Changes

==Aetiology==

==Aetiology==

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.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.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.<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>

===Predisposing factors===

===Predisposing factors===

*Dropping of feed

*Dropping of feed

*Bruxism  

*Bruxism  

*Salivation (Edwards)

*Salivation<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>

*Insidious weight loss (if chronic)(Edwards)

*Insidious weight loss (if chronic)<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>

*Spontaenous 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>

*Spontaenous 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>

*'''Endoscopy''' would be indicated in a chronic case(Mair, Blisk) 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''' would be indicated in a chronic case(Mair, Blisk) 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>

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

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

*[[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. (Edwards)

*[[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>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>

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

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