Changes

Impaction of the large colon is seen in horses with limited access to drinking water or those grazing bare pastures. Horses fed on a low-roughage diet are more prone to developing the condition. The ingested sand accumulates and forms a sediment within the right dorsal colon, pelvic flexure and transverse colon. This type of colic is particularly common in dry sandy regions of the world and is far less common in the UK and rest of Europe.  

Impaction of the large colon is seen in horses with limited access to drinking water or those grazing bare pastures. Horses fed on a low-roughage diet are more prone to developing the condition. The ingested sand accumulates and forms a sediment within the right dorsal colon, pelvic flexure and transverse colon. This type of colic is particularly common in dry sandy regions of the world and is far less common in the UK and rest of Europe.  

===Clinical signs===

===Clinical signs===

Ingestion of sand without impaction may lead to clinical signs pertaining to a physical colitis due to the abrasive nature of sand. These may include diarrhoea, If sufficient sand has been ingested to cause an impaction, the clinical signs are generally dependent on the anatomical site affected. Horses affected by a pelvic flexure impaction often present with signs of mild abdominal pain and generally respond well to conservative treatment. Impaction of the transverse colon is often associated with more severe abdominal pain due to the build up of gas in the the colon proximal to the obstruction.  

Ingestion of sand without impaction may lead to clinical signs pertaining to a physical colitis due to the abrasive nature of sand. These may include diarrhoea, If sufficient sand has been ingested to cause an impaction, the clinical signs are generally dependent on the anatomical site affected. Horses affected by a pelvic flexure impaction often present with signs of mild abdominal pain and generally respond well to conservative treatment. Impaction of the transverse colon is often associated with more severe abdominal pain due to the build up of gas in the the colon proximal to the obstruction.  

===Diagnosis===

===Diagnosis===

Affected horses may have a history of living in a sandy environment, grazing in dry weather or a reduction in water intake. Definitive diagnosis is made via rectal palpation or transrectal ultrasonography with identification of sand in the colon. An impaction may also be detected per rectum, but in many cases the impacted segment is located in the cranial gastrointestinal tract and therefore out of reach. Transrectal ultrasonography may assist in identifying the presence of sand. Sand also may be seen in the faeces by mixing faecal material with water in a plastic rectal examination sleeve and allowing the sand to fall to the bottom.  

Affected horses may have a history of living in a sandy environment, grazing in dry weather or a reduction in water intake. Auscultation of the abdomen may reveal gritty-sounding 'rubs' heard as the sand moves through the colon. Definitive diagnosis is made via rectal palpation or transrectal ultrasonography with identification of sand in the colon. An impaction may also be detected per rectum, but in many cases the impacted segment is located in the cranial gastrointestinal tract and therefore out of reach. Transrectal ultrasonography may assist in identifying the presence of sand. Sand also may be seen in the faeces by mixing faecal material with water in a plastic rectal examination sleeve and allowing the sand to fall to the bottom.  

Abdominal radiography may be useful in assessing the volume and location of sand impactions in foals, minature horses and small ponies.  

Abdominal radiography may be useful in assessing the volume and location of sand impactions in foals, minature horses and small ponies.  

===Treatment===

===Treatment===