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==Introduction==

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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>

|'''Colic<br>

'''Impaction<br>

'''Simple Obstruction'''

See also: '''[[Colic, Gastric Causes]]'''

Gastric impaction is rare in the horse.(Edwards)  It can occur spontaneously as a primary condition but is often secondary to other disturbances in the intestinal tract of the stomach such as ucleration of fibrosis at the pylorus.(Mair)  The condition typically causes mild to moderate colic that does not resolve with routine medical treatment.(Bliks)

==Aetiology==

==Aetiology==

The specific cause of the impaction is not always apparent(Sanchez) but the obstruction typically consists of excessive dry, coarse ingesta such as straw bedding or poor quality forage.(Sanchez)  It may also be composed of foreign bodies, ingested materials that form a mass (such as persimmon seeds or mesquite beans.1-3 in Bliks) or feeds that tend to swell after ingestion.(151-4 in Sanchez) Gastric impaction may be the result of an gastric atony or defective secretion.(Edwards)

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 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.(Mair)

*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 only partially masticated.(Mair)

*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

*Rapid consumption of feedstuffs.(Sanchezz)

*Rapid consumption of feedstuffs.<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>

*Inadequate water consumption.(Sanchez)

*Inadequate water consumption.<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>

*Secondary gastric impaction has been related to ragwort poisoning(Milne)

*Secondary gastric impaction has been related to ragwort poisoning<ref>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.</ref>

==Clinical signs==

==Clinical signs==

The colic associated with gastric impaction varies from mild and chronic to acute and severe.(Bliks)  Other signs reported include (Bliks):

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:

*Anorexia

*Anorexia

*Lethargy

*Lethargy

*Dropping of feed

*Dropping of feed

*Bruxism  

*Bruxism  

*Salivation (Edwards)

*Salivation<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>

*Insidious weight loss (if chronic)(Edwards)

*Insidious weight loss (if chronic)<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>

*Spontaenous reflux with gastric contents visible at the nares (in severe cases)(Sanchez)

*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>

In mild cases where signs resolve spontaneously or with analgesics, owners my continue to feed the horse, which only serves to worsen the impaction.(Mair)

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

*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>

*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>

*'''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>

*[[Colic Diagnosis - Abdominal Ultrasound|'''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.<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>

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

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

Endoscopy (not diagnostic for impaction and difficult to assess gastric distension) would be indicated in a chronic case(Mair, Blisk)

 

Rads may help, will show diaphragm displaced cranially(Mair)

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:

*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'''.<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>

*Infusion of balanced polyionic fluids such as saline<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> 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''' to stimulate gastric motility.<ref name="Mair">Mair, T.S, Divers, T.J, Ducharme, N.G (2002) '''Manual of Equine Gastroenterology''', ''WB Saunders''.</ref>

*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.<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>

However, the diagnosis of stomach impaction is usually made at surgery on horses that have had uncontrollable colic or poor response to medicaltherapy. (Bliks)

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.

Alateral radiograph of the cranial abdomen

showedthe stomach extending caudally from the diaphragm to the level of the 13th or14th intercostal space in several

*Secure storage of roughage and hard feeds

*Ensure free access to water at all times

If the horse sufferes from acute severe colic, a diagnosis os often made during exploratory celiotomoy. If signs do not warrant surgical intervnetion, endocosocpy showing a full stomahc after a norally adeqaute fast of 18-24hrs can often confirm the diagnosis. Abdominal rads are resrved for smaller horses and ponies.

|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]

==Treatment==

==References==