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'''Intussusception''' is the invagination of one portion of the gastrointestinal tract into the lumen of the adjacent portion.  The intussusceptum is the invaginated segment and the intussuscipien is the enveloping segment. A normograde intussusception is most common, but retrograde intussusception has also been reported.   

'''Intussusception''' is the invagination of one portion of the gastrointestinal tract into the lumen of the adjacent portion.  The intussusceptum is the invaginated segment and the intussuscipien is the enveloping segment. A normograde intussusception is most common, but retrograde intussusception has also been reported.   

Intussusceptions can be classified according to their location in the gastrointestinal tract. They usually occur in regions where there is a significant change in lumen diameter, such as ileocolic and gastroesphageal junctions. Ileocolic intussusceptions are most common, they frequently protrude from the rectum and must be distinguished from a rectal prolapse. In the case of an intussusception, it is possible to pass a probe next to the anus, but not in [[Rectal Prolapse|rectal proplapse]].

Intussusceptions can be classified according to their location in the gastrointestinal tract. They usually occur in regions where there is a significant change in lumen diameter, such as ileocolic and gastroesphageal junctions. Ileocolic intussusceptions are most common, they frequently protrude from the rectum and must be distinguished from a rectal prolapse. In the case of an intussusception, it is possible to pass a probe next to the anus, but not in a [[Rectal Prolapse|rectal proplapse]].

Depending on the site and severity, an intussusception results in a partial or complete obstruction to the gastrointestinal tract causing hypovolaemia, dehydration and shock. The condition is serious and should be treated as an emergency.   

Depending on the site and severity, an intussusception results in a partial or complete obstruction to the gastrointestinal tract causing hypovolaemia, dehydration and shock. The condition is potentially serious and should be treated as an emergency.   

===Pathogenesis===

===Pathogenesis===

[[Image:intussuceptionphoto.jpg|thumb|right|150px|Intersusception (Courtesy of Bristol BioMed Image Archive)]]

[[Image:intussuceptionphoto.jpg|thumb|right|150px|Intersusception (Courtesy of Bristol BioMed Image Archive)]]

Intussusception results from abnormal peristalsis. Vigorous contractions force the more proximal intestine to invaginate into the adjacent distal portion, taking its mesenteric attachment with it. Compression of the mesenteric vessels obstruct venous drainage, resulting in venous congestion, swelling and oedema. An inflammatory exudate is released from the serosal surface, fibrinous adhesions may form between surfaces making the structure irreducible this may progress to necrosis of the tissue.

Intussusception results from abnormal peristalsis. Vigorous contractions force the more proximal intestine to invaginate into the adjacent distal portion, taking its mesenteric attachment with it. Compression of the mesenteric vessels cause vascular compromise to the instestine, resulting in venous congestion, oedema and if the aterial supply is damaged full thickness necrosis. An inflammatory exudate is released from the serosal surface and fibrinous adhesions may form, making the structure irreducible.

The resulting functional obstruction to the intestine may cause it to rupture, leading to peritonitis and a high mortality rate.  

Intussusception normally occurs due to gastrointestinal disease, although it is often hard to identify the cause. Parasites, infectious enteritis, metabolic disorders, foreign bodies, history of recent intestinal surgery, intestinal masses have all been known to associate with intussusception.  Chronic intussusception can occur with little haemodynamic changes.

Intussusception normally occurs due to gastrointestinal disease, although it is often hard to identify the cause. It is associated with any condition that increases peristalsis such as

*Associated with any condition that increases peristalsis  

** Enteritis

** Enteritis

** Foreign body

** Foreign body

German shepherd dogs and Siamese cats are over represented. German Shepherd dogs are particularly predisposed to gastroesophageal intussusception.   

German shepherd dogs and Siamese cats are over represented. German Shepherd dogs are particularly predisposed to gastroesophageal intussusception.   

===Age===

===Age===

Young animals are most commonly affected, 80% of cases are less than a year old.

Young animals are most commonly affected, 80% of cases are less than a year old.  

 

==Diagnosis==

==Diagnosis==