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==Description==

==Introduction==

Gastric impaction can occur as a primary condition but is often diagnosed at surgery as a finding secondary to other disturbances in the intestinal tract.  In some cases there be predisposing causes such as ulceration or fibrosis at the pylorus, whereas in other cases it may occur spontaneously.

Gastric impaction is rare in the horse.<ref>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.</ref>  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.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>  The condition typically causes mild to moderate colic that does not resolve with routine medical treatment.<ref name="Bliks">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.</ref>

==Aetiology==

==Aetiology==

Impaction of the stomach typically consists of excessive dry, fibrous ingesta, but may also be composed of ingested materials that form a mass, suchas persimmon seeds or mesquite beans.1-3 Other feeds that tend to swell after ingestion, including wheat, barley, and sugar beet pulp, may also cause impaction. Furthermore, dental disease may increase the likelihood of gastric impaction because of improper chewing of feed. (Bliks)

The specific cause of the impaction is not always apparent<ref name="Sanchez">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.</ref> but the obstruction typically consists of excessive dry, coarse ingesta such as straw bedding or poor quality forage.<ref name="Sanchez">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.</ref>  It may also be composed of foreign bodies, ingested materials that form a mass (such as persimmon seeds or mesquite beans<ref>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.</ref><ref>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.</ref><ref>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.</ref>) or feeds that tend to swell after ingestion.  Gastric impaction may be the result of a gastric atony or defective secretion.<ref name="Edwards">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.</ref>

===Predisposing factors===

===Predisposing factors===

*Ingestion of certain feedstuffs including 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

*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.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

*Dental disorders - roughage may be incompletely masticated

*Dental disorders - roughage may be only partially masticated.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

*Feeding a horse that has signs of colic - there may be poor gastric emptying associated with generalised decreased gastrointestinal motility

*Feeding a horse that has signs of colic - there may be poor gastric emptying associated with generalised decreased gastrointestinal motility

==Clinical signs==

==Clinical signs==

The [[Colic Diagnosis - Clinical Signs|colic]] associated with gastric impaction varies from mild and chronic to acute and severe.<ref name="Bliks">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.</ref>  Other signs reported include:

If the signs are mild and resolve spontaneously or with analgesics, owners often inclined to feed the horse, worsening the impaction

*Dropping of feed

*Spontaneous reflux with gastric contents visible at the nares (in severe cases)<ref name="Sanchez">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.</ref>

Clinical signs of colic range from acute and severe to chronic and mild. For example, in one report on 4 horses with gastric impaction, colic was moderate or severe and of 8-12 hours’ duration,4 whereas in another report on a pony with gastric impaction, colic was chronic (7 days’ duration), associated with prolonged recumbency, anorexia, and lethargy.3 Additional signs may include dysphagia, dropping of feed, and bruxism.3,5

In mild cases where signs resolve spontaneously or with analgesics, owners my continue to feed the horse, which only serves to worsen the impaction.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

==Diagnosis==

==Diagnosis==

Suspected if cannot pass NGT, with gastric distension the gastoroesophageal junction can become distorted making it difficult to pass an NGT

*Gastric impaction is suspected if a [[Colic Diagnosis - Naso-gastric Intubation|'''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.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

If poorly macerated or digested feed material is recovered from the NGT when the horse has been starved for several hrs

*On [[Colic Diagnosis - Rectal Examination|'''rectal examination''']], the spleen may be displaced caudally and medially (but this is not specific for gastric impaction).<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

On rectal, spleen may be displaced caudally and medially (not specific)

*'''Endoscopy''' would be indicated in a chronic case<ref name="Bliks">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.</ref> and may show a full stomach after a fast of 18-24hrs.<ref name="Sanchez">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.</ref>  However it is not diagnostic for impaction as it is difficult to assess gastric distension by endoscopy.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

Endoscopy (not diagnostic for impaction and difficult to assess gastric distension)

*In a small horse or pony, a lateral '''radiograph''' of the cranial abdomen may show the diaphragm displaced cranially

Rads may help, will show diaphragm displaced cranially

However, the diagnosis of stomach impaction is usually made at surgery on horses that have had uncontrollable colic or poor response to medicaltherapy. However, endoscopy will reveal gastric impaction, and may provide information on the specific nature of the impaction. Although this would nottypically be performed on an acute colic case, it would be indicated in a horse with chronic colic. (Bliks)

'''However, if the horse suffers from acute severe colic, a diagnosis is often made at surgery'''.

==Treatment==

==Treatment==

If suspected, horse should be tranferred with NGT in place to a faciltiy where surgery can be perfomed if necessary

If gastric impaction is suspected, the horse should be transported with a '''nasogastric tube''' in place to a clinic with surgical facilities.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>  [[Colic, Medical Treatment|'''Medical treatment''']] might include gastric lavage with water<ref name="Bliks">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.</ref> 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.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>  Owing to the risk of gastric rupture, gastric motility stimulants should be avoided if the extent of the impaction is undetermined.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>  At surgery the following should be performed:

Medical tx can include gastric lavage to remove as much impacted material as possible - may need to be done repeatedly

100-200ml 8%DSS may facilitate hydration of dessicated ingesta

IV fluid and anlagesics should also be given, although unlikely that IV fluids will resolve the impaction

*Massage of the stomach to reduce the impaction and aid movement of fluid into the ingesta

Gastric motility stimulants should be avoided if the extent of the impaction is unkown to prevent gastric rupture

*Impactions diagnosed at surgery may benefit from '''bethanechol''' to stimulate gastric motility.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

Those diagnosed at sx may be treated with bethanecol at 0.2mg/kg SC every 8hrs

*The stomach should be lavaged by nasogastric tube post-operatively and the horse starved for 48-72 hours.

Medical treatment includes nasogastric intubation, and frequent attempts at softening the ingesta with water, followed by refluxing the fluid contents. (BLiks)

*'''Gastroscopy''' is indicated to confirm resolution of the impaction and to identify any underlying causes in the stomach.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

 

'''Gastrotomy''' has been attempted to remove impacted stomach contents but this has largely been unsuccessful<ref>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.</ref> and carries major risk including poor gastric motility and recurrence of the impaction.<ref>Edwards, G.B (1997) 'Diseases of the Equine Stomach'. In: ''Proceedings of the 5th Congress of Equine Med Surg'', 98-101.</ref>

 

Infusion followed by postoperative gastric lavage by stomach tube is usually successful.<ref name="Bliks">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.</ref>  Chronic cases carry a poorer prognosis.  Untreated, gastric impaction may lead to [[Gastric Dilation and Rupture - Horse|'''gastric rupture''']] which is fatal.

Stomach massaged to break down impaction and facilitate movement of fluid into the ingesta

*Ensure sugar beet nuts are adequately soaked prior to feeding

Or fluid may be infused via NGT followed by massage of the stomach

*Secure storage of roughage and hard feeds

Gastroscopy indicated to confirm resolution of impaction and identify any underlying causes in stomach

*Good pasture management to prevent ragwort poisoning

At surgery, the impaction can be massaged and infused, most commonly via insertion of a needle adjacent to the greater curvature, followed by infusionof a balanced polyionic fluid such as saline. There is also a report including the details of a pony and a horse in which a gastrotomy was performed to removethe impacted stomach contents.5 However, there are major risks with this procedure, and infusion followed up by postoperative lavage by stomach tube isusually successful. (Bliks)

|literature search = [http://www.cabdirect.org/search.html?q=%28title%3A%28gastric%29+OR+title%3A%28stomach%29%29+AND+title%3A%28impaction%29+AND+od%3A%28horses%29 Gastric impaction in horses publications]

==References==

==References==

 

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