Equine Colic: How to Make the Decision for Surgery

Determining the need for surgery in a horse with colic is usually an emergency. The decision is best based on a diagnosis, however, a specific diagnosis is not always possible and use of clinical signs is often necessary to make the decision. The specific signs most helpful in indicating surgery are presented in Table 1. However, a thorough examination must be performed prior to deciding to refer a horse for surgery since each clinical sign by itself has inherent error when used alone to make the decision. There are circumstances when the diagnosis cannot be made and there are no definitive rectal examination findings to help in making the decision. However, unrelenting pain, which does not respond to analgesics, or recurring pain after analgesic administration are indications for surgery if no diagnosis has been made.

There are no strict guidelines or list of parameters that decide the need for surgery as there are varying degrees of severity, and a range of clinical signs for the diseases and every horse can respond in a different way. Therefore, every case should be judged on its own merits based on history and a thorough examination. In certain cases, a rapid decision can be made if a diagnosis is made from the clinical signs. The history and presentation may indicate immediate surgical intervention without processing all the information from a complete examination for colic. Pain by itself if persistent or recurrent is an indication for surgery.1 This is particularly true if there is no response to analgesic administration. For example a broodmare presented 5 days after foaling with an acute history of severe abdominal pain, severe large colon distension and clinical signs of endotoxemia indicative of a large colon volvulus is in need of immediate surgery based on a presumptive diagnosis.

With the advent of potent analgesics, veterinarians have used the response to treatment to effectively determine which horse needs surgery. This is logical and if used with other physical signs, monitoring pain after treatment is highly successful in determining which horses will need surgery prior to other indicators. The timing of the response still needs refinement, but most veterinarians have determined the response time for the analgesics they use for most cases of colic. Horses that have constant pain, particularly after an analgesic has been administered, are significantly more likely to need surgery.1,i Horses that have return of pain or those requiring a second administration or multiple administrations of an analgesic are also significantly more likely to need surgery (Table 2).1,2 The key is monitoring signs and adjusting one’s tolerance for any recurrence of pain, as horses may show pain after administration of an analgesic, but the signs of colic can be markedly decreased. Though decreased, any recurrence of pain should be considered a failure of resolution of the problem and therefore an indicator of increased odds that surgery is necessary. Return of pain in horses that have a medical problem, [...]