BLEEDERS

Exercise Induced Pulmonary Haemorrhage (EIPH) is the medical term for a condition that occurs in racehorses, which is commonly called Bleeding, or “Burst a Blood Vessel” as is sometimes announced after a race.

This condition has been reported for over a century and one of the most celebrated racehorses of his era, an Epsom Derby winner, Ormonde was also a “bleeder”.

The treatment or management of this condition is one of the bigger challenges facing the Veterinary Profession. The increasing number of cases that are being diagnosed on endoscopy and the subsequent control on their participating in the races has the potential to impact the fields and it can escalate into an issue for the Turf Clubs to address.

The surest sign that a horse has suffered from EIPH during a race is that the horse suddenly stops accelerating when it is under pressure. On their return to the unsaddling enclosure they often cough. This is then followed by an expression of blood at the nostrils be it a trickle or a copious amount. On some occasions this trickle is noticed when the horse has gone back to the stable and starts to drink water or pick at hay.

The degree of bleeding is generally graded from Grade 1 to Grade 4, Grade 1 being specks of blood noticed on endoscopy to Grade 4 being copious amounts of blood being expressed at the nostrils.

A large percentage of horses suffer from this condition to varying degrees, what is apparent is that those who do not “bleed” run better races or up to their potential. Until the advent of endoscopy we had absolutely no idea about the enormity of this problem. It was only if blood was expressed at the nostrils would that horse be called a “bleeder” and the horse was then treated for the condition.

To understand EIPH one must start with knowing how a horse breathes at exercise. At a gallop the horse breathes at a mind-boggling frequency of two and a half breaths per second. The horse runs with his mouth closed ensuring that air is inhaled only through the nostrils. The respiration is completely in sync with the horses stride. When the horses’ forelegs hit the ground, the horse is exhaling, the abdominal contents are forced forward due to the movement and compress the diaphragm, to force all the air out of the lungs. When the hind legs are hitting the ground, the horse is inhaling, the gut contents are pushed back and they in turn act like the plunger of a syringe and suck 15 litres of air into the lungs at each breath.

It is the dynamics of this respiration and the pressure gradients to which the blood vessels in the lungs are subjected are so forceful, that any hindrance to the airflow into the lungs can cause the fragile lung tissue to tear. Once lung tissue is torn it isn’t replaced with the elastic lung tissue but by scar tissue, which is not as elastic and therefore easily torn, resulting in a hemorrhage. The more the scar tissue from repeated insults, the greater the frequency of the horse suffering from EIPH.

There are many factors that cause EIPH and they could be broadly divided into infectious to non infectious.

Infectious causes would be bacterial or viral lower airway disease, evidenced by the presence of mucous/ mucopus. Any infection, which scars the lung tissue, will cause a horse to be susceptible to EIPH.

Non-infectious causes would be mechanical obstruction of the airway such as Dorsal Displacement of the Soft Palate (DDSP) or choking, Dynamic Pharyngeal Collapse (DPC), Idiopathic Laryngeal Hemiplegia (ILH) or “Roarers” or any other condition that will affect airflow dynamics.

As with any condition the treatment has to address the cause and the recurrence or otherwise of this condition will depend entirely on the degree of damage to the lung tissue and the success in removing the exciting factors.

MUCOPUS

An infection of the Respiratory Tract is invariably caused by bacteria or a virus. The external signs would be a cough and or a nasal discharge. However the cough need not necessarily be indicative of a respiratory infection and the nasal discharge may also emanate from the sinuses or from the guttural pouch.

Today with the use of endoscopy it is possible to be able to quickly diagnose a whether the horse has a respiratory infection or not by the presence or absence of mucopus.

“Mucopus” is a term coined as a mixture of mucous and pus and this is observed in the trachea (wind pipe) of horses suffering from a respiratory infection. Mucopus is not necessarily observed only when there is an infection, as poor stable environment and pollution can also cause the presence of mucopus.

Every practitioner grades the quantity on their own scale but its usually graded from Grade 1 to Grade 4 (Grade 4 being the maximum). What every practitioner does when they observe the presence of mucopus in the trachea is to treat the horse with a course of antibiotics and mucolytics or antibiotics alone whether it is by injection or oral or inhalation. In cases of a persistent infection the mucopus is collected and subjected to a culture and sensitivity test to check which antibiotic is best suited to cure the infection.

When a horse is suffering from a respiratory infection it obviously cannot deliver its best effort. There are greater chances of the horse suffering from EIPH as a result of the added pressure on the respiratory system.

Dr. Hasneyn Mirza, is one of the most respected and sought after Veterinarians in the country specializing in equines.