from the Vet Corner Archives

Part of Horse Previews Magazine website. Posted on 07/09/2001; 2:00:00PM.

Veterinary Corner 07/01: Rectal Tears in Horses

by Frosty Franklin, DVM
Edgecliff Equine Hospital
S. 1322 Park Road, Spokane, WA 99212 * 509/924-6069

Rectal palpation and examination of the horse is an important diagnostic procedure in evaluating urogenital organs as in a pregnancy exam and the digestive system as in a colic exam. Many horse owners are unaware that there are risks performing a rectal exam. Rectal tears are rare but they do occur. They occur when experienced equine practitioners as well as new graduates conduct these procedures. Almost every equine veterinarian can expect to be directly or indirectly involved with a rectal tear. It has been suggested that rectal palpation alone cannot cause a rectal tear, rather tears usually result from contraction of the rectal wall around the examiner's forearm and rarely by penetration of the fingertips of the examiner during palpation. As evidence, most rectal tears occur on the dorsal, or upper wall of the rectum, not the ventral aspect of the rectum where the palpating fingers are evaluating various anatomical structures.

Arabian horses, stallions and young horses (one to five years of age) are over represented in studies of rectal tears. According to data from the AVMA Professional Liability Insurance Trust for the period of 1979 to 1994, 31.7% of reported rectal injuries were in Arabian horses, 26.8% were in American Quarter Horses, and 18.5% were in Thoroughbreds. In some cases it may be advisable to avoid a rectal examination. If the person handling the horse is not proficient, the facilities are not fitting or the temperament of the horse is not suitable, the risks of a rectal tear are increased. It is the responsibility of the veterinarian to ensure the horse is restrained adequately. In our practice we sedate many horses for rectal examination. We prefer stocks that limit movement of the horse and protect the examiner and handler.

Rectal tears are graded or classified according to the layers of the rectal wall penetrated. A Grade I tear involves just the mucosa and submucosa. Only the muscular layer is disrupted with a Grade II tear. In Grade III tears only the serosa is intact, which means the mucosa, submucosa and muscular layers are torn. Grade IV tears are full thickness of the rectal wall and communicate with the abdominal cavity. In a recent retrospective study of 85 rectal tears treated at the Veterinary Medical Center at Texas A & M University, 14 of 14 horses with Grade I rectal tears were discharged from the hospital alive. They received a combination of antibiotics, stool softeners and Banamine. Two of three horses were discharged alive with no treatment of Grade II rectal tears. The third horse was euthanized because of development of chronic impactions of the pocket formed by the Grade II rectal tear that involved three-quarters of the circumference of the rectum. Thirty-six horses had Grade III rectal tears. Eleven (31%) of these horses did not survive despite a variety of surgical treatments, that included temporary indwelling rectal liners, loop colostomies, end colostomies and direct suturing. There were 31 horses presented with Grade IV (full thickness) rectal tears. Twenty-five horses were subjected to euthanasia at presentation due to extensive fecal contamination of the abdominal cavity. Surgical treatment was attempted in six cases. Two of six of the horses were discharged alive. When blood is found on the rectal sleeve, the extent of the rectal injury should be determined. The simplest way is to sedate the horse and palpate the rectum without a sleeve. In addition, a transparent 30 cm speculum with smooth edges and a light source can be used to evaluate the rectal tear. Once the rectal tear has been evaluated, the owner/agent and insurance agency (where applicable) must immediately be informed of the findings and the implications for the horse. Then treatment should begin, if that is the owner's decision. Broad-spectrum antibiotics, stool softeners, Banamine and tetanus toxoid should initiate management of rectal tears. Superficial rectal tear cases should be confined and monitored for two days. Temperature, pulse and respiration should be checked two to three times daily. Plenty of water and bran mash should be provided. In cases of severe rectal tears (Grade III and IV) a surgical referral hospital should be contacted. The referral hospital staff will provide further treatment recommendations and a financial estimate to the owner.

In conclusion, it is important that a horse owner understand the serious ramifications of an equine rectal exam. This is a safe procedure and can provide a wealth of information. But the rectal exam is not always innocuous. You need to know!

Happy trails! Frosty

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