Exercise Induced Pulmonary Hemorrhage

Exercise Induced Pulmonary Hemorrhage (EIPH) also known as "bleeding" or a "bleeding attack" has been known to occur in horses that engage in short periods of strenuous exercise. These horses usually include Thoroughbred and American Quarter Horse racehorses (incidence of 50-75%) and standardbred racehorses (incidence of 40-60%), but it may also occur in jumpers, polo ponies, and draft horses that pull competitively. It appears rarer in stallions than mares or geldings, but it is associated with airway inflammation and increasing age.

The affliction occurs when blood enters the air passages of a horse's lung, due to fractured lung capillaries. Blood is sometimes evident discharging from a horse's nostrils (epistaxis), however, this usually only occurs in 5% of bleeders. If a horse does not exhibit epistaxis but is suspected to have EPIH, an endoscopic exam is performed soon after the horse is exercised.

It is believed that nearly all horses experience it (when exposed to strenuous exercise) and it has the potential to decrease lung function over time.

Treatment
The drug commonly known as Lasix (Furosemide) has been used to prevent the condition, although it does not work in 50% of cases, and it is banned in some countries. Any racehorse in Australia that suffers from a bleeding attack during or following a race receives an automatic 3-month ban from racing. A further occurrence results in a lifetime ban.

Other treatments that have been used include bronchodilators, coagulants, and estrogen.