Evaluating equine colic: Surgeon's perspective (Proceedings)


Evaluating equine colic: Surgeon's perspective (Proceedings)

Oct 01, 2008

Colic in the horse makes up a large part of equine veterinary practice. The term colic is actually a general term for any causes of abdominal discomfort. The majority of causes of colic stem from abnormalities in the gastrointestinal tract. However, non-gastrointestinal causes also exist, and should not be overlooked. Cases of colic in the adult horse and in horses less than 6 month old should be examined slightly differently, as the most common etiologies are different for these two groups.

Most clinicians are familiar with the classic signs of equine colic, including, pawing, kicking at the abdomen, and rolling. Some other more subtle signs of colic include raising the upper lip repeatedly, backing up into walls, repeatedly extending the penis, and dog sitting. It is important to know what behaviors are abnormal for each individual horse, as some of these signs can occur normally in certain individuals. Each individuals response to pain is different, and there seems to be some breed differences as well. In my experience, Tennessee Walking Horses and Standardbreds seem to be very tough in their response to painful stimuli, whereas Arabians and Warmbloods seem to be not as stoic.

Examining equine colic is like putting a puzzle together to try and arrive at a diagnosis. The pieces to the puzzle include the physical exam findings, rectal exam, laboratory analysis, nasogastric intubation, and abdominal ultrasonography. All of these pieces must be evaluated prior to formulating a treatment plan. The key to generating the necessary working data base from which to make treatment decisions is to have a repeatable examination technique that works for the individual veterinarian. With experience, comparing an affected horse to others with colic can assist in the decision making process.

Historically, veterinarians have lumped the treatment of colic into two broad categories: surgical treatment and medical treatment. However, there is a lot of overlap in these two categories as well as transfer from one category to another. I prefer to examine each animal as an individual, try to arrive at a diagnosis, and initiate treatment. In complicated cases the treatment will need to be modified as the situation changes. I view surgical intervention as part of the medical treatment in certain cases, and as a piece of the diagnostic puzzle in other cases, as it is in most cases an exploratory laparotomy.

Every examination should begin with a thorough history. Important information to obtain includes the duration of the problem, severity and types of clinical signs, treatment prior to the evaluation, and any concurrent problems that the horse may be currently receiving medication for. Also I like to find out if the horse has experienced other episodes similar to this one, as well as the treatment and outcome. In most situations, the time that it takes to get a rectal temperature should be adequate to obtain all of the pertinent history. During this time you should also be able to get a visual impression of the severity of pain that the horse is in now or has been in the past. The presence of abrasions or other wounds around the eyes and head indicates that the horse has experienced severe pain. The experienced practitioner can usually get a good feel for which way a case will go based on the ÒlookÓ of the horse, even prior to laying your hands on the horse.

After I have obtained the history, a thorough physical examination beginning with the vital signs is started. Even in cases of severe abdominal pain, the initial vital signs should be obtained prior to administering any medications, as pharmaceuticals can cause profound alterations in these values. Body temperature determination is critical in all cases of colic, and must be performed prior to rectal examination, as the pneumorectum induced by transrectal palpation will cause an artificially low temperature. Most horses that have a simple gas colic will be normothermic. Additionally, most cases of colic in need of surgical correction will also be normothermic. If a horse has been rolling a lot and the ambient temperature is high, a mild increase in the temperature can be due to exertion. Also, horses coming off of a trailer on a hot day may have an artificially mildly elevated temperature. Horses with inflammatory or infectious conditions of the intestinal tract, such as proximal enteritis or colitis, will often times be febrile. However, if the horse received a non-steroidal anti-inflammatory by the owner prior to your examination, the temperature could be artificially normal. Also, severely dehydrated and shocky animals may be hypothermic, reflecting the severe nature of their problem.