244
EQUINE VETERINARY EDUCATION / AE / MAY 2018
Mean s.d.
TABLE 1: Blood values (mean, s.d., range and median) of 60 horses with caecal intussusception PCV 39
BE 7.83
Range Median
Reference
24–60 38
35–45%
1.51 4.33
11 to 8.7 2.75
5–5 PCV, packed cell volume; BE, base excess.
TABLE 2: Overview of outcome and surgical technique used in 60 horses with caecal intussusception Treatment
Survived to discharge Euthanasia
Caecocaecal intussusception (n = 14) Euthanasia Surgery
4 Simple reduction
Euthanasia during surgery
10 4
Partial typhlectomy 5
Caecocolic intussusception (n = 46) Euthanasia Surgery
Simple reduction
Colostomy + partial typhlectomy
Euthanasia during surgery
18 28 9
Partial typhlectomy 8 /
8 3 5
/
2 1 0
1/ 1 /
17 9 6
/
11 0 2
42 2 7/ 7
contamination of the abdomen. In 9/28 (32%) only surgical reduction was performed, while 8/28 (28%) needed partial typhlectomy. One of these horses also needed a side-to-side ileocaecal bypass because of severe oedema at the ileocaecal valve. Four (14%) horses had an unreducible intussusception and underwent partial typhlectomy via colostomy with a natural rubber ligature (Wiemer and Van der Veen 1999). Four of the operated horses (14%) horses did not survive because they died during anaesthetic recovery after colostomy (n = 2) or were subjected to euthanasia after surgery due to peritonitis (n = 1) or hyperlipaemia (n = 1), both after a partial typhlectomy. Seventeen out of 28 (61%) horses subjected to surgery survived to discharge. Seventeen out of 19 (89%) horses successfully operated for caecocolic intussusception survived to discharge. Of all horses subjected to surgery, in 13/38 (34%) reduction
was possible, while 13/38 (34%) needed partial typhlectomy, 4/38 (10%) needed colostomy and 8/38 (21%) were subjected to euthanasia during surgery. Survival to discharge after successful surgery was 92% (12/13) if simple reduction was performed, 84% (11/13) if partial typhlectomy was needed and 50% (2/4) after colostomy. Horses that did not undergo surgery due to financial restrictions, were either subjected to euthanasia (n = 16) or conservative treatment was attempted, without success (n = 6). In those 22 horses, definite diagnosis was made on necropsy.
Discussion
In this retrospective study 60 horses suffering from caecal intussusception were included. Caecocolic intussusception
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(n = 46) was more common than caecocaecal intussusception (n = 14). In all horses, caecal intussusception was visible on abdominal ultrasound and in 92% (55/60) of the cases ultrasonography allowed us to correctly differentiate between caecocolic and caecocaecal intussusceptions. During this study however, two horses with a presumptive ultrasonographic diagnosis of caecocaecal intussusception were diagnosed with severe typhlitis at surgery or necropsy. Both caecocaecal and caecocolic intussusceptions have been described in the veterinary literature but large studies on ultrasonographic differentiation between the two are currently lacking (Gaughan and Hackett 1990; Martin et al. 1999; Boussauw et al. 2001; Bell and Textor 2010). In this study, the prevalence of caecal intussusception
was low (1.8%) but was similar to those reported elsewhere (Huskamp 1982; Gaughan and Hackett 1990; Boussauw et al. 2001). Horses suffering from caecal intussusception were usually young, the median age being 2 years. In the age category under 2 years, caecal intussusception accounted for more than 10% of the colic cases, making it an important differential diagnosis for colic in young horses. However, as is described in literature, all age categories can be affected (Martin et al. 1999). Diagnosis of caecal intussusception can be challenging,
since rectal palpation is not always conclusive. Furthermore, since the condition occurs most frequently in young horses, often yearlings, rectal palpation can be difficult, making ultrasonography a valuable diagnostic tool. Usually, caecal intussusceptions are ultrasonographically characterised by multiple concentric rings of varying thickness and echogenicity, a so-called target lesion, in the right abdomen (Scharner et al. 2002; Reef et al. 2004; Scheidemann and Huskamp 2011). The oedematous intussusceptum has hyperechoic margins surrounded by a layer of intestinal fluid (Reef 1998; Taintor et al. 2004). Often there is also evidence of peritoneal effusion (Scharner et al. 2002). In our case study, all intussusceptions could be visualised and in >90% of the cases correct differentiation before surgery could be made with transabdominal ultrasound. Caecocolic intussusceptions were often seen as a target-like sign, with characteristics as described above, most often located in the right cranioventral third of the abdomen, whereas caecocaecal intussusceptions more commonly appeared as an oedematous disorganised tissue mass in the right dorsal two-thirds of the abdomen. While the caecocolic intussusception consists of the congested intussusceptum surrounded by the often normal colon wall, the caecocaecal intussusception usually consists of two layers of oedematous bowel wall, the intussuscipiens and the intussusceptum, resulting in an oedematous structure without a typical concentric circle appearance. Occasionally, this image
Sodium (mmol/L) 130
5.46
116–143 132
132–141
Potassium (mmol/L) 3.46
0.49
2.7–5.5 3.45
2.7–4.9
Calcium (mmol/L) 1.3
0.3
0.93–2.79 1.26
1.4–1.6
Total protein (g/L) 48
8.4
38–54 51.5
46–69
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