Page 702 - The Veterinary Care of the Horse

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Figure 15.20 Streaks of blood in the trachea of a horse with EIPH

Up to 75% of Thoroughbreds have some blood in their windpipe after racing. It also occurs

in other sport horses that perform at speed such as polo ponies and eventers.

Causes

The condition is not fully understood. It is thought that the high pressures that develop in the

lungs during racing are sufficient to rupture the small capillaries that surround the alveoli (air
sacs). Horses with underlying airway inflammation from infection or recurrent airway

obstruction (RAO) are more likely to bleed. Poor air hygiene from dust, fungal spores and
ammonia are all contributory factors. Laryngeal hemiplegia may also predispose to the

condition.

Diagnosis

The diagnosis is made on the history, clinical examination and endoscopy. Endoscopy is

essential to determine the source of the bleeding and rule out conditions such as guttural
pouch mycosis. If there is no blood at the nostrils and EIPH is suspected, the horse should be