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EQUINE VETERINARY EDUCATION / AE / AUGUST 2020
Results
Twenty-nine cases (24 females, one gelding and four intact males) met the inclusion criteria and were enrolled in the study. Females were overrepresented compared to the surgical colic population in the hospital in which females represent 66% (P = 0.003). Nine mares were pregnant at the time of presentation, with a mean pregnancy duration of 7.6 months. The study population had a mean age of 4.2 years (median, 4 years; range, 4 months to 12 years). The predominant breed was Arabian (n = 22), followed by Quarter Horses (n = 2), mixed breed (n = 2) and one each of Paint Pony, Tennessee Walking Horse and a donkey. Arabians were overrepresented in the current study compared to the surgical colic population in which the Arabians represent 39% (P<0.001). The age distribution for the study population reflected that for horses undergoing colic surgery at the hospital. Mean time between onset of clinical signs of colic and admission was 1.8 days (median, 1 day; range, 2 h– 10 days). Most animals (n = 20) were admitted to the hospital with less than 48 h of colic signs. No significant difference was seen regarding season of referral which distributed as follows: Winter – eight cases, Spring – eight cases, Summer – five cases and Autumn – eight cases. Seventeen horses had a mention in the medical files regarding manure passage during the colic episode prior to referral and the majority of them had not passed any faeces (n = 12) or passed a very small amount of hard faecal balls (n = 5). Seven horses were housed in a small paddock or at pasture and were given free access to hay, six horses were housed solely in a stall with measured amounts of feed and the remaining horses had unknown housing and feeding habits due to missing data. Only two horses had known access to foreign material in the diet (baling twine). On physical examination, most cases were tachycardic
(mean, 62 beats/min; range, 40–96 beats/min) and afebrile (mean, 37.7°C; range, 37–39.2°C), however, six horses exhibited temperatures outside of the normal parameters, with those temperatures ranging from 38.5 to 39.2°C. Mucous membranes were discoloured in 13 cases, of which 10 cases had hyperaemic mucous membranes. Abdominal distention was present in 27 cases, of which 22 were subjectively considered to suffer from moderate-severe distention. On rectal palpation, 17 cases were diagnosed with a large colon distention, two horses were diagnosed with a large colon impaction and two cases did not undergo a rectal examination. The FB was felt in only six cases and in three horses no abnormalities were recognised during rectal palpation. Nasogastric intubation yielded gastric reflux in 11 cases with a mean reflux volume on arrival of 1.5 L (range 0–7 L). Twenty-two cases underwent exploratory celiotomy on
the day of admission. The reasons to go to surgery were as follows – insufficient response to medical treatment for at least 12 h hospitalisation (n = 9), severe pain on arrival combined with moderate or severe abdominal distention (n = 13), severe pain on arrival with signs of endotoxaemia (hyperaemic mucous membranes with or without a gingival toxic line, heart rate >60 beats/min, temperature >38.5°C) (n = 5). Two cases were referred for surgery after intensive treatment at home for more than 2 days without success. Overall, 33 FBs were discovered during surgery and found to be the cause for the colic. In surgery, 25 cases had a
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single FB which was found in the small colon (n = 15), transverse colon (n = 9) or right dorsal colon (n = 1). Four cases were found to have two FBs located in both the small and large colons. Foreign bodies were significantly more common in the small colon in comparison to the large colon (P<0.0001). There was no significant difference between cases suffering from a FB in the small colon compared with the large colon regarding the signalment, clinical signs, laboratory findings, post-operative complications and survival. In all the cases where the obstruction site of the FB was visible, the serosa appeared hyperaemic and oedematous to varying degrees. Removal of the FBs was accomplished
mainly by small colon enterotomy (n = 14), followed by pelvic flexure enterotomy (n = 8), right dorsal colon enterotomy (n = 5), high enema (n = 5) and small colon resection and anastomosis (n = 1). The FBs consisted predominantly of pieces of twine in 22 cases (P<0.0001). Fragments of nylon were seen in six cases and a hair pin was found in one horse. In 27 cases, the FB was embedded in an irregular, soft, partially mineralised mass surrounded with faecal material (Fig 2). Two horses had FBs which had undergone a uniform hardening with mineral deposition, which gave the FBs the appearance and texture of an irregular enterolith (Fig 3). Additional findings during surgery included large colon impaction (n = 14) and right dorsal displacement of the large colon (n = 1). Pelvic flexure enterotomy was performed in 27 horses as a
means to remove the FB or evacuate the large colon. Mean surgical time was 199 min (median: 180 min, range: 120– 320 min). Time of surgery did not differ significantly between the different techniques used to remove the FBs. Two mares were subjected to euthanasia during surgery.
One was euthanised due to gross contamination of the abdomen during attempts to remove the FB from the aboral right dorsal colon. The second mare was subjected to euthanasia during surgery due to severe and extensive damage to the small colon as a result of the FB. Post-operatively, horses were continued with i.v. fluid
therapy for a mean duration of 2.5 days. Penicillin G sodium (22,000 U/kg bwt, i.v., every 6 h) and gentamicin (6.6 mg/ kg bwt, i.v., once a day) were given for a mean duration of
Fig 2: Representative image of the foreign body found in most cases. The foreign body was embedded in an irregular, soft, partially mineralised mass surrounded by faecal material.
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