Cian O’Connor and Kilkenny topped the Irish standings in the Olympic showjumping individual final, although the pair will not go forward to contest the team medals at the Tokyo Games after the gelding sustained a nosebleed.

Cian said that the nine-year-old Cardento gelding has “recovered well”, but that he will not be competing as part of the team competition as “the horse’s future is more important”.

The pair left all the fences standing in both Tuesday’s qualifier and the first round of Wednesday’s individual final. A solitary time fault kept the pair out of the jump-off and they finished equal with Britain’s Scott Brash in seventh.

“I’ve decided not to put Kilkenny forward for the team competition as his well-being comes first and I’ve no doubt we will have much success together in the future,” Cian said. “I’ll be here on the ground to help my team mates win a medal.”

He added: “[It’s been a] tough night, just finished [the] individual final, and myself and Kilkenny finished seventh. Unfortunately he had a nosebleed towards the end of the competition, but luckily he has recovered well, he looks great.

“The vets have checked him over and he seems fine. We’re allowed to continue to compete, but to me his future is more important. I’m going to be on the ground, I’m going to help Bertram [Allen], Darragh [Kenny] and Shane [Sweetnam] and please god they can get a team medal.

“We’ll be back to fight another day. I’m just happy he’s in such good shape and he jumped so well in both qualifier and final. To finish seventh at the Olympic Games isn’t so bad!”

An official statement from FEI Olympic director Catrin Norinder confirmed Kilkenny had a nosebleed (epistaxis) during the Olympic individual showjumping final.

“The nine-year-old Irish-bred gelding, which completed the course with just a single time fault, was checked by veterinarians immediately after the competition and, as a precaution, the horse will go to the onsite veterinary clinic for a further examination,” said the statement.

The statement added that under FEI jumping rules, blood on the flanks or in the horse’s mouth results in elimination, and that equine epistaxis (nosebleed) is not a cause for elimination.

Irish team vet Marcus Swail added: “Kilkenny jumped outstanding again today for Cian. Unfortunately he sustained a nosebleed towards the end of his round. He recovered quickly and all vitals were normal. He was subject to further examination at the on-site veterinary clinic and the horse is now comfortable and back in his stable.”

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• This article has been edited and approved by Karen Coumbe MRCVS, H&H’s veterinary advisor since 1991.

Is a nosebleed a minor issue requiring basic first aid or an emergency requiring prompt veterinary treatment? H&H explains…

Although nosebleeds in horses can look alarming, they are reasonably common and in most cases are not serious. Even a small bleed – or epistaxis as vets describe it – can look dramatic, particularly when suffered by a grey horse.

A true nosebleed tends to happen at rest, while blood seen in the nostrils after hard work is more likely to be originating from the lungs.

There are some causes of nosebleeds that are a serious cause of concern as they risk leading to extensive loss of blood and even death if left untreated.

Nosebleeds in horse: Is it serious? | Causes | Treatment | Diagnosis | Prognosis

Is it serious?

Most minor nosebleeds are not serious, with only a small amount of blood lost and the bleeding typically stops within 15min. If a bleed continues for longer than this, then you should contact your vet even if the amount is just a trickle.

Consider how much blood the horse has lost. Would the drips slowly fill a mug or rapidly overflow a bucket? If a Thoroughbred-sized horse loses more than about four litres (say half a big bucket) of blood rapidly, then you should call your vet as an emergency.

Is the blood coming from one nostril or two? A true nosebleed originating from within the head will normally emerge from one nostril. A horse bleeding internally from the lungs then blood is normally seen from both nostrils.

Is there any obvious reason for the bleeding? Has the horse knocked its head, had a fall or the vet has just passed a stomach tube up the nose? In these cases the bleed should be monitored and appropriate action taken based on the amount of blood being lost and the period of time the bleeding continues.

Has the horse just been exercising hard? If so then it is more likely to have an exercise-induced pulmonary haemorrhage, when the blood originates from the lungs.

Is it a one-off nosebleed? This may be a minor bleed that hopefully will not recur. If it has happened repeatedly this could a sign of a more serious problem and should be promptly investigated by your vet.

Common causes of nosebleeds in horses

Horses do not tend to have spontaneous nosebleeds, so there has to be a reason why the bleed has occurred.

A nosebleed occurs when any part of the nasal passages (which are richly supplied with blood vessels), throat, lower airways or lungs are injured to such a degree that blood vessels are damaged and blood leaks out.

The commonest cause is a simple knock on the head, when as a result of the head trauma an alarmingly large amounts of blood may pour from one nostril. Such traumatic nosebleeds are usually self-limiting, but always consult your vet.

Nosebleeds can also occur if the delicate nasal tissues are knocked inadvertently, for example, when a vet passes a stomach tube up from the nostril. Sometimes this is inevitable, particularly if the horse moves at the wrong moment, but the bleeding always stops.

A moderate nosebleed, if accompanied by coughing, could suggest a foreign body wedged in the nose or throat.

More serious problems include a progressive ethmoid haematoma, which is a lump that can grow inside the horse’s nose. It is similar to a giant blood blister and is aptly described as a “bleeding polyp”. It is a rare condition seen in around one horse in 2,500.

Guttural pouch mycosis is the typical and most serious cause of repeated nosebleeds, unrelated to exercise or trauma, and is a very serious condition that requires surgery to control the bleeding. Horses suffering from this condition can die of blood loss, so it should never be under estimated.

Occasionally tumours somewhere in the respiratory tract or inflammation of the sinuses (sinusitis) will produce a trickle of blood from the nose.

Bleeding from both nostrils after exercise is most commonly due to an exercise-induced pulmonary haemorrhage. This happens when bleeding occurs from the blood vessels within the lung and is associated with strenuous exercise, for instance, racing or eventing at a high level. Because the blood is coming up from the lungs, technically it is not a true nosebleed at all.

Treatment of a minor equine nosebleed

With any nosebleed, the horse should be kept as calm as possible. Do not try to pack the nose to control the bleeding as this will prevent your horse from breathing. Horses cannot breath through their mouths.

It may help to hold an ice pack or cold wet towel just below the horse’s eyes. If the bleeding is coming from inside the nose area, this may reduce it.

The average thoroughbred-sized horse will carry around 50litres blood inside them, so what looks like a lot coming out of the nose may not be critical for the horse. However, nosebleeds should not continue for more than 15min; if one does, your vet should be consulted.

Diagnosing the cause of nosebleeds in horses

When investigating the cause of a recurrent or persistent nosebleed, vets may use a range of techniques including most commonly endoscopy, where flexible tubing with a camera at the tip, allows the vet to see inside the nasal passages and airways to try and pinpoint the cause of the bleeding. If the bleeding is coming from within one of the bony sinuses (hollow cavities within the skull), it may be necessary to drill into the sinus to insert the endiscope and examine the interior. Other forms of imaging including X-rays, MRI and CT scans may also be use by the veterinary team to identify the problem after which appropriate treatment can be given.

Prognosis of nosebleeds in horses

In cases where a horse has suffered a one-off minor nosebleed, the vast majority will make a quick recovery and suffer no on-going issues as a result. The prognosis is more guarded in horses that suffer repeat nosebleeds and a vet should always investigate these. The outlook will depend on the specific cause, with some conditions requiring surgery.

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Ros Tate had never heard of the condition guttural pouch mycosis (GPM) until her dressage mare, Supreme’s Shania, was rushed to hospital last May.

After learning that emergency surgery was necessary, Ros endured a traumatic 24 hours before her mare sadly lost her life.

“My daughter had called me to say that Shania was having a nosebleed,” says Ros, who had bought the young Don Schufro daughter from Denmark two years previously. “I had never seen anything like it: blood was pouring from her nose and mouth. Luckily, one of our vets lives in our village. She recognised instantly that it was guttural pouch mycosis and told me to get Shania straight to hospital.”

The vets at Fyrnwy Equine Clinic waited for Shania’s condition to stabilise after the trauma of the bleed before they operated, but she collapsed on the way to theatre.

“This stopped her breathing, so she underwent an emergency tracheotomy,” explains Ros. “They couldn’t operate until the swelling had subsided, but the next morning she suffered another massive bleed and had to be put down.

“The shock of losing my beautiful mare in such horrific circumstances is something I’ll never forget.”

Artery erosion

The story serves to highlight the potential of GPM to kill. What can cause such a dramatic sequence of events? Phil Cramp MRCVS explains that the problem starts in two hard-to-access pockets located within the horse’s head.

“The guttural pouches are extensions of the Eustachian tube, an air-filled canal that connects the throat to the middle ear,” he says. “There are two pouches, one on each side, located just below the ear in the throatlatch region. Their purpose remains unknown.

Possible uses include pressure equalisation across the ear drum or warming of inhaled air, or they could serve as a resonating chamber for vocalisation or an aid in the cooling of blood that flows to the brain during exercise.

“Each pouch is divided into two compartments by the stylohyoid bone,” adds Phil. “There are a number of important structures within each pouch, including nerves that control swallowing, breathing and facial expression. Several major blood vessels also pass along the pouch walls, most importantly the internal and external carotid arteries and the maxillary artery.”

Phil explains that GPM is a fungal infection of one or both pouches.

“While the exact cause of the condition remains a mystery, the fungus Aspergillus spp. is often detected — alone, or in combination with other fungi,” he says. “Fungal plaques form within the pouches, most commonly along the walls of the major blood vessels and typically affecting the internal carotid artery.

“This fungal infection grows into and erodes through the vessel walls, resulting in the formation of an aneurysm [an excessive swelling]. This eventually leads to a hole in the vessel wall — and potentially a life-threatening haemorrhage.”

Red alert

According to Phil, there is nothing an owner can do to prevent GPM.

“It is vital to recognise the clinical signs and act promptly,” he says. “A nosebleed is the most common sign — this is typically moderate to severe and the blood is bright red in colour as it is coming direct from an artery.

“There are usually a number of smaller episodes before a potentially fatal bleed. While it’s sensible to contact your vet about any nosebleed, a significant loss of blood should be treated as an emergency.

“The second most common sign is difficulty eating and swallowing, a condition called dysphagia,” adds Phil. “This occurs if the fungus damages the nerves that control tongue movement and swallowing. Dysphagic horses often struggle to eat and may be seen quidding [dropping unchewed feed], packing feed in their cheeks and coughing because they cannot swallow normally.

“Other signs less commonly observed include the development of Horner’s syndrome, which causes a drooping eyelid, constricted pupil, sunken eye and patchy sweating on one side of the neck only. There may be white nasal discharge, an abnormal head posture and pain in the throatlatch region, or an abnormal respiratory noise due to damage to the nerves that supply the muscles of the throat.

“These more generalised signs can be caused by many other disease processes, but if any were present, your vet would always look to rule out a guttural

pouch disease.”

Phil explains that a definitive diagnosis can be made by performing endoscopy of the guttural pouch, which involves passing a small, flexible tube with a camera tip or fibre optics up the horse’s nose.

“Once the endoscope has been passed into the nasopharynx, which is a cavity located above the soft palate, blood can typically be seen coming from one or both of the guttural pouch openings,” he says. “As the endoscope enters one of the pouches, it is usually possible to visualise the fungal plaque — seen as white, tan and black membranes overlying one or more blood vessels. This is 100% diagnostic.

“At this point, you should be either taking your horse into your vet’s clinic, an equine hospital or arranging referral to a specialist centre for treatment. Once there, the horse will undergo further evaluation in an attempt to determine exactly where the fungal plaque is growing and which vessel is affected.”

Worst-case scenario

While surgery is effective in the majority of cases, Shania never reached the operating table.

“It’s pot luck how big the hole is in the carotid artery,” explains Jim Tipp MRCVS of Fyrnwy Equine Clinic. “The first bleed is usually a major warning and the second is likely to be fatal, so the situation is a ticking time bomb until surgery can take place. You really don’t know when the next bleed might occur — it could be an hour later, or a month.

“Unfortunately, Shania’s circumstances formed the worst-case scenario,” he says. “She had what’s called a dissecting haemorrhage, where she bled into the tissues around her brain. The severity of the fungal infection and the extent of the resulting bleed made surgery impossible.”

Reflecting on her mare’s history, Ros adds: “She did drop food from her mouth, from first arriving in the UK, and a day doesn’t go by when I don’t wish I had persisted in investigating this.

“The condition is treatable, if caught in time,” she adds. “If this story helps another owner recognise the signs, at least some good may come out of Shania’s death.”

Surgical options

Vet surgeon Phil Cramp explains that guttural pouch mycosis requires surgical treatment.

“There are reports of successful medical management consisting of treatment with topical and systemic anti-fungal drugs, but the risk of a fatal haemorrhage is too high,” he explains. “Surgery is aimed at occluding [closing up] the affected artery. Without blood supply, the fungal growth stops and can then resolve without further treatment. Most surgeons elect to treat the fungus topically for a week or so after surgery, however, to ensure a successful resolution.

“There are two main surgical procedures, both of which require a general anaesthetic. One involves placing an inflatable balloon, attached to a flexible catheter, into the affected artery via an incision in the upper neck. Once positioned, the balloon is inflated to stop the flow of blood.

“In another procedure, small coils or plugs are placed in the affected artery using a real-time imaging method called fluoroscopy. While very accurate, this technique requires specialist equipment and is not widely available.

“Success rates for both procedures are good, although it can take a long time for some of the clinical signs associated with nerve damage to disappear. The fungal plaques may take up to six months to resolve fully.”

Ref: Horse & Hound; 1 March 2018

Hidden at the base of the horse’s skull is a pair of air-filled guttural pouches. These are pockets, or “out-pouchings”, of the auditory (Eustachian) tubes, which connect the nasopharynx (the area between the nasal cavity and the larynx) to the middle ear.

Humans do not have these structures — they are present only in the horse, the rhino, the tapir, a small rabbit-like creature called the hyrax, certain bats and a species of South American mouse.

The role of the guttural pouches is not known for sure. The most recent and promising theory is that the air in the pouches cools the blood supply to the brain. Preventing overheating of this sensitive organ is particularly important during fast exercise, when the temperature of circulating blood can increase by up to 2°C.

In an average 500kg horse, each of the guttural pouches measures about 450cm3 in volume (roughly the size of a fist). They are bordered by many vital anatomical structures, including the base of the first vertebra, the pharynx, various muscles and the parotid and mandibular salivary glands. This makes both medical imaging and surgical access challenging.

The left and right pouches are completely separate, and are divided by a thin membrane called the midline septum at the top, and the rectus capitus and longus capitus muscles at the bottom. Each pouch is then partially divided by the stylohyoid bone into an outer (lateral) and inner (medial) compartment.

There are numerous crucial structures running within the walls of the guttural pouches. These include large arteries and veins, plus cranial nerves that are vital for a variety of neurological functions including swallowing, pharyngeal tone and sympathetic nerve supply to the head. There are also large lymph nodes in the floor of the pouches, which can harbour infection — for instance, in cases of strangles.

Diseases affecting the guttural pouch can damage some or all of these structures. This is what makes guttural pouch disorders so serious and often life-threatening. Because of their location deep within the horse’s head, by far the easiest way to view what is going on inside the pouches is by using a flexible endoscope. A camera is passed up the nose and guided through the narrow Eustachian tubes, the entrances of which are marked by a flap of cartilage.

It can sometimes be difficult to pass the scope into the pouches, particularly if the horse is small or if the pouches are narrowed by inflammation. X-ray examination of the pouches can at times be useful.

Fungal infection

The most feared disease of these structures is guttural pouch mycosis, which carries an overall death rate of 50% in untreated horses.

A fungal plaque develops on the back wall of the guttural pouches. This fungus has a predilection to grow right on top of the internal or external carotid arteries, or both. Erosion of the wall of these major arteries causes bleeding, and blood is seen at one or both nostrils.

Often, a small, seemingly innocuous nosebleed will precede a major, life-threatening haemorrhage. It is for this reason that all nosebleeds (other than those in horses known to have sustained facial trauma, or racehorses after fast exercise), should be investigated with relative urgency.

The fungus can also erode the cranial nerves. This results in various neurological abnormalities, including laryngeal paralysis (roaring), and Horner’s syndrome, which causes changes to the eyelid position and the pupil of the eye, along with abnormal facial sweating. A further abnormality is difficulty swallowing, which may be so severe that the horse develops aspiration pneumonia.

The fungal plaque itself is malodorous. Many affected horses also have a history of an unpleasant-smelling purulent (pus-like) discharge from both nostrils. Treatment involves surgery to block the affected artery, thereby preventing a fatal bleed. This can be achieved by simple ligation (tying) of the vessel, or the insertion of a catheter into it to block off a longer segment of the artery.

More recently, insertion of metal coils into the artery to block off the bleeding section has been described. This has the advantage of being performed in a minimally invasive way via a small incision in the neck.

Topical administration of anti-fungal solution to the plaque within the guttural pouches on a regular basis is also recommended, once ligation of the artery has taken place.

Pus in the pouches

Guttural pouch empyema is a condition associated with infection with Streptococcus equi var. equi, a bacterium known as strangles. Abscesses may form in lymph nodes in the floor of the pouches, which then burst and leak pus into the pouch interior. Pus may be seen draining from the Eustachian tubes into the nasopharynx, and the horse may have enlarged lymph nodes.

Pus, either in liquid form or as solid concretions called chondroids, may also occur on the floor of the pouches. Laboratory testing of fluid pooling within the pouches should confirm the diagnosis of strangles. Chronic carriers may harbour the bacterium within the guttural pouches, with or without obvious pooling of fluid or chondroid formation.

Horses afflicted with viral upper respiratory tract infections, or bacterial infections other than strangles, can also occasionally develop inflammation and pus within the guttural pouches. Daily lavage (flushing) of the pouches may be useful to encourage drainage of purulent material, while chondroids must be physically removed before infection can be resolved. Lavage is often followed by direct installation of penicillin solution.

Various surgical approaches can be used to remove chondroids from the pouches if they are too large or too numerous to be retrieved with trans-endoscopic instruments. Other disorders are relatively rare but include guttural pouch tympany, which is an accumulation of air within the pouches, and neoplasia — the development of tumours.

Ref Horse & Hound; 27 October 2016

What is the significance of blood in a horse’s nostrils after hard work? Dr Colin Roberts discusses exercise-induced bleeding and its effect on athletic performance

It has been recognised for centuries that bleeding from the nostrils — known as epistaxis — is seen in some horses after strenuous exercise.

Famous thoroughbred racehorses from the past that were reported to have experienced this during races include the highly influential stallions Bartlett’s Childers and Herod. More recently, the occurrence of the condition in elite steeplechasers Best Mate and Sprinter Sacre has hit the headlines.

For many years it was assumed that the site of the bleeding in horses with epistaxis associated with racing was the upper airways. However, in a seminal scientific paper published in 1974, Professor Bob Cook put forward the notion that the source of the

blood was in fact the lungs.

The condition is now known as exercise-induced pulmonary haemorrhage (EIPH) and we know that it occurs primarily in the upper, rearmost part of the lungs

Only a small proportion of racehorses bleed visibly from the nostrils. Upon examination of the respiratory tract with an endoscope shortly after racing, however, a very large proportion are found to have blood in the trachea (the windpipe). This demonstrates that they have bled into their lungs during the race.

When endoscopic surveys of the prevalence of EIPH have been conducted around the world, 40-75% of horses have been found to have bled during racing. A survey carried out by the author in Flat racehorses in the UK found an overall prevalence of 55% with an increase in frequency between the ages of two and four years.

These surveys demonstrate that EIPH occurs commonly in racehorses, but in fact, analysis of respiratory secretions obtained endoscopically from horses in training (by the technique of tracheal wash sampling) yields evidence that virtually all racehorses experience EIPH to some degree once they commence fast work.

Epistaxis during racing is usually associated with the highest grade of EIPH and it is likely to be accompanied by impaired performance. In horses that show epistaxis only upon lowering the head after racing, the EIPH grade can be lower. In these cases, it may not affect performance.

Reports of the relationship between EIPH that is detectable only by endoscopic examination and race finish position are conflicting, with positive and negative associations, as well as no relationship being reported in various studies around the world.

In some countries — for example, Hong Kong and Australia — horses with recurrent nosebleeds due to EIPH are banned from racing.

Why do horses bleed?

While the cause of EIPH remains uncertain, the most widely accepted explanation is that it usually occurs due to stress failure of the pulmonary capillaries.

This causes bleeding into the alveoli (air sacs), as a result of the unusually high blood pressures seen in the pulmonary circulation of the exercising horse. Additionally, the negative pressure that occurs in the alveoli during inspiration probably adds to the pressure across the capillary walls, making them even more likely to burst.

The roles of upper and lower airway disease as causes of EIPH are still under debate, but it seems likely these factors may exacerbate the “normal” level of bleeding in some animals.

The blood-gas barrier (the division between the gas in the alveoli and the blood in the pulmonary capillaries) must be strong enough to resist the stresses placed upon it during strenuous exercise. Yet it must also be extremely thin to facilitate gas exchange, as gases pass much more efficiently between the alveoli and the capillaries if the distance that they must travel is small.

It is probably the need for the blood-gas barrier to strike a compromise between thinness and strength that makes it so susceptible to the occurrence of EIPH.

It is also noteworthy that since the equine lung does not respond to training, the increased maximal cardiac output which the horse is capable of as a result of conditioning is directed through a pulmonary vascular system that will not improve during the training process. This being the case, it may be that it is the fitter, highly performing horse that is more likely to experience EIPH.

To treat — or not?

Many different medications have been used to treat EIPH, the vast majority of them without scientifically demonstrable effects.

The drug most frequently used is furosemide, a potent diuretic (a drug that increases the production of urine) that is permitted for the treatment of EIPH in racehorses in some countries, primarily in North America. It is more commonly known by its trade name Lasix.

Furosemide does not prevent EIPH, but it does reduce its severity — probably by lowering pulmonary arterial and hence pulmonary capillary pressure. Furosemide is not permitted in racing in Europe, but it is used during training gallops for horses perceived to perform poorly due to EIPH, although it is unclear whether this has tangible benefits when the horse then goes on to race without it.

When considering whether a horse requires treatment for EIPH, it should be remembered that unless the condition is severe, it is probably not significant.

Besides furosemide, numerous other medications have been used in an attempt to prevent EIPH. No pharmacological agent is licensed for this use in horses, so treatments are generally empirical, with little firm evidence of their efficacy.

There is some debate about the use of commercially available adhesive nasal strips, which can reduce upper airway resistance and may reduce EIPH to some degree. They are permitted in eventing in the UK, but not for racing.

Different disorders

There are many other reasons for nosebleeds. Although horses showing epistaxis during, or shortly after, exercise usually have EIPH, when nosebleeds occur at rest they are more likely to be due to one of a range of upper airway disorders — some of which may be life-threatening and need immediate veterinary attention.

Although it is relatively uncommon, sudden death does occur after intense exercise in a small number of horses. In many cases, bleeding in the lungs is found on postmortem examination. These fatal haemorrhages may well represent a different condition to proper EIPH, involving as they do, the rupture of larger blood vessels rather than capillary bleeding.

H&H 18 June, 2015

Catherine Lawton sensed that something was amiss last autumn when her otherwise healthy 14-year-old gelding Eric suffered a few minor nosebleeds. Endoscopy revealed an ethmoid haematoma, a solid build-up of blood and mucus in a sinus compartment.

“The mass was quite difficult to get to, but my vet suggested a series of formalin injections to try to break it down,” says Catherine. “Eric coped well with the injections, although sometimes blood and mucus would come out of a nostril, which needed cleaning up.”

In spring, Eric underwent a computed tomography (CT) scan to check the size of the mass.

“The haematoma was not responding well to treatment,” explains Catherine.

“It was decided that the best option was to treat it through a trephine site [a hole made in the skull] with multiple formalin injections. Eric came home with a big plaster on his head, but when it came to re-dressing the site I nearly fainted. The hole was the size of a £2 coin and you could see inside the skull and the haematoma itself!

“A further attempt to eradicate the mass by laser removed only 40% of it and unfortunately the dexamethasone he was given for the swelling at the trephine site triggered steroid laminitis.

Treatment has been on the back-burner, but the lameness is now under control.

“We hope that the haematoma is growing slowly, otherwise we may consider more injections through the trephine site.”

Identifying the mass

Ethmoid haematomas are thankfully relatively rare. While it can affect horses of any age, most cases have been seen in middle-aged (around 10 years old) thoroughbreds.

The most common clinical sign is that of mild, intermittent blood trickling out of one nostril only. This can be accompanied by an abnormal respiratory noise, especially if the haematoma is large and is occupying a substantial part of the nose.

In really severe cases, the haematoma can start to deform the horse’s skull. This causes swelling of the head, which can be painful and may result in head shaking, head shyness or any behaviour associated with a horse having a headache.

Occasionally, in cases of fast-growing or long-standing disease, the haematoma may actually grow so large that it appears at the nostril.

The quickest and easiest way to diagnose the problem is for the vet to perform an endoscopy examination, which is when a flexible camera is passed up the horse’s nose to visualise the nasal cavities and upper airway. Not all ethmoid haematomas can be seen, however, so additional diagnostic imaging such as X-rays may highlight an opacity consistent with the condition.

The most accurate diagnostic method is a CT scan of the horse’s head. It is highly likely that any soft tissue mass in the region of the ethmoid turbinates is a haematoma, but other possibilities include abscesses, sinus cysts or – very rarely – tumours.

Shrink or burn?

The progressive nature of an ethmoid haematoma means that it will keep on growing, making treatment a necessity. The three main options are all aimed at removing the mass and destroying its origin.

A relatively cheap and risk-free option is intra-lesional injection of the mass with formalin. This substance destroys the mass so that it gradually shrinks in size. The formalin is injected via a needle attached to a catheter, which is fed down the working channel of an endoscope.

While this method is minimally invasive and can be carried out on an outpatient basis, the treatment must be repeated – usually every 3-4 weeks until the mass has been resolved. Up to 18 treatments have been required in some cases, but most cases resolve with between three and five injections.

An alternative treatment is laser ablation, which is also performed via an endoscope and is recommended for small haematomas measuring less than 5cm in diameter.

The laser is used to “burn” the haematoma until the all of the tissue has been destroyed. Treatment usually has to be repeated and is checked at seven-day intervals.

Surgical options

Surgical removal (resection) of the mass is carried out under standing sedation. There are a number of different ways in which the mass can be approached, depending on its size and exact location.

Essentially, a hole must be created in the horse’s skull to access the sinuses and the mass. This can be a small hole, a larger trephine hole or a large, hinged bone flap.

The large trephine or flap is my preference, so that the entire mass can be dissected out and removed completely. Smaller trephines, as in Eric’s case, however, are ideal if access to the base of the haematoma is all that is required.

Surgical resection can cure the problem in one fell swoop, but there are some risks to consider. Bleeding is a genuine danger and can occasionally be severe. It is always sensible to have access to edonor blood in case a transfusion is required, even if this is very unlikely.

Dehiscence, or splitting, of the surgical incision and the trephine hole is also a potential risk, as is failure of the trephine hole to fill in. Unfortunately, there is nothing that can be done to predict that this might occur, or indeed do anything to reduce the chance of it happening.

It would appear that sometimes the bone is reactive and swells following surgery and then just fails to heal up. Thankfully, this is very rare.

The prognosis is poor if an ethmoid haematoma is left to grow unchecked, but the chances of recovery are good with appropriate care.

Eric’s case highlights the fact that a combination of treatments may be necessary to successfully eradicate the encapsulated mass in its entirety.

Multiple treatments are often necessary and recurrence is relatively common (in up to 43% of cases). Regular endoscopic checks are a good idea so that any re-growth can be detected and dealt with promptly.

This article was first published in Horse & Hound magazine (2 October 2014)

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