What is up my horse’s nose?

Bleeding from the nose is a relatively common clinical complaint and can be quite distressing for owners. If your horse has a nose bleed, it is best to keep the horse quiet and calm so that the bleeding will stop. In most instances, the bleeding will stop in 15-20 minutes.

When presented with a nose bleed, there are several questions that your veterinarian will ask. The first question is whether the bleeding is from one or both nostrils. Other questions we will ask are: Has this happened before? What were the circumstances that brought about the nose bleed? Was the horse exercising or at rest? Was there a traumatic incident? How much blood was there? Was it just a trickle or a gusher? These questions help us start to put the pieces of the puzzle together. However, the key piece of diagnostic equipment that we use to determine the source of the hemorrhage is a video endoscope. An endoscopic exam allows us to visualize the inside of the respiratory tract on a monitor. The image is produced through the scope that is introduced into the nasal passage and is then advanced to visualize the entire upper respiratory tract. There are many different causes and there are several different locations within the horse’s respiratory tract that can serve as the origin of a nose bleed. Most conditions that create hemorrhage from the nose are not life threatening; however, there is one condition that can result in death. This condition, called guttural pouch mycosis (a fungal infection in the guttural pouch) is fortunately not common.

Some causes of nose bleeds include: ethmoid hematomas, EIPH (exercise induced pulmonary hemorrhage), sinus problems, trauma, foreign bodies, infections and tumors.

Ethmoid turbinates are normal structures within the nasal passages that warm the air as it passes over them. They are highly vascular and therefore can easily bleed. This is the most common cause of nosebleeds after a horse has had a stomach tube placed because the tube can traumatize the turbinates as it is being passed.

Ethmoid hematomas are a tumor that consists of a mass of abnormal blood vessels that can grow on the ethmoids. This is not a life threatening condition but will often result in mild hemorrhage, as well as head tossing and exercise intolerance. In some cases, these masses can get quite large, occluding air flow through that nasal passage. Diagnosis is done by using an endoscope to visualize the nasal passage and upper respiratory tract. Treatment is usually a series of injections of dilute formalin to shrink the mass. In some cases a laser may be used to ablate the tumor.

EIPH is a common condition in race horses and to a lesser degree in barrel horses. It is hemorrhage that originates in the lungs, secondary to an intense maximal exertion. It is estimated that anywhere from 40-75% of race horses have EIPH. However, less than 10% of these horses actually have visible bleeding from their nostrils. Diagnosis is based on history of exercise-induced bleeding, cough, exercise intolerance or a decrease in the horse’s performance level. Hemorrhage in the trachea can be visualized 30-60 minutes post exercise with an endoscope. In many cases the horse cannot be scoped that soon after exercise and we will instead see an abnormal puddle of discolored fluid within the trachea when the horse is scoped. In some cases we will take a sample of fluid for analysis to help us come to a diagnosis. We also have a longer scope that will allow us to go into the horses lungs and look at these structures for blood. Once the diagnosis is made these horses will usually be prescribed a drug called Lasix (furesomide). This drug will be used pre-race to decrease the severity of the bleeding. A large percentage of racehorses are given Lasix pre-race after the horse has been confirmed as a “bleeder” by scoping.

The most serious condition that results in hemorrhage from the nostrils is called guttural pouch mycosis. This is a fungal infection that develops within the one of the guttural pouches. Horses have two guttural pouches which are extensions of their auditory tubes and have an opening into the back of their throat. There are several very important structures present within the pouches: several cranial nerves and the internal carotid artery. If the infection causes significant damage to this artery it can rupture. Endoscopic examination of the guttural pouch can diagnose the problem before life threatening events can occur. Treatment is an intensive daily infusion of anti-fungal medication into the pouch. This is a long treatment course as the fungal infection is difficult to resolve.

Uncommon miscellaneous conditions that can cause nose bleeds include foreign bodies, infections or tumors in the nasal passages or sinuses. Trauma to the head or face is the most common cause of nose bleeds these and will usually resolve within a short time. The bottom line for diagnosis of nose bleeds is the use of an endoscope to image the areas in question. As they say a picture is worth a thousand words.