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==Description==

==Description==

Epiploic foramen entrapment in the horse refers to the displacement of a segment of small intestine through a small hole or foramen that separates the omental bursa from the peritoneal cavity. This form of obstruction accounts for between 2% and 8% of horses undergoing exploratory laparotomy for colic.  

Epiploic foramen entrapment in the horse refers to the displacement of a segment of small intestine through a small hole or foramen that separates the omental bursa from the peritoneal cavity. This form of obstruction accounts for between 2% and 8% of horses undergoing exploratory laparotomy for colic and is one of the most common forms of internal hernia in the horse.  

==Pathogenesis==

==Pathogenesis==

The epiploic foramen is located in the right dorsal abdomen and is bordered by the vena cava, hepatic portal vein, liver and pancreas. Most incarcerations are caused by small intestine passing from the left side of the abdomen through the epiploic foramen to the right side of the abdomen. The ileum and the jejunum are the most commonly incarcerated portions of small intestine.  

The epiploic foramen is located in the right dorsal abdomen and is bordered by the vena cava, hepatic portal vein, liver and pancreas. Most incarcerations are caused by small intestine passing from the left side of the abdomen through the epiploic foramen to the right side of the abdomen. The ileum and the jejunum are the most commonly incarcerated portions of small intestine. The length of bowel affected may vary from as little as 10cm to 17m. Strangulation of the affected portion occurs as a result of entrapment in the majority of cases, but minimal vascular impairment may result in the remainder of cases.

==Signalment==

==Signalment==

==Diagnosis==

==Diagnosis==

Definitive diagnosis of epiploic foramen entrapment may not be straightforward and is often made at surgery. Rectal palpation is often unrewarding due to the anterior position of the lesion but may reveal distended coils of small intestine. Nasogastric reflux is frequently present but may not lead to pain relief.  Transabdominal ultrasonography may reveal distended, hypomotile small intestine. Abdominocentesis is often useful to determine the degree of strangulation and peritoneal fluid may be serosanguineous with an increased lactate, total protein and leukocyte count. See also <big>'''[[:Category:Colic Diagnosis in the Horse|Colic Diagnosis in Horses]]

Definitive diagnosis of epiploic foramen entrapment may not be straightforward and is often made at surgery. Rectal palpation is often unrewarding due to the anterior position of the lesion but a marked pain response to traction of the caudal caecal band distended coils of small intestine are features that may distinguish epiploic entrapment from other conditions.  

 

Nasogastric reflux is frequently present but may not lead to pain relief.  Transabdominal ultrasonography may reveal distended, hypomotile small intestine. Small intestine identified in the right dorsal quadrant of the abdomen is highly suggestive of the disease. Abdominocentesis is often useful to determine the degree of strangulation and peritoneal fluid may be serosanguineous with an increased lactate, total protein and leukocyte count. See also <big>'''[[:Category:Colic Diagnosis in the Horse|Colic Diagnosis in Horses]]

==Treatment==

==Treatment==

Initial treatment consists of gastric decompression, fluid therapy and analgesia. See also '''[[Colic, Medical Treatment|Medical Treatment of Colic in Horses]]'''</big>  If epiploic foramen entrapment is suspected, surgical intervention is required. Surgical treatment of the condition is not straightforward due to the inaccessibility of the foramen and the delicate surrounding structures.  

Initial treatment consists of gastric decompression, fluid therapy and analgesia. See also '''[[Colic, Medical Treatment|Medical Treatment of Colic in Horses]]'''</big>  If epiploic foramen entrapment is suspected, surgical intervention is required. Surgical treatment of the condition is not straightforward due to the inaccessibility of the foramen and the delicate surrounding structures. A ventral midline exploratory coeliotomy is performed and palpation of small intestine (other than the duodenum) in the right dorsal quadrant of the abdomen will confirm diagnosis. The the encarcerated portion of intestine is reduced by gentle traction; decompression may be required prior to reduction if the segment is oedematous or filled with ingesta. Manual dilation of the foramen in order to aid reduction has been suggested by previous authors but this may lead to rupture of the portal vein and great care must be taken when doing so. The viability of the affected intestine is assessed and a resection and anastamosis may be performed if necessary.  

 

A ventral midline exploratory coeliotomy is performed and the the encarcerated portion of intestine is reduced by gentle traction. Decompression may be required prior to reduction if the segment is oedematous or filled with ingesta. Manual dilation of the foramen in order to aid reduction has been suggested by previous authors but this may lead to rupture of the portal vein and great care must be taken when doing so. The viability of the affected intestine is assessed and a resection and anastamosis may be performed if necessary.  

    

    

==Prognosis==

==Prognosis==

The prognosis following surgical treatment is fair with current reported short-term survival rates of 75% and  a 40-70% long term survival rate. The prognosis may be altered by the extent of strangulation observed at surgery and the presence of endotoxaemia.

The prognosis following surgical treatment is fair with current reported short-term survival rates of 75% and  a 40-70% long term survival rate. The prognosis may be altered by the extent of strangulation observed at surgery and the presence of endotoxaemia. Recurrence of epiploic foramen entrapment several months or years later has been reported in a small number of cases.

==References==

==References==