Gastric Dilation and Rupture - Horse

Also known as:

Gastric Rupture

Description

Gastric dilation in the horse may be primary, secondary or idiopathic.(Sanchez)

Aetiology

Primary causes: gastric impaction, food engorgement, excessive water intake after exercise, aerophagia and parasitism(141,146). Excessive consumption of fermentable feeds (grains, lush grass, and beet pulp) causes a large increase in the production of volatile fatty acids which is thought to delay gastric emptying.(Merck)
Secondary causes: primary intestinal ileus or small or large intestinal obstruction. Dilation resulting from small intestinal obstruction is the most common cause. Fluid from the obstructed small intestine accumulates in the stomach, causing naso-gastric reflux. Gastric dilation may also occur with certain colonic displacements, especially right dorsal displacement of the colon around the caecum. It is hypothesised that the displaced colon obstructs duodenal outflow. Gastric fluid accumulation is also characteristic of proximal enteritis-jejunitis.(Merck)

  If untreated, gastric dilatation associated with overeating can rapidly lead to gastric rupture.

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)

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.

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

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.