Diagnosis,management and prognosis of small colon impactions

Common causes of obstruction of the small colon and rectum include diffuse faecal impaction, enterolithiasis, faecalithiasis, phytobezoar, trichobezoar, phytotrichobezoar, phytoconglobate, foreign body, intramural haematoma and retained meconium. Poor dentition, poor-quality hay, lack of adequate water, parasite damage and lack of exercise are risk factors for the development of small colon impactions. Clinical signs of small colon obstruction develop slowly because a large space proximal to the obstruction allows ingesta, gas and fluid to accumulate. Medical management of horses with faecal impaction of the small colon involves improvement of hydration, stimulation of colonic motility, softening the impaction by the administration of osmotic laxatives or lubricants, and control of pain. Surgical intervention is indicated when medical management fails to resolve the impaction or when intractable pain and a deteriorating cardiovascular status ensues.     

Diagnosis,management and prognosis of large colon impactions

The majority of large colon feed impactions occur in the left ventral colon at the pelvic flexure. Sand and enterolith impactions most commonly occur in the left ventral colon at the pelvic flexure or in the right dorsal colon; however, sand can accumulate anywhere along the gastrointestinal tract. Enteral fluid therapy can, in most cases, supplement or even replace i.v. administration of fluids and it appears effective and safe to soften large colon contents and resolve simple large colon impactions. Surgical intervention is indicated when a concurrent displacement is suspected, as lengthy medical treatment of large colon impaction secondary to large colon displacements would not be indicated and may increase the risk of colonic rupture. Other indications for surgical intervention include uncontrollable pain, when cardiovascular parameters deteriorate, or when there is evidence of intestinal devitalisation. The prognosis for horses undergoing large colon enterotomy is dependent on the extent and type of impaction, but is generally excellent.     

Parainguinal laparotomy as an alternative surgical approach for removal of an enterolith in the small colon of a horse

This report describes the use of a parainguinal approach to the abdomen to remove an obstruction in the small colon that could not be removed using an initial ventral midline approach. The use of a parainguinal approach should be considered for removal of an obstruction in the distal portion of the small colon.     

Successful small intestinal resection and anastomosis in a late term broodmare with colic via a standing left flank laparotomy

A late term broodmare presented with low‐grade intestinal colic. Clinical findings were consistent with a small intestinal lesion requiring surgical intervention. The risks of general anaesthesia to the fetus, combined with clinical findings in an otherwise quiet natured horse influenced the decision to choose an alternative standing left flank approach first. A small intestinal resection and anastomosis was performed successfully and the mare delivered a healthy foal without complications a month later. Standing colic surgery might be a preferred alternative to general anaesthesia in certain circumstances as discussed in this case report.     

Small colon stenosis secondary to ulcerative colitis in three Standardbred foals

Three Standardbred foals, a colt approximately one month old and 2 fillies approximately 4.5 months old, from the same farm, presented to University of Pennsylvania's New Bolton Centre over the course of 3 months for further evaluation due to acute onset of colic. All foals had a history of diarrhoea prior to presentation. On presentation, the foals had abdominal distension, dull demeanour and repeatedly lay down and rolled. Exploratory celiotomy revealed a segment of stenotic (lumen diameter 1–4 mm) small colon with marked distension of the colon proximal to the stenotic segment. Post mortem examination of the foals confirmed stenosis of the small colon with a segment of ulcerative colitis associated with the stenotic region. An aetiological agent was not identified.     

A standing pararectal approach to treat small colon obstruction by a pedunculated lipoma

In an 18-year-old Paso Fino mare presented with mild colic of 36 h duration, a luminal obstruction was found on rectal palpation in the most oral part of the rectum, and this appeared to be caused by a tight band on the left side. A standing procedure was used that involved pararectal dissection with long-handled instruments to the level of the constricting band, guided by a hand in the rectum. A hooked bistoury designed for treating entrapped epiglottis was used to transect the band, which immediately released the obstruction and allowed manual evacuation of the aboral end of the small colon. The band was most likely the pedicle of a pedunculated lipoma that had encircled the oral end of the rectum. The mare made a complete recovery.     

Retrospective study assessing efficacy of treatment of large colonic impactions

Cases with a history of colic due to a large colonic impaction were recruited retrospectively to assess the treatment efficacy and complications of oral and parenteral fluid therapy regimes for correction of primary large colon impactions. Oral isotonic fluids had been administered at varying intervals following initial treatment with magnesium sulphate and water. There was no significant difference in complication rates between groups. Considering complication rates with impaction clearance, hourly administration of oral fluids appears to be the most appropriate treatment regime of those investigated.     

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

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.     

The paradox of diarrhoeal disease and small colon obstruction

The interesting finding of stenosis in a case series of 3 foals that initially presented with diarrhoeal disease is suggestive of an inflammatory and fibrotic event that is more frequently reported in people with inflammatory bowel disease. In man, stenosis is believed to occur because of inflammation and excessive production of scar tissue in the absence of a normal reparative response. However, this is typically a chronic process, whereas in the foals, stenosis occurred within weeks to months. Other diseases of horses, particularly right dorsal colitis and small colon impaction preceded by diarrhoeal disease, have some similarities to the focal disease described for foals. Collectively, equine studies are increasingly pointing toward complex interactions in the intestinal tract between the mucosa, the microbiome, management factors such as diet, and reparative responses to inflammatory insult.     

Small colon obstruction by an ovarian pedicle as an acquired condition in a foal

This report describes the clinical course and the surgical findings in a 7‐day‐old foal referred for signs of abdominal pain. The foal underwent abdominal celiotomy due to the degree of pain unresponsive to medical treatment and, upon exploration, an ovarian pedicle was found to be wrapped around the small colon. The lesion was corrected, the foal recovered well from anaesthesia, and a 4 month follow‐up revealed no other signs of abdominal pain or complications.     

A case of a colocolic intussusception in a horse

The purpose of this report is to describe the clinical course and pathological findings in a horse admitted to the emergency service of the University of Georgia Large Animal Teaching Hospital for evaluation of colic, fever and diarrhoea of several days' duration. A presumptive historical diagnosis of colitis was made initially, but, due to the lack of faecal output during the first 12 h of hospitalisation and subsequent examination findings, an impaction of the ascending colon was suspected. Initial therapy consisted of rehydration with oral fluids and management of the abdominal pain with analgesic therapy. The horse did not respond to medical therapy and because of signs of persistent abdominal pain and financial constraints, the owner elected euthanasia after several days of supportive care. At necropsy, the horse was diagnosed with a colocolic intussusception.     

Entrapment of the small colon through a mesocolic rent in a mare

A 6-year-old mare was presented for acute abdominal pain unresponsive to analgesics. Exploratory laparotomy revealed entrapment of the small colon through a 12 cm rent in the mesocolon. The incarcerated small colon was manually reduced and the rent in the mesocolon was sutured closed. The mare made excellent postoperative recovery and was discharged from the hospital 4 days later. The cause of the rent, which was chronic in appearance, is unknown.     

T cell rich,B cell lymphoma in the small colon of a yearling horse

A one‐year‐old, Thoroughbred colt presented for evaluation due to a one month history of fever of unknown origin and progressive weight loss. On initial presentation, the horse was febrile and showed signs localised to the respiratory tract. These included bilaterally increased bronchovesicular sounds and a moderate, diffuse interstitial pattern on thoracic radiographs. A transtracheal wash yielded mucopurulent debris, culture of which grew small numbers of Staphylococcus epidermidis and Aspergillus spp. The horse was discharged with a diagnosis of bronchointerstitial pneumonia and placed on antibiotic therapy. Ten days after initial presentation, he developed abdominal pain that was unresponsive to on‐farm treatment. The horse was febrile, displayed increased respiratory rate and effort, and showed moderate signs of abdominal pain. On rectal examination, a firm, 8–10 cm mass was palpated on midline. The colt was admitted to the hospital and scheduled for exploratory laparotomy, but died a short time later before surgery could be performed. This report describes the clinical, diagnostic and histopathological findings of a case of alimentary lymphoma in a yearling colt.     

Permanent colostomy after small colon prolapse in a parturient mare

Small colon prolapse is a possible complication during parturition and diarrhoea. A case diagnosed in a mare during birth labour was reduced by the attending veterinarian at the farm, and referred to the authors for evaluation. After thorough physical examination, blood and peritoneal fluid tests, a ruptured mesocolon was suspected and the mare explored under general anaesthesia by a median celiotomy approach. During the procedure the affected mesocolon‐rectum was confirmed and a resection of the intestine elected. After prolapsing the segment of damaged viscera a permanent end colostomy was performed. Fourteen months later and after an uneventful recovery, the mare was in a very good physical condition and waiting to be covered for the next breeding season.     

Epiploic foramen entrapment of the large colon in a 9-month-old Thoroughbred filly

A 9-month-old Thoroughbred filly was presented for colic of a few hours’ duration. Examination revealed tachycardia at 64 beats/min, and a colon displaced to the right with wall oedema on ultrasound. After an hour of intravenous fluid therapy, the filly became restless and exploratory laparotomy was performed. Impaction and incarceration of the large colon up to the caeco-colic fold through the epiploic foramen (EF) were diagnosed. After evacuating the colonic contents through a pelvic flexure enterotomy, the EF entrapment (EFE) was reduced. The large colon appeared congested with a fragile serosa, serosal tear at its antimesenteric aspect, and amotile for the remainder of the surgery. Colon motility resumed as evidenced by ultrasonographic examination on the second day post-surgery, and despite pasty diarrhoea, the filly made a complete and uneventful recovery and was alive at 6 months’ follow-up. Epiploic foramen entrapment of the large colon is very rare but should be included as a differential diagnosis of colon displacements, even in young horses, requiring prompt surgical resolution.