Colic

Introduction

Colic is the number one killer of horses. Fortunately, most cases of colic are mild and resolve with simple medical treatment or no specific treatment at all. In fact, less than 10% of all colic cases are severe enough to require surgery or to lead to the death of the horse. Nevertheless, every case of colic should be taken seriously, since it can be difficult to differentiate a mild case from a potentially serious one in the early stages.

‘Colic’ is not a disease in itself; it is merely a symptom of disease, indicating pain in the abdomen (belly). There are many different conditions that can cause a horse to show signs of abdominal pain. Most of these involve the digestive system, i.e. the stomach or intestines, although colic can also be related to other body systems such as the reproductive tract.

Equine colic

Is my horse showing colic?

Horses show abdominal pain in many different ways. Some signs, such as curling the upper lip, are subtle and easily overlooked, whereas other signs, such as repeated rolling or violent thrashing, are hard to mistake. The severity of the clinical signs does not always correlate with the severity of the underlying disease process, particularly in the early stages.

Common signs of colic include:

Turning the head towards the flank (also known as ‘flank watching’)
Pawing the ground
Kicking or biting at the belly
Stretching out as if to urinate, without passing any urine (sometimes referred to as a ‘trestle table stance’)
Lying down and getting up repeatedly
Repeated rolling, often accompanied by grunting sounds
Sitting in a dog-like position, or lying on the back (above left)
Holding the head in an unusual posture, e.g. with the neck stretched out and the head rotated to one side
Lack of interest in food; either not finishing a meal or complete disinterest
Less frequent or absent bowel movements
Less obvious or absent digestive sounds
Sweating in the absence of physical activity or hot environmental temperatures
Rapid breathing and/or flared nostrils
Increased pulse rate (greater than 50 beats per minute)
Depression
Lip curling in the absence of sexual interest
Grinding the teeth

An individual horse may show any one or several of these signs. Seeing any of these signs, particularly if they are persistent, should prompt you to monitor the individual closely. In more serious conditions the signs often persist or worsen with time and fail to respond to pain medication, whereas in milder cases the signs may only be intermittent and may disappear after a short time with no treatment. However, do not rely on the severity of the signs as a strict predictor of the likely severity of the underlying disease process.

What action should I take?

Some cases of colic resolve without veterinary attention, however, a significant percentage of horses ultimately require medical treatment. The most critical factor in the successful treatment of colic is time, particularly if the horse requires emergency surgery.

If you suspect your horse is suffering from colic, we recommend you take the following action:

Call you Veterinary Surgeon immediately. They may decide it is not necessary to see your horse immediately, but leave the decision to them. Be prepared to provide them with as much information as possible:
- Specific signs that indicate colic
- Pulse or heart rate (beats per minute) measured over heart just behind left elbow or over an artery (on underside of jaw or back of fetlock)
- Breaths per minute
- Rectal temperature
- Gum colour (white, pale pink, dark pink red, blue-purple (below), grey)
- Digestive sounds (if any)
- Bowel movements - colour, consistency, frequency
- Any changes in recent management
- Medical history, especially history of deworming
- Breeding history and/or pregnancy status
- Insurance status

NB: Do not worry, or delay calling your Veterinary Surgeon if you cannot provide all of the above information.

Remove food, but leave some water.
If possible, move the horse to an enclosure (stall or small paddock) so that they may be observed more closely.
If possible, ensure adequate lighting so that the horse may be examined properly.
Let the horse rest if it wants to stand or lie down quietly. Walk the horse around if it is continually rolling or in danger of hurting itself. DO NOT tire the horse with relentless walking. DO NOT risk injury to yourself and others by handling a horse that is showing violent colic signs.
Follow the advice of your Veterinary Surgeon. They will advise as to the appropriate course of action.
DO NOT administer any drugs to the horse, unless advised to do so by your Veterinary Surgeon, since these may mask serious problems. They may make the task of making an accurate diagnosis more difficult and time-consuming.

Is there anything I should avoid?

DO NOT pass any kind of tube into the horse’s stomach. Severe damage to the upper airway and oesophagus can result from inappropriate passage of a stomach tube. In addition, if the tube is incorrectly placed in the windpipe any liquid delivered via the tube will end up in the lung, leading to fatal consequences.

DO NOT attempt to give the horse anything, especially liquids, by mouth. Horses in pain will often not swallow these substances, and they may be inhaled.

DO NOT insert anything into the horse’s rectum, other than a thermometer. The rectum can be easily damaged and rectal tears can be rapidly fatal. Attempts to relieve intestinal blockages via rectal manipulation are rarely successful.

DO NOT give any intravenous injections. Even if you have experience giving injections, a painful horse is a more difficult target and all intravenous injections carry risk.

What will my Veterinary Surgeon do?

If your Veterinary Surgeon decides that a veterinary examination is necessary, they will employ some or all of the following techniques to devise an appropriate plan of action (those indicated by a asterisk are optional, with the decision to perform them being based upon results of other tests):

Establish the history (especially focusing on changes in management, feeding, de-worming, other medical problems and current treatments, vaccinations)
Evaluation of the horse’s behaviour
Physical examination
Rectal palpation*
Passage of a naso-gastric tube* (see image)
Collection of fluid from the abdominal cavity (peritoneal or 'belly' tap*)
Blood tests*
Evaluation of response to treatment

Based upon the findings of their examination, your Veterinary Surgeon may opt for medical management at your yard or they may elect to refer your horse for further evaluation and treatment at our hospital.In the case of referral, your Veterinary Surgeon will contact our hospital to discuss their initial findings so that we can be ready to receive your horse.

What will happen at the Royal Veterinary College Equine Referral Hospital?

A team of staff and students will be ready for your arrival, and your horse will be examined in a similar fashion as described previously. You will be asked to sign a form giving us consent to carry our examinations and treatments as necessary. Depending upon the severity of the signs, a more or less lengthy history may be taken. You may feel that you are repeating the history several times to different individuals; however, this is essential since it means that nothing in the horse’s history will be overlooked.

We will often repeat some or all of the tests already performed at your yard, since findings can change quickly with time, and these changes can be important to making an accurate diagnosis. In addition, we will perform an abdominal ultrasound examination, which has been shown to be extremely helpful in decision-making, particularly in cases of small intestinal obstruction (see below).

An intravenous catheter will usually be placed in the jugular vein and often fluids will be administered as soon as possible to resuscitate the horse as necessary.

When we have completed our evaluation we will discuss the treatment options with you. The key decision is often whether the horse can be managed medically or requires surgical treatment. This decision will be made as promptly as possible, and involves classifying the type of colic.

Classification of colic

Intestinal dysfunction

This is the most common category. This category includes spasmodic colic, which results from altered motility; gas distension; impactions; decreased motility (ileus). These types of problems often respond to medical treatment.

Intestinal accident

This group of disorders occurs much less frequently. These include intestinal displacements, twists (torsion and volvulus) and entrapment of intestine (i.e. through internal or external hernias). The degree of severity and choice of treatment in this group is determined by whether or not the blood supply to the bowel has been compromised. If the blood supply has been compromised, these conditions require emergency surgery but if not, some can still be treated medically.

Inflammation or ulceration

This group includes gastritis (stomach), enteritis (small intestine) and colitis (large intestine). Stress, medications, infection and parasites can all play a role. These conditions can most often be treated medically.

Grass Sickness is a unique condition seen in the UK and some other isolated regions of Europe. The cause is unknown but the clinical signs result from destruction of nerves within the wall of the digestive tract. Diagnosis of grass sickness can only be made by biopsy of the small intestine, necessitating surgical treatment. Confirmed cases have a poor prognosis for survival.

What treatments may be administered?

Pain relievers or sedatives may be used to control pain while intestinal function normalises, further tests are performed or other treatments are administered.
Fluid therapy helps to correct dehydration and to soften intestinal contents. This may be administered either by stomach tube or via an intravenous catheter, most often in the jugular vein.
Laxatives such as mineral oil administered via stomach tube.
Enemas, particularly in young foals suspected of having meconium retention.
Surgery under general anaesthesia.

What if my horse needs surgery?

Colic surgery is performed under general anaesthesia. Based upon our examination findings we should know what type of surgery will be required. Your horse will be induced under anaesthesia by injection in a controlled, padded environment by our experienced and dedicated anaesthesia staff . The horse will have a tube placed in the trachea to allow ventilation with oxygen and anaesthetic drugs. A full suite of monitoring equipment will be used in order to make your horse’s anaesthetic as safe as possible, including direct blood pressure measurement, ECG (measuring electrical activity of the heart), blood gas analysis (measuring the levels of oxygen and other gases in the blood) and capnography (measuring the concentration of carbon dioxide in the air expired by the horse). Generally, an incision is made in the midline of the abdomen from the navel forwards. This allows as much of the abdomen as possible to be explored. When the cause of the colic has been identified and corrected, the incision is sutured closed. Your horse will be recovered from anaesthesia under very controlled conditions. We are able to control the noise levels, ambient light levels and temperature of our padded recovery rooms. Your horse will be monitored closely, which is aided by video cameras and screens positioned directly outside the stalls. We are able to assist and stabilise all horses during the recovery process, minimising the likelihood of complications. Unfortunately, when an adult horse weighing 500kg recovers from anaesthesia the risk of complications cannot be eliminated entirely, and a small risk of muscle or bone injury remains.

Will there be post-operative complications?

Although we do everything possible to minimise the risks, abdominal surgery in the horse is a serious procedure. Since these individuals are often very sick, some complications are possible. Post operative pain, wound infection, infection at the catheter site in the jugular vein, peritonitis, adhesions, laminitis and hernia formation are all possibilities. The vast majority of such complications can be readily managed, although they may delay discharge from the hospital.

Summary

The key to minimising the incidence of colic is good management. The key to minimising the impact of colic and increasing the chances of a good outcome is early and appropriate treatment. Treat every episode of colic as potentially serious and involve your Veterinary Surgeon from the outset.