EQUINE VETERINARY EDUCATION Equine vet. Educ. (2018) 30 (5) 241-246 doi: 10.1111/eve.12798


Case Report


Caecal intussusception in the horse: Ultrasonographic findings and survival to hospital discharge of 60 cases (2009–2013) E. Paulussen† ,B. Broux† ,T.van Bergen‡ ,L.Lef


ere†,D.DeClercq† andG. van Loon†*


†Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, and ‡Department of Surgery and Anaesthesiology of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium. *Corresponding author email: gunther.vanloon@ugent.be


Keywords: horse; colic; caecocaecal; caecocolic; ultrasonography; invagination


Summary Diagnosis of caecal intussusception can be challenging. Transabdominal ultrasound is often used as a diagnostic tool in equine colic. Differentiation between caecocaecal and caecocolic intussusception might be useful in the decision process before surgery. The aims of this study were: 1) to assess the usefulness of ultrasound for diagnosis of intussusception and differentiation between caecocaecal and caecocolic intussusception; and 2) to determine survival to hospital discharge after surgery. Therefore, a retrospective case series (2009–2013) was performed of all colic cases with caecal intussusception (n = 60) confirmed at surgery or necropsy. In all horses, the intussusception could be visualised using ultrasound at admission. Caecocolic intussusception (n = 46) was much more common than caecocaecal (n = 14) intussusception and correct ultrasonographic differentiation between both types could be made in 92% of the cases. Ten horses (out of 14) diagnosed with caecocaecal intussusception underwent surgery, of which 8/10 (80%) were discharged, one horse (10%) was subjected to euthanasia during and one (10%) after surgery. Of the 28 (out of 46) operated horses with caecocolic intussusception, 17 (61%) survived to discharge, while 7 (25%) and 4 (14%) were subjected to euthanasia during and after surgery, respectively. Of all horses that underwent surgery, in 13/38 (34%) surgical reduction was possible, while 13/38 (34%) needed partial typhlectomy and 4/38 (11%) needed colostomy because of an irreducible intussusception. Survival to discharge after successful surgery was 12/13 (92%) when only reduction was performed, 11/13 (85%) if partial typhlectomy was needed and 2/4 (50%) after colostomy and partial typhlectomy. In conclusion, abdominal ultrasound is a useful tool in the diagnosis and differentiation of caecal intussusception. Survival to hospital discharge after successful surgery is good.


Introduction


Caecal intussusceptions most commonly occur in yearlings and young adults and accounts for approximately 2% or less of all colic cases in the horse (Huskamp 1982; Gaughan and Hackett 1990; Dart et al. 1997; Johnson et al. 1999; Martin et al. 1999). Intussusception is defined as the invagination of one portion of bowel into an adjacent bowel segment. In the case of caecocaecal intussusception, the caecal apex inverts into the caecal body. If this situation progresses and the caecal apex and body invert through the caecocolic orifice into the


right ventral colon, the condition is called a caecocolic intussusception. Intussusceptions are believed to result from local motility disorders, inflammation of a part of abnormal bowel wall, possibly caused by dietary changes, colitis or typhlitis, administration of parasympathomimetic drugs or unknown reasons (Bell and Textor 2010). Also, the presence of Anoplocephala perfoliata and cyathostominosis has been related to the occurrence of caecal intussusception (Proudman and Edwards 1993; Proudman and Trees 1999; Mair et al. 2000; Gasser et al. 2005). Clinical signs are nonspecific and vary according to the degree of luminal obstruction. They commonly include acute or chronic colic signs, ranging from mild to severe, chronic weight-loss, diarrhoea and fever (Dart et al. 1997). Diagnosing caecal intussusception can be challenging. An oedematous mass in the right caudal aspect of the abdomen can sometimes be palpated on rectal examination, but rectal examination can be difficult to perform in young horses or small ponies (Scheidemann and Huskamp 2011). Cytological evaluation of peritoneal fluid collected by abdominocentesis may be normal or abnormal (Martin et al. 1999). Abdominal ultrasonography has been suggested to be useful for the detection of caecal intussusception. A target or bull’s-eye sign in the upper right abdominal quadrant has been described (Reef 1998; Bell and Textor 2010). At exploratory laparotomy, caecocaecal intussusception may require straightforward reduction of the intussuscepted portion of caecum. If there is too much vascular compromise to the caecal apex, partial typhlectomy can be performed following ligation of the medial and lateral caecal vessels (Martin et al. 1999). Surgical management of irreducible caecocolic intussusception is more difficult and the optimal surgical technique is an area of debate. The key surgical principle is to remove necrotic tissue whilst minimising contamination. Huskamp reported a technique that leaves the intussuscepted part in place to undergo necrosis in the colon (Huskamp 1988). Although this technique avoids abdominal contamination colic signs remain as long as the intussuscepted part is in place. Ileocolostomy leaving the intussuscepted caecum in place can be successful (Tyler 1992) but should be used as a last resort as the necrotic tissue can lead to peritonitis or death (Gaughan and Hackett 1990; Martin et al. 1999). Alternatively, the invaginated caecum can be assessed through a colostomy (Martin et al. 1999; Hubert et al. 2000). Reduction through this approach is seldom achieved but invaginated caecum can be pulled into the right ventral colon and amputated after suturing proximal to the site of amputation, ligating the caecum with umbilical tape (Hubert


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