Treatment

Medical management is the preferred treatment for gastric impactions. The most important component of medical treatment is enteral administration of fluids. Frequent administration of low volumes of enteral fluids (about 2 L/hour) may help to hydrate and soften the impaction. Isotonic fluids may hydrate the impaction more rapidly than plain water. Intravenous fluids are typically less efficacious than oral fluids at hydrating gastrointestinal impactions but may be a useful part of the initial therapy in dehydrated horses. Laxatives, including dioctyl sodium succinate (10 to 50 mg/kg given in 2 to 4 L water), magnesium sulfate (0.5 to 1 g/kg in 2 to 4 L water every 24 hours), or mineral oil (2 to 4 L, every 12 to 24 hours), have been used in cases of gastric impaction, although the efficacy of these treatments is unknown. Magnesium toxicosis has been reported in horses following administration of magnesium sulfate, so blood magnesium concentration should be monitored in horses receiving multiple doses. Gastric lavage may be attempted but often yields little improvement. If attempted, gastric lavage should be performed by administering small volumes (2 to 4 L) of water and draining multiple times through a nasogastric tube.

Horses with concurrent gastric ulcers may benefit from gastric ulcer treatment. Acid suppressant therapy (omeprazole, 4 mg/kg, PO, every 24 hours; ranitidine, 6.6 mg/kg, PO, every 6 to 8 hours; or ranitidine, 1.5 mg/kg, IV, every 6 hours) is likely the most effective treatment for ulcers, but antacids (aluminum or magnesium hydroxide, 0.5 mL/kg, PO, every 4 to 6 hours) can transiently increase gastric pH. Sucralfate (20 to 40 mg/kg, PO, every 6 hours) may be used in conjunction with acid suppressant therapy; however, sucralfate has not been demonstrated to promote ulcer healing and should not be used as a sole treatment.

Horses may experience discomfort following initial enteral fluid administration because the impaction may expand with hydration. Retrieval of any excess fluid or gastric contents should be attempted through a wide-bore nasogastric tube if signs of colic develop after administration of fluids. Gastric rupture is a possible sequela of gastric impaction, so careful monitoring of clinical signs and judicious use of enteral fluids, particularly early in treatment, are recommended. In humans with gastric persimmon phytobezoars, partial fragmentation of the bezoar (either through endoscopic fragmentation or partial dissolution) has been reported to result in subsequent small intestinal obstruction.

Primary feed (hay) impactions may resolve within a few days. Concretions of expansive feed, such as persimmon impactions, may require weeks or months of medical treatment before resolving. In cases in which long-term treatment is necessary, small, frequent meals of a complete pelleted feed may provide for nutritional needs without adding to the impaction.

In cases of gastric impaction that are nonresponsive to medical treatment, exploratory celiotomy may be necessary to fragment or remove the impaction. Intraoperative administration of fluids through nasogastric tube and concurrent massage of gastric contents or transmural (gastric) injection of fluid and massage of gastric contents may resolve impactions. The advantage to these procedures over gastrotomy is the presumed decreased risk for peritonitis. However, if these treatments fail, a second surgery may be needed to remove the impaction so that an incision is not made into the fluid-filled stomach. Gastrotomy has been performed successfully in the horse but carries a risk for peritonitis. The advantages of gastrotomy include confirmation of impaction resolution and observation of the stomach for signs of injury.