Changes

==Description==

==Description==

==Aetiology==

==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)

*'''Primary causes:''' [[Gastric Impaction - Horse|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 [[Colic Diagnosis - Naso-gastric Intubation|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)

   

   

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.   

Aetiology of gastric rupture

'''Risk factors for gastric rupture(146, 148)'''

*Not feeding grain

*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==

==Clinical signs==

'''Gastric dilation''' usually produces:

'''Gastric dilation''' usually produces: