Equine Emergencies
This section contains information on emergencies in horses including colic, non-weight bearing lameness, wounds, eye injuries and foaling emergencies.
Colic
Colic is the word that describes abdominal pain in horses and can be due to many factors because of the complex nature of the horse's digestive system. Unlike humans, horses digest part of their food by fermentation in the huge large intestine. This is because they are herbivores and must digest large amounts of plant matter. Food material enters the stomach from the oesophagus through a one-way valve that prevents food moving back into the oesophagus, hence the reason horses are unable to vomit. From the stomach material passes through another valve and into the small intestine. Here the food material is broken down into they key elements, fat, protein and carbohydrate and is absorbed into the blood. The food material then passes into the large intestine (caecum and large colon) where cellulose is broken down by the bacteria present. The large intestine has to fold within the abdomen due to it's size. One of these folds, the pelvic flexure, is a common site for impactions to form. From the large intestine waste material is passed to the rectum and excreted. Waves of muscle contractions, peristalsis, allow the flow of food material through the digestive system. A horse that is showing signs of colic should be seen as an emergency and veterinary advice sought immediately.
Clinical signs
Horses with colic can show a variety of signs they may kick at their belly, circle, look at their flanks, roll, lie down sweat up and be off their food. While waiting for the vet to arrive horses should have any food taken away and just left with water. If the facilities are available the horse should brought into a stable with a deep bed and banked sides. It can be useful to walk the horses around, however, this should be done on a soft surface e.g.a ménage, as the horse may roll and injure itself further.
Diagnosis
The clinical signs are usually enough to diagnose that a horse has colic, however, a thorough colic examination by the attending vet can provide vital information about the severity and potential causes of the colic. The key parts of a vet's assessment of a horse with colic are listed below.
- Degree of Pain: An assessment of the severity of the colic can be useful, however, different horses will behave differently to similar degrees of pain.
- Pulse rate: The normal resting heart rate for a horse is between 32 and 48 beats per minute, stressed animals or those that have been rolling will have a higher heart rate. If some intestine has become damaged toxins can enter the blood stream causing the heart rate to increase significantly.
- Mucus membrane colour: Horses will normally have pale pink mucous membranes, in some colic patients this can change due to problems with blood flow caused by toxin release.
- Gut sounds: A horse's gut sounds can be heard easily using a stethoscope. In some cases, spasmodic colic or enteritis, these sounds can be increased or in others, obstructions, be reduced or absent.
- Passing a stomach tube: A tube can be passed down the nasal passage, through the oesophagus and into the stomach. In horses with an obstruction fluid can build up in the stomach, as they cannot vomit. When the stomach tube is passed this fluid can be released, as well as preventing the stomach from rupturing this is a very good indicator that an obstruction is present.
- Rectal exam: Some abnormalities can be felt by the vet by palpating the abdominal contents via the rectum.
- Blood sample: A blood sample can be used to measure blood concentration and protein levels. This can assess the degree of dehydration and, therefore, determine whether iv fluids are required.
- Peritoneal tap: A needle can be placed into the abdominal cavity from the underside of the horse and a sample of the fluid retrieved and then analysed. Normal peritoneal fluid should be pale yellow in colour in some cases the fluid can be cloudy, red-tinged or even black. The nature of this fluid can give vital clues as to what is occurring within the abdomen.
- Ultrasound examination: Some abnormalities can be seen by scanning the abdomen, such as distended loops of small intestine.
The attending vet must build up a picture using some or all of the above techniques to assess the severity and likely causes. Most horses don't show any major abnormalities and are treated with pain killers and/or sedation and the owner left to monitor them. Others are deemed far more severe, i.e. high heart rate, severe pain that responds poorly to pain killers, no gut sounds, abnormal on rectal exam, etc, and require further evaluation and often emergency surgery. It is at this point that many horses must be referred to a hospital with the necessary facilities. The key thing to understand with colic is that in most cases a diagnosis as to the cause of the pain is never reached unless surgery is performed or an obvious impaction or displacement felt rectally. The vet is, therefore, assessing which causes are most likely after a careful examination, and treating it accordingly. Approximately 80% of the colic's I see appear to have no obvious cause and no diagnosis is reached, yet the animal has no major irregularities on clinical exam, apart from abdominal pain, and settles very well after pain killers, sedation or anti-spasmodic drugs.
Risk Factors
The risk factors for colic are recent feed changes, lack of access to water and grass, and worms. Horses should be wormed regularly, see section on worming, and should have all feed changed made gradually.
Non-weight bearing lameness
Horses that suddenly go very lame will often have obvious areas that appear to be the problem, however, in many cases the cause may not be apparent. In any of these cases a vet should be contacted immediately and the horse kept still and calm in the mean time. The attending vet should examine the animal carefully to find potential problem area's and treat them accordingly. When the cause is unknown or more information is required, x-rays, bone scanning and ultrasound scanning, may all be used. In some cases nerve blocks can be used to help find the source of pain. The conditions below are the most common causes for animals to be severely lame.
Fractures
Fractures of any long bone will usually cause a sudden, severe lameness, usually non-weight bearing, and have severe pain and swelling on palpation. A suspected fracture is an emergency and a veterinary surgeon should be called before attempts are made to move the animal. A large bandage with a splint should be applied to support the limb. Other fractures, such as fractures of the pedal bone, splint bones or small bones of the hock and knee, are not often as much of an emergency, however, a prompt diagnosis can aid in recovery by allowing treatment to be initiated, i.e. removing any bone fragments surgically.
Diagnosis
X-rays are taken to assess treatment options, although, in many instances examination of the animal can provide enough information as to whether the fracture is treatable or not. Occasionally a bone scan may be required to find the fracture.
Treatment
Fractures of a long bone in the horse generally carry a poor prognosis. Certain fractures can be treated surgically, however, euthanasia on humane grounds must be considered for all long bone fractures. The treatment options and prognosis for other fractures are better for other fractures, however, each case must be treated individually. Surgery is usually required for fractures of the small bones of the hock or knee and is often successful in returning the horse to soundness. Pedal bone fractures require months of box rest.
Foot abscess (pus in the foot)
A foot abscess can be caused by a penetrating wound (nailprick), secondary infection of bruised tissue or as a sequel to a crack in the white line and is the most common cause of lameness in horses. The pain is due to the rigid structure of a horse's foot. As the infection progresses pressure is built up in the foot as there is nowhere for the abscess to expand. The typical scenario is for a mild lameness to develop quickly, can be hours to days, until the animal is reluctant to bear any weight on the limb.
Diagnosis
The affected foot will have a bounding digital pulse, the presence of heat and pain when pressure is applied with hoof testers.
Treatment
Ideally the abscess should be drained from the sole using hoof knives. The foot should then be dressed to keep the area clean and horse kept on box rest until the lameness has resolved and the sole has hardened. Poultices only serve to soften the horn and are best avoided unless the abscess cannot be drained. Tetanus infection can occur as a sequel to a foot abscess, therefore, tetanus antitioxin should be given. To aid in the prevention of foot abscesses horses should have their feet regularly trimmed.
Puncture wounds to the sole
Penetrating wounds will usually cause an immediate severe lameness and should be fully investigated. Although the penetration may only be superficial, commonly causing an abscess, deeper wounds can damage many other structures. These include the pedal bone, digital cushion, navicular bone, navicular bursa, deep digital flexor tendon, digital sheath or coffin joint. For this reason puncture wounds should be investigated thoroughly. The wound should be probed and, in many cases, radiographs taken to assess which structures are involved. Treatment depends on the structures damaged by the penetration.
Nail bind
Nail bind is direct injury to the sensitive laminae by a shoe nail. Usually horses will become lame a few days after shoeing, although some can be lame immediately. The injured area can sometimes become infected and cause a foot abscess.
Treatment
Sometimes removal of the offending nail is all that is required, however, in many instances the entire shoe is removed.
Joint infection (septic arthritis)
A joint may become infected due to penetration of the joint or, less commonly, by the spread of infection within the blood.
Signs
Horses will show a very severe, non-weight bearing lameness with a hot, painful swelling of the joint. In some cases joint fluid continues to drain through the wound preventing the build up of fluid within the joint and, therefore, the lameness may not be as severe.
Diagnosis
A diagnosis is usually reached by analyzing a sample of synovial fluid from the joint. X-rays may show aggressive damage to the joint.
Treatment
The best treatment is to flush the joint surgically, usually via arthroscopy (key hole surgey), combined with antibiotic therapy. The affected joint should be bandaged tightly and the horse placed on box rest. Treatment is best carried out a soon as possible to increase the chances of getting the infection under control and reducing the risk of further problems, e.g. degenerative joint disease (DJD). If DJD is considered likely, medication may be required to prevent the onset of the condition. Luxation (dislocation) of the superficial flexor tendon The superficial flexor tendon is held onto the point of the hock by strong ligament-like attachments. Luxation (dislocation) of the tendon occurs when one of the attachments ruptures. This usually occurs due to trauma.
Signs
The animal will show a very sudden severe lameness with swelling at the point of the hock. Once this initial period is over the tendon can be seen occasionally slipping off the hock, each time causing distress to the animal. Eventually the tendon adapts a new position to the side of the point of the hock which can be easily seen.
Treatment
The condition is initially treated with rest and anti-inflammatory drugs such as phenylbutazone ('bute') and bandaging of the limb. After this period surgical treatment can be attempted or the animal simply kept on box rest until the tendon settles in a new position. Most horses usually require at least a year off work and not all of them become sound.
Wounds
Wounds and lacerations are common in horses. Any bleeding wound should have a pressure bandage applied immediately and a vet contacted. If the blood is seeping through this layer of bandage keep applying more on top as reducing the bleeding at this early stage is vital. Those that are not bleeding should be clipped and cleansed, however, try to avoid applying lotions and ointments at this stage. A fresh wound that is not under too much tension can often be stitched, if you are unsure whether or not your horse's wound can be stitched contact your vet and describe the wound. The attending vet will examine the wound carefully, this should involve probing the wound to assess it's depth, and assess what structures may be involved. The vast majority of wounds simply involve only the skin, however, a main area of concern is any joint, tendon sheath or bursa. Early recognition that one of these structures has been penetrated is essential as evidence from numerous studies shows that surgically flushing these cavities within 24 hours greatly increases the chances of a successful outcome. Once the wounds have been assessed they can be treated accordingly. Wounds that only involve the skin, which may be stitched, should be well cleansed and bandaged and the horse placed on antibiotics to prevent infection. An animal with a small wound away from any joints that is completely sound does not necessarily provide veterinary attention providing it is well cleansed and monitored. If there are any signs of swelling or lameness a vet should be contacted. Some wounds may develop proud fresh, excessive granulation tissue. This usually occurs on the limbs and I caused by either too much movement or infection. These cases should be assessed by a vet who may trim back the proud flesh and/or apply steroid cream to the area. The wounds should then be bandaged tightly.
Eye injuries
Injuries to the eyes are always an emergency due to the potential risk of the animal losing their sight. Most of these injuries are traumatic and include lacerations of the cornea, penetration injuries, blows to the eye causing detachment of the retina and wounds around the eye. The horse should be placed in a dark environment until the vet arrives and kept calm. A careful examination must be carried out to assess exactly which structures have been damaged before treatment can be initiated. Initial treatment is aimed at reducing the pain and inflammation within the eye. Prompt surgical treatment may be required, however, others need only topical treatments, sometimes have to be given every hour. Some horses are required to have the affected eye removed as it is causing too much pain to the animal and is beyond repair. Although some changes to the horse's routine and management are needed animals with only one eye normally cope remarkably well.
Foaling emergencies
Problems during foaling may be caused by an overlarge foal or the foal being presented incorrectly, however, thankfully vast proportion of mares will foal on their own without any problems. Problems foaling are most commonly caused by mal-presentation of the foal, however, the other causes exist. These are abnormalities of the pelvis, the presence of twins, failing to lie down for foaling, weak uterine contractions and premature separation of the allantochorion. A vet must be contacted immediately if you feel that a mare is having difficulty foaling. In the mean time you should attempt to keep the mare up and walking round the box. The attending vet should carefully examine the mare and perform a vaginal exam to assess how the foal is presented. Once this is known the foal can be manipulated into the correct position and carefully delivered manually. In rare cases mares require a caesarean section, delivery under general anaesthetia or an embyotomy (in cases where the foal is dead).