This article was written by Three Counties Equine Hospital & is reproduced with their permission. www.tceh.co.uk
What is Colic?
Not only does the mere mention of the word “colic” send many owners into immediate panic, it can also be one of the most challenging of conditions for vets to diagnose and treat. Colic isn’t a specific disease but more a collection of clinical signs that have numerous causes and result from gastrointestinal pain. Although it is one of the most common causes of death in healthy adult horses, it is important to remember that approximately 90% of cases resolve with medical treatment.
The design of the horse’s gastrointestinal tract is complex and makes it vulnerable to certain types of colic. The wide and narrow intestines, the tight turns and the relatively minimal anchoring of the gut (thus allowing it to twist, flip and shift in the abdominal cavity) all have the potential to contribute to colic. However, most causes of colic are unknown.
What are the signs of colic?
Signs of colic are very variable and will also depend on the individual horse. They can be as little as a change in behaviour or may be uncontrollable rolling.
The following are some signs:
• Lying down more than usual
• Standing stretched out and posturing to urinate
• Turning the head towards the flank
• Repeatedly curling the upper lip
• Pawing the ground and intermittent pacing
• Sweating up
• Kicking at the belly
What are the types of colic?
- Gas Colic – Gas may build up in the intestines, especially the large intestine and caecum. The gas stretches the intestine, causing pain. Gas colic normally resolves fairly easily with treatment. It is essential to make sure there is no underlying reason for the problem.
- Spasmodic Colic – This is due to increased intestinal contractions, which can cause pain. These cases also generally respond well to treatment.
- Impaction Colic – Impaction colic is similar to constipation in humans and is particularly common in colder weather when horses tend to drink less and their diets move from grass (with a high moisture content) to hay (with a low moisture content). Impactions commonly occur in the large intestine, which has numerous bends. However, impactions can also be caused by parasites, sand (common in areas where the soil is naturally sandy) or enteroliths (stony, mineral deposits that form in the gut and can cause an obstruction when they grow). Intravenous fluid therapy, liquid paraffin and pain killers usually allow these impactions to pass through, but some severe ones may require surgical treatment.
- ‘Twisted gut’ – A piece of the intestine twists around itself. Twisted guts are very serious, and the intestines will stop working and fluid will build up in the intestines found before the twist (blockage). Most of these cases require surgical correction.
- Gastric Distension/Rupture – The horse is unable to vomit, so if it gorges itself on grain or dried beet pulp (which swells once it is in the stomach) there may be serious consequences. In severe cases, the stomach may burst, which is fatal.
- ‘Unknown’ – In many cases of colic it is impossible to determine the reason for the pain. Symptomatic treatment and close monitoring are often enough to treat the problem.
How do I know if my horse has surgical colic?
When a horse does not respond to medical treatment of colic and continues to show signs of pain, it may be necessary to consider surgical correction of the problem. Although some cases are obvious surgical candidates, others are less clear-cut and thus require various diagnostic assessments to make the decision. These investigations may include rectal examination, ultrasonography, passage of a nasogastric tube (a flexible plastic tube from the nostril into the horse’s stomach) and analysis of blood samples and peritoneal fluid (abdominal fluid that the gastrointestinal tract is bathed in). When surgery is required, the horse is anaesthetised and positioned on its back, and the surgical incision is made on the ventral midline (under the abdomen). Once the abdominal cavity is entered, portions of the intestine are then examined to determine the definitive cause of the colic. Correction may involve repositioning a displaced portion of intestine, removing an obstruction, or resecting devitalized intestine.
What care is required after surgery?
After recovery from surgery horses are usually placed on intravenous fluids, antimicrobials and analgesics (pain killers) and hospitalised for 5-7 days prior to going home. Each horse must be handled individually, and its treatment needs are based on its response to surgery and the development of complications. Possible complications include the onset of laminitis, infection of the surgery site, hernia formation, thrombophlebitis (infection of the vein where the catheter was placed) and ileus (reduced motility of the gastrointestinal tract). Horses that have undergone colic surgery require 6 weeks of box rest prior to turnout into a small paddock and it is advised not to return to exercise before three months in order to allow the abdominal wall to heal and strengthen sufficiently.
What is the prognosis and are there any factors that predispose my horse to colic?
Survival of horses with colic is difficult to summarize because it is influenced by many factors but reports indicate over 85% survival for medically managed colic. The long term survival for horses undergoing surgery for colic ranges from 34-90% depending on the age of the horse, the type of surgery and the exact location of the gastrointestinal tract involved.
Because many causes of colic are unknown, it is often difficult to prevent recurrences but several risk factors have been identified. Although there is no clear evidence that any age, sex or breed predispose to colic generally, this can vary with type of lesion: for example, older horses have a higher risk of strangulating lipoma (fatty tumour) than younger horses. Crib biting has been associated with various types of colic, as has a lack of regular deworming and an absence of regular dental examinations. A change in diet, exercise, stabling or significant change in weather have also been identified as risk factors.