Difference between revisions of "Gastric Impaction - Horse"
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Revision as of 12:10, 9 August 2010
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This article is still under construction. |
| Also known as: | Colic Impaction |
| See also: | Colic, Gastric Causes |
Description
Gastric impaction is rare in the horse.[1] It can occur spontaneously as a primary condition but is often secondary to other disturbances in the intestinal tract of the stomach such as ulceration or fibrosis at the pylorus.[2] The condition typically causes mild to moderate colic that does not resolve with routine medical treatment.[3]
Aetiology
The specific cause of the impaction is not always apparent[4] but the obstruction typically consists of excessive dry, coarse ingesta such as straw bedding or poor quality forage.[4] It may also be composed of foreign bodies, ingested materials that form a mass (such as persimmon seeds or mesquite beans[5][6][7]) or feeds that tend to swell after ingestion. Gastric impaction may be the result of a gastric atony or defective secretion.[8]
Predisposing factors
- Ingestion of certain feedstuffs including sugar beet pulp, bran, straw, wheat and barley. Beet pulp and bran can become dessicated within the stomach and may not become rehydrated by water or gastric secretions.[2]
- Dental disorders - roughage may be only partially masticated.[2]
- Feeding a horse that has signs of colic - there may be poor gastric emptying associated with generalised decreased gastrointestinal motility
- Rapid consumption of feedstuffs.[4]
- Inadequate water consumption.[4]
- Secondary gastric impaction has been related to ragwort poisoning[9]
Clinical signs
The colic associated with gastric impaction varies from mild and chronic to acute and severe.[3] Other signs reported include:
- Anorexia
- Lethargy
- Prolonged recumbency
- Dysphagia
- Dropping of feed
- Bruxism
- Salivation[8]
- Insidious weight loss (if chronic)[8]
- Spontaenous reflux with gastric contents visible at the nares (in severe cases)[4]
In mild cases where signs resolve spontaneously or with analgesics, owners my continue to feed the horse, which only serves to worsen the impaction.[2]
Diagnosis
- Gastric impaction is suspected if a nasogastric tube cannot be passed or if poorly macerated or digested feed material is recovered from the tube when the horse has been starved for several hours. With gastric distension, the gastoroesophageal junction can become distorted making it difficult to pass the tube.[2]
- On rectal examination, the spleen may be displaced caudally and medially (but this is not specific for gastric impaction).[2]
- Endoscopy would be indicated in a chronic case[3] and may show a full stomach after a fast of 18-24hrs.[4] However it is not diagnostic for impaction as it is difficult to assess gastric distension by endoscopy.[2]
- In a small horse or pony, a lateral radiograph of the cranial abdomen may show the diaphragm displaced cranially
- Ultrasonography may reveal a markedly enlarged gastric echo extending over six or more intercostal spaces on the left side of the abdomen. A marked increase in the thickness of the wall of the stomach may also be imaged.[8]
However, if the horse suffers from acute severe colic, a diagnosis is often made at surgery.
Treatment
If gastric impaction is suspected, the horse should be transported with a nasogastric tube in place to a clinic with surgical facilities.[2] Medical treatment might include gastric lavage with water[3] to remove as much impacted ingesta as possible, which may take several attempts. 100-200ml of an 8% solution of dioctyl sodium sulfosuccinate (DSS) may help to hydrate the dessicated material. IV fluid therapy and analgesia should be commenced, although IV fluids are unlikely to resolve the impaction.[2] Owing to the risk of gastric rupture, gastric motility stimulants should be avoided if the extent of the impaction is undetermined.[2] At surgery the following should be performed:
- In dorsal recumbency, the impacted stomach can be felt extending back midway between the xiphisternum and the umbilicus, so it is easily accessed via a midline celiotomy.[3]
- Infusion of balanced polyionic fluids such as saline[3] either directly into the impaction through the gastric wall (adjacent to the greater curvature) or via a nasogastric tube
- Massage of the stomach to reduce the impaction and aid movement of fluid into the ingesta
- Impactions diagnosed at surgery may benefit from bethanechol at 0.2mg/kg SC every 8 hours to stimulate gastric motility.[2]
- The stomach should be lavaged by nasogastric tube post-operatively and the horse starved for 48-72 hours.
- Gastroscopy is indicated to confirm resolution of the impaction and to identify any underlying causes in the stomach.[2]
Gastrotomy has been attempted to remove impacted stomach contents but this has largely been unsuccessful[10] and carries major risk including poor gastric motility and recurrence of the impaction.[11]
Prognosis
Infusion followed by postoperative gastric lavage by stomach tube is usually successful.[3] Chronic cases carry a poorer prognosis.
Prevention
- Regular dental care
- Ensure sugar beet nuts are adequately soaked prior to feeding
- Secure storage of roughage and hard feeds
- Ensure free access to water at all times
- Good pasture management to prevent ragwort poisoning
References
- ↑ Edwards, G.B (2003) 'Gastric Pathology' in Chuit, P, Kuffer, A, Montavon, S (2003) Congress on Equine Medicine and Surgery, International Veterinary Information Service (www.ivis.org), Ithaca, New York, USA.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Mair, T.S, Divers, T.J, Ducharme, N.G (2002) Manual of Equine Gastroenterology, WB Saunders.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Blikslager, A.T (2005) Treatment of Gastrointestinal Obstruction - Stomach Impaction, Ileal Impaction and Caecal Impaction, American Association of Equine Practitioners (AAEP), reproduced at www.ivis.org.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) Equine Internal Medicine (Third Edition), Saunders, Chapter 15.
- ↑ Kellam, L.L, Johnson, P.J, Kramer, J, Keegan, K.G (2000) Gastric impaction and obstruction of the small intestine associated with persimmon phytobezoar in a horse. J Am Vet Med Assoc, 216:1279-1281. In: Blikslager, A.T (2005) Treatment of Gastrointestinal Obstruction - Stomach Impaction, Ileal Impaction and Caecal Impaction, American Association of Equine Practitioners (AAEP), reproduced at www.ivis.org.
- ↑ Cummings, C.A, Copedge, K.J, Confer, A.W (1997) Equine gastric impaction, ulceration, and perforation due to persimmon (Diospyros virginiana) ingestion. J Vet Diagn Invest, 9:311-313. In: Blikslager, A.T (2005) Treatment of Gastrointestinal Obstruction - Stomach Impaction, Ileal Impaction and Caecal Impaction, American Association of Equine Practitioners (AAEP), reproduced at www.ivis.org.
- ↑ Honnas, C.M, Schumacher, J (1985) Primary gastric impaction in a pony. J Am Vet Med Assoc, 187:501-502. In: Blikslager, A.T (2005) Treatment of Gastrointestinal Obstruction - Stomach Impaction, Ileal Impaction and Caecal Impaction, American Association of Equine Practitioners (AAEP), reproduced at www.ivis.org.
- ↑ 8.0 8.1 8.2 8.3 Edwards, G.B (2003) 'Gastric Pathology' in Chuit, P, Kuffer, A, Montavon, S (2003) Congress on Equine Medicine and Surgery, International Veterinary Information Service (www.ivis.org), Ithaca, New York, USA.
- ↑ Milne, E.M, Pogson, D.M, Doxey, D.L (1990) Secondary gastric impaction associated with ragwort poisoning in three ponies. Vet Rec, 126(20):502-4.
- ↑ Edwards, G.B (2003) 'Gastric Pathology' in Chuit, P, Kuffer, A, Montavon, S (2003) Congress on Equine Medicine and Surgery, International Veterinary Information Service (www.ivis.org), Ithaca, New York, USA.
- ↑ Edwards, G.B (1997) 'Diseases of the Equine Stomach'. In: Proceedings of the 5th Congress of Equine Med Surg, 98-101.