Gastric impactions are often diagnosed when horses are ‘gastroscoped’ as a check for ulcers. The reality is that nearly all of these are not true impactions, but rather unexpected retention of feed in stomach after fasting. The normal stomach will form firm, round boluses as the feed is moved into and out of the antrum. A horse with a gastric impaction will have feed at the gastro-oesophageal opening, often preventing entry of the endoscope into the stomach.
True primary gastric impactions are uncommon.
Primary gastric dilation/impaction is often seen after rapid grain engorgement, particularly in stallions. There are several causes of gastric rupture in horses, with most cases occurring in response to fluid accumulation secondary to small intestinal obstruction, strangulating or otherwise. Gastric impaction is another cause of gastric rupture.
Risk factors for gastric impaction include rapid over-eating, ingestion of very coarse roughage (e.g, bedding), ingestion of foreign material, poor dentition, or consumption of feeds that swell after consumption. The latter includes persimmon seeds, mesquite beans, psyllium products, and sugar beet pulp preparations (e.g., Speedi-Beet).
Ingestion of ripe persimmons is reasonably common and access should be avoided. Ingestion occurs in late autumn and winter in regions where persimmons (Diospyros virginiana) grow.
Signs and diagnosis
The clinical signs are highly variable. Colic may be present suddenly or may be insidious. The severity of colic also can range from mild (recumbency) through to severe. In all cases there is refusal of feed, and in some chronic cases there may be rapid weight loss.
The diagnosis can be challenging. Any horses with moderate to severe pain where reflux is expected, but not obtained should evoke suspicion. Ultrasound confirms enlargement of the stomach, again if reflux is not obtained then ideally endoscopy should be performed.
Therapy
Medical therapy can include analgesics, intravenous fluid therapy, and the administration of diet, caffeine-free cola. Therapy may include surgery, an exploratory laparotomy with an incision into the stomach (gastrotomy) and removal of contents. Although this sounds straightforward, it is not. The stomach lies deep under the ribcage and spillage of contents is a common complication. A J-incision was recently described to improve surgical access to the stomach.
Tags: Gastrointestinal diseases