Changes

==Description==

==Description==

'''Colonic impaction''' is intractable constipation which can occur in all species, including the dog and cat. There are hardened faeces in the colon and a delayed or failure of faecal passage. The slower transit time allows more salt and water to be reabsorbed, leaving drier faeces in the colon which are more difficult to pass. Peristalsis may increase initially but is then significantly reduced or even absent due to chronic distension. Chronic cases may progress to Obstipation, the faeces become so hard and dry that defecation is no longer possible and ultimately there is secondary degeneration of the colonic musculature.

'''Colonic impaction''' is intractable constipation which can occur in all species, including the '''dog''' and '''cat'''. There are hardened faeces in the colon and a delayed or failure of faecal passage. The slower transit time allows more salt and water to be reabsorbed, leaving drier faeces in the colon which are more difficult to pass. Peristalsis may increase initially but is then significantly reduced or even absent due to '''chronic distension'''. Chronic cases may progress to Obstipation, the faeces become so hard and dry that defecation is no longer possible and ultimately there is secondary degeneration of the colonic musculature.

There are numerous causes which can be categorised as follows:

There are numerous causes which can be categorised as follows:

* Vomiting  

* Vomiting  

On abdominal palpation the colon is filled with firm faecal material.  

On '''abdominal palpation''' the colon is filled with firm faecal material.  

Digital rectal examination will reveal hardened faecal balls; there may be a palpable mass or stricture, anal sac disease or perineal hernia depending on the cause.

'''Digital rectal examination''' will reveal hardened faecal balls; there may be a palpable mass or stricture, anal sac disease or perineal hernia depending on the cause.

===Ultrasound===

===Ultrasound===

The treatment depends on the severity and duration of the impaction.  

The treatment depends on the severity and duration of the impaction.  

Dehydrated patients should receive IV fluid therapy, with correction of any concurrent electrolyte and acid-base abnormalities.

Dehydrated patients should receive '''IV fluid therapy''', with correction of any concurrent electrolyte and acid-base abnormalities.

A warm water enema can be used to soften and allow the impaction to pass. Laxatives such as Emollient laxatives (docusate sodium), Stimulant laxatives (bisacodyl), saline laxatives and disaccharide laxatives (lactulose) are also beneficial. Mineral oil and white petroleum lubricants should be avoided due to the risk of aspiration because of their tasteless nature.  

A warm water '''enema''' can be used to soften and allow the impaction to pass. '''Laxatives''' such as Emollient laxatives (docusate sodium), Stimulant laxatives (bisacodyl), saline laxatives and disaccharide laxatives (lactulose) are also beneficial. Mineral oil and white petroleum lubricants should be avoided due to the risk of aspiration because of their tasteless nature.  

Cisapride, a motility modifier is indicated in early cases of megacolon but is contraindicated in cases of obstruction.

Cisapride, a motility modifier is indicated in early cases of megacolon but is contraindicated in cases of obstruction.