Idiopathic eosinophilic colitis lesions of the equine small (descending) colon

Abstract

Summary Five horses with a primary surgical lesion of the small (descending) colon were diagnosed with eosinophilic colitis based on visual and histopathological examination. These were evident as visibly striking, hyperaemic, focal lesions of the small colon, with serosal petechiation, oedema and marked thickening of the intestinal wall at the site. Areas of focal necrosis were also evident. The gross appearance of the lesions were considered to be sufficiently severe in all cases to merit resection, due to concerns about intestinal necrosis and septic peritonitis. An inability to fully exteriorise the affected portion of intestine to perform a resection and anastomosis necessitated intraoperative euthanasia of one horse. A total of three horses survived to hospital discharge. Eosinophilic colitis lesions are a rare cause of severe small colon disease, but should be considered in cases with similar visual characteristics.

Eosinophilic intestinal diseases of the horse

“…In addition to having eosinophilic infiltration of intestine (usually large colon), horses with MEED have eosinophilic infiltration of the liver, pancreas, oesophagus, skin, blood and oral cavity (Lindberg et al 1985;Nimmo Wilkie et al 1985;Gibson and Alders 1987;La Perle et al 1998). Horses with MEED are often presented for weight loss, lethargy, subcutaneous oedema and skin disease, and, rarely, respiratory disease, whereas horses with eosinophilic infiltrates confined to the intestinal tract are usually presented for signs of abdominal pain (Scott et al 1999;Edwards et al 2000;Southwood et al 2000;Swain et al 2003;Archer et al 2006;Perez Olmos et al 2006;Makinen et al 2008;De Bont et al 2013, 2018Archer et al 2014). Horses with MEED almost never survive, whereas the prognosis for survival for horses with EDCI tends to be favourable, even though the treatment may include celiotomy with intestinal decompression or resection and administration of a corticosteroid.…”

“…Definitive diagnosis of EDCI is more difficult, because celiotomy is necessary to obtain tissue for histological examination. Provisional diagnosis of EDCI is made while horses are undergoing exploratory celiotomy performed because of abnormalities found during examination of the abdomen per rectum or during ultrasonographic examination, abnormal appearance of peritoneal fluid and/or signs of signs of unremitting abdominal pain (Edwards et al 2000;Archer et al 2006;Makinen et al 2008;De Bont et al 2013, 2018.…”

“…When the ascending colon is observed to be affected with SEC during exploratory celiotomy, resection of the diseased segment may not always be necessary but nevertheless is advised because eventual necrosis of affected colon is likely (Edwards et al 2000). Resection of affected colon is also likely to be necessary when SEC involves the descending colon (De Bont et al 2018). Medical treatment of horses for MEED or EDCI generally involves administering a corticosteroid, even though the efficacy of corticosteroids for treatment for EDCI is not proven, and except for rare cases of MEED (Gibson and Alders 1987; McCue et al 2003), treatment with a corticosteroid provides only short-term improvement (Lindberg et al1985).…”

“…; De Bont et al . , ), IFEE and DEE might have a similar aetiology and pathogenesis. The aetiology and pathogenesis of MEED probably differs from that of IFEE and DEE, and unquestionably, horses with MEED have a worse prognosis for survival than do horses with EDCI.…”

“…Resection of affected colon is also likely to be necessary when SEC involves the descending colon (De Bont et al . ). Medical treatment of horses for MEED or EDCI generally involves administering a corticosteroid, even though the efficacy of corticosteroids for treatment for EDCI is not proven, and except for rare cases of MEED (Gibson and Alders ; McCue et al .…”