Colic

By Richard Knight, BVetMed MRCVS from The Peter Fenton Veterinary Practice

Colic is well recognised by the majority of horse owners with many having experience of their own horse or a friends having been affected. Colic is simply the clinical signs shown by horses in response to abdominal pain and not an actual disease as there are many different reasons that cause similar clinical signs. The most readily recognised signs include inappetance, kicking at the abdomen, flank watching, rolling, reduced amount of droppings and increased respiratory rate. When your horse is examined with colic it will also be assessed for heart rate, gut sounds and an internal examination will be performed, these give a great deal of information about the cause and severity of the condition. We can then broadly classify the diseases as either medical or surgical, most medical colics will be successfully treated on the yard whereas all surgical colics will need immediate hospital treatment and even then carry a more cautious prognosis.

In summary EVERY colic needs to be considered surgical until proven otherwise. The prognosis of horses with surgical colic depends enormously on the speed at which they get to a referral hospital, so DON’T WAIT!!

Acutely painful eyes

Any disease process in the eye should be considered an emergency. The equine eye is a highly specialised but very delicate structure and diseases require proper diagnosis, followed by appropriate treatment. As such, no attempt should be made to “self-diagnose” ocular disease.

ColicEyeOcular disease can manifest itself in a relatively limited number of ways which can sometimes make diagnosis challenging, as many ocular disease processes will appear outwardly similar.

Clinical signs of ocular disease include ocular discharge, pupillary constriction, excessive tear production (epiphora) to closed painful eyes (blepharospasm). It is important to remember that not every runny eye is simply conjunctivitis!!

The most common cause of a painful, discharging eye is a Corneal Ulcer. The cornea is the outer layer of the eye through which light passes to reach the retina, it is therefore required to be transparent and unscarred to allow complete light transmission.

Corneal ulcers occur when the surface of the cornea is damage by external trauma, commonly thorns or grit becoming stuck in the eye. While the cornea is a pretty robust tissue; able to heal superficial damage quickly and effectively, deeper trauma will result in ulcer formation.

Commonly the cornea around the ulcer will be slightly cloudy. This is an indication of corneal injury or inflammation and should never be ignored.

Corneal ulcers are diagnosed using a specialist stain called Fluorescein. This dye is orange until it comes into contact with tear film, or damaged corneal cells, when it becomes luminous green. Putting a few drops of Fluorescein into injured eyes allows the location and size of suspected ulcers to be assessed.

Another cause of acute ocular pain is Equine Recurrent Uveitis (ERU). ERU, also known as Moon Blindness, is an inflammatory condition which affects the Iris, Ciliary body and Choroid.

ERU is not fully understood, and the exact cause of the condition is still unknown. Numerous theories have been proposed, from viral or bacterial infections to auto-immune disease, but none of these have been proven.

Clinical signs of ERU vary, but classically the affected eye will have a constricted pupil, corneal oedema and cloudy protein deposits in the Aqueous Humour (Aqueous Flare).

ERU is a painful, serious disease. It can result in the permanent blindness of affected horses, meaning treatment needs to be implemented quickly to reduce in the inflammation within the eye. Treatment usually includes topical anti-inflammatory steroid drops, atropine drops to dilate the pupil, and sometimes systemic pain relief.

Unfortunately horses that are diagnosed with ERU are very likely to have further episodes of the disease, and the overall prognosis is guarded to poor with horses commonly developing cataracts and damage irises.

Respiratory Distress

Acute respiratory distress is a veterinary emergency and horse’s suspect of suffering from such an episode should be examined immediately.

There are several possible causes, including laryngeal paralysis, a foreign body occluding the nasal passages, acute recurrent airway obstruction or a severe allergic response.

Clinical signs of acute respiratory distress include a rapid shallow respiration rate, sweating, flared nostrils, an extended neck, pale or blue gums and abdominal effort while breathing.

Respiratory distress occurs when the effort of breathing is suddenly increased, either by a physical blockage, or narrowing of the airways. It can be fatal.

If the respiratory distress is very severe it may be necessary for your vet to place a tracheostomy tube into the trachea, to bypass the nasal cavity and larynx.

In less severe cases, or those suspected to be caused by allergy, steroids are commonly used to reduce the inflammation of the airways as well as drugs to dilate the airways, reducing the resistance to inspiration.

Continuing treatment will depend on the cause of the respiratory distress, but careful management is essential to prevent further episodes.

Diarrhoea

Diarrhoea is a medical emergency in horses or any age and is most often caused by Enteritis (inflammation of the intestines). Enteritis can result from bacterial infection (including Salmonella, E.Coli), high worm burdens or a rapid change in diet.

Diarrhoea causes horses to lose vast quantities of fluid and electrolytes (salts such as Sodium and Potassium).

Losing fluids and electrolytes has catastrophic effects on the body, including severe dehydration, heart  arrhythmias, muscle fasciculatios (tremors).

Even more seriously horses with diarrhoea can become Endotoxaemic. This is caused when harmful bacterial toxins are released from the inflamed intestines into the blood stream. These toxins cause a huge inflammatory reaction and can lead the horse to developing shock or circulatory collapse.

Endotoxaemia will produce deep red/purple gums, ANY horse seen with such gum colour needs to be seen immediately.

Treatments will depend on the severity of the clinical signs, and the degree of dehydration.

If horses are severely debilitated they will need to be placed on intravenous fluids to replace their lost blood fluid volume. Oral fluids, via stomach tube, may also be used.

Providing intravenous fluids also allows the lost electrolytes to be replaced, but the exact amount required will need to be determined through blood samples.

Horses also need to be provided with large quantities of water for them to drink, but if a horse becomes sick enough not to want to drink their management becomes a crisis.

If horses are showing signs of endotoxaemia potent anti-inflammatory drugs can be used to counteract the effect of the endotoxin.

If the worming history is unclear, or if worms are suspected to be implicated a wormer should be given. Your vet should be contacted before purchasing any wormer, as not all worms are killed by every wormer.

In addition, your vet may decide to use anti-inflammatory drugs at the same time as the wormer to reduce the effect of a large numbers of worms being killed at once.

If an infectious cause of the diarrhoea is suspected, such as Salmonella, every care needs to be taken to prevent further spread to other horses or humans. Such horses need to be put in isolation and people need to take thorough personal hygiene precautions.

Not all horses with bacterial enteritis require antibiotics, and whether or not your vet decides to use them will depend on the severity of the clinical signs and the suspected causative agent.

Author: Features Editor

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