater curvature. In horse with rupture due to gastric dilation, the seromuscualris likely wekaens and tears before the mucosa(146,148). In rupture secondary to gastric ulceration, there is usally full-thicknees tearing of equal size in all layers.

Treatment

Surgical repair has been reported for partial thickness tears(149) and one case of a full thickness repair(150).

Prognosis

The prognosis for survival may be excellent in most cases of gastric dilation(MErck) but gastric rupture is usually fatal because of widespread contamination of the peritoneal cavity, septic peritonitis, and septic shock. Food Engorgement: also carries the risk of secondary laminitis.