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==Introduction==

'''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.

 

==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.

There are numerous causes which can be categorised as follows:

There are numerous causes which can be categorised as follows:

'''Mechanical obstruction'''<br>  

'''Mechanical obstruction'''<br>  

An obstruction of the colon or rectum will cause faecal material to become impacted and dry. The obstruction may be intraluminal such as a foreign body, polyp, mass or stricture. Extraluminal obstruction can be due to a mass, abscess, and prostatic diseases such as prostatic cyst, mass and [[Prostatic Enlargement|prostamegaly]]. A diverticulum to the colon or rectum, or a perineal hernia interupts the normal passage of faeces and may result in an impaction.  

An obstruction of the colon or rectum will cause faecal material to become impacted and dry. The obstruction may be intraluminal such as a foreign body, polyp, mass or stricture. Extraluminal obstruction can be due to a mass, abscess, and prostatic diseases such as prostatic cyst, mass and prostamegaly. A diverticulum to the colon or rectum, or a perineal hernia interupts the normal passage of faeces and may result in an impaction.  

'''Colonic weakness'''<br>

'''Colonic weakness'''<br>

A systemic disease causing abnormalities in electrolytes, such as [[Hypercalcaemia - Small Animal|hypercalcaemia]], hypokalemia can affect peristaltic contractions; the endocrine disorder [[Hypothyroidism|hypothyroidism]] also results in colonic weakness. Idiopathic [[Megacolon|megacolon]] is a significant cause of impaction especially in cats.   

A systemic disease causing abnormalities in electrolytes, such as hypercalcaemia, hypokalemia can affect peristaltic contractions; the endocrine disorder [[Hypothyroidism|hypothyroidism]] also results in colonic weakness. Idiopathic [[Megacolon|megacolon]] is a significant cause of impaction especially in cats.   

   

   

'''Problems with defecation'''<br>

'''Problems with defecation'''<br>

Environmental and behavioural factors are also important; a change in routine or household, or excessive stress can prevent animals from defecating normally. Animals also avoid defecation if it is painful due to anal sac disease, trauma to the perineal area, or they are unable to assume a normal position to defecate because of a fractured pelvis or another orthopaedic, condition.  

Environmental and behavioural factors are also important; a change in routine or household, or excessive stress can prevent animals from defecating normally. Animals also avoid defecation if it is painful due to anal sac disease, trauma to the perineal area, or they are unable to assume a normal position to defecate because of a fractured pelvis or another orthopaedic, condition.

==Signalment==

==Signalment==

Animals most commonly affected depend on the cause of the impaction. Significant risk factors include metabolic disease causing [[Dehydration - Pathology|dehydration]],inappropriate diet, and drug therapy affecting gastrointestinal motility such as [[Opioids|opioids]] and anticholinergics.   

Animals most commonly affected depend on the cause of the impaction. Significant risk factors include metabolic disease causing [[Dehydration|dehydration]],inappropriate diet, and drug therapy affecting gastrointestinal motility such as [[Opioids|opioids]] and anticholinergics.   

==Diagnosis==

==Diagnosis==

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.

Owners should be educated with regard to management. An appropriate wet diet should be fed, dietary supplementation with bran is helpful in some cases, fresh water should be freely available and activity should be encouraged.

Owners should be educated with regard to management. An appropriate wet diet should be fed, dietary supplementation with bran is helpful in some cases, fresh water should be freely available and activity should be encouraged.

Antiduirectic and anticholinergic drugs should be avoided.  

Antidiurectic and anticholinergic drugs should be avoided.  

===Surgery===

===Surgery===

==Prognosis==

==Prognosis==

Prognosis varies depending on the underlying cause.  

Prognosis varies depending on the underlying cause.  

==References==

==References==

* Tilley, L.P. and Smith, F.W.K.(2004)'''The 5-minute Veterinary Consult(Third edition)''' ''Lippincott, Williams & Wilkins''.

* Tilley, L.P. and Smith, F.W.K.(2004)'''The 5-minute Veterinary Consult(Third edition)''' ''Lippincott, Williams & Wilkins''.

[[Category:Intestine_-_Mechanical_Obstruction]][[Category:Dog]][[Category:Cat]]

 

[[Category:To_Do_-_lizzyk]]

[[Category:To_Do_-_Review]]

 

[[Category:Intestine_-_Mechanical_Obstruction]][[Category:Intestinal Diseases - Dog]][[Category:Intestinal Diseases - Cat]]

[[Category:Expert_Review]]