How the BAL Test is Helping Us Identify and Treat Inflammatory Airway Disease in Performance Horses
A horse moves incredibly large volumes of air in and out of its lungs. The equine respiratory tract is a highly specialized organ system, incredibly effective in exchanging oxygen for carbon dioxide at a rate far higher than even the most elite human athlete. The human respiratory tract is specialized for speech, but the horse is made for exercise.
It’s no wonder horses are some of the most impressive athletic creatures. Whether it’s on the race track, around barrels, over jumps, in the cattle pen, or over a high mountain pass, the performance of a horse is awe-inspiring - until somethings not working quite right. Because of the high demand, and high volume of oxygen exchange in a horse's lungs, even a small problem within the system can cause a big impact on performance.
Inflammatory Airway Disease (IAD), sometimes also known as small airway inflammatory disease (SAID), is a condition affecting 22-50 percent of athletic horses. A cascading immune response causes inflammation in the lungs. Mucous and cellular debris accumulate, the airways constrict, and the intake and outflow of air is restricted. IAD is very similar to asthma in humans.
The more intense the exercise, the bigger the effect of IAD on performance. For barrel racers, race horses, and competitive endurance horses even mild IAD can deteriorate performance quickly. Jumpers and dressage horses may perform fine for years, not noticing a decline until the condition becomes more severe.
Both the condition, and it’s cause, can be difficult to diagnose. The symptoms of IAD can overlap with other diseases, be subtle, or come and go. But experienced riders often say, “somethings just not right.”
The number one symptom of IAD is reduced performance. Trainers and riders complain their horse seems sluggish or lethargic. This exercise resistance gets progressively worse over a matter of days to weeks.
Other symptoms may include:
Coughing – often intermittent, sometimes only at the beginning of exercise
Airway mucous – identified by scoping, not externally visible
Bleeding in the lungs – discharge of blood may even become visible in the nostrils after exercise.
It’s important to note, horses with IAD do not have signs of infections or contagious respiratory disease, such as fever. In IAD, blood work is often normal and the horse is otherwise healthy looking.
Uncovering the Cause – BAL Testing
While researchers continue to look for genetic or other factors to IAD, what we do know is that dust, allergens, molds and fungi, bacteria, air pollutants, and viral respiratory illnesses can all contribute to the condition. Unless we determine each animal’s underlying cause, treatments may just be a shot in the dark.
One of the most definitive options for diagnosis is through bronchoalveolar lavage - a BAL test. Through this procedure, fluid collected directly from the lungs is tested in a specialized lab. At Black Diamond Equine we work with equine specialty labs, including Purdue University, one of the leading research and development labs in equine respiratory care.
Testing of the lung fluid not only confirms the presence of inflammatory cells and/or blood, but can tell us the type of cells found and therefore the underlying cause. For example, the lab may find a low-grade bacterial infection present. Or they may find eosinophils, a sign that allergic reaction is taking place and creating the inflammation. When we know the cause, we can more effectively determine the best course of treatment.
Not only does BAL give us information on the specific cause of the condition, it also gives us a bigger window to diagnose the problem. In the past, horses found to be bleeding or suspect of IAD had to be scoped at the track or arena immediately after a race. The veterinarian had to “see” the active process in the lungs. However, with BAL testing, the procedure is done in clinic and is accurate even 3-4 weeks after suspected bleeding events.
Treatment of IAD
The best treatment is one that directly addresses the underlying cause of respiratory distress. While we tailor treatment to each case, four main goals remain the same:
1. Open the airways – We may use bronchodilators to open airways, stop the spasms in the lungs, and bring immediate relief.
2. Reduce Inflammation – A course of specifically chosen anti-inflammatory may be used either orally, by injection, or given as an inhaled steroid.
3. Remove the triggers – Managing the environment is key for long-term control of IAD. This can include reducing exposure to potential allergens such as mold. Minimizing dust in the barn. And maintaining a good vaccination schedule to prevent viral respiratory disease, which may trigger or worsen IAD.
4. Rebuild fitness – Just as a couple weeks on the couch makes it harder for you to exercise, so our equine friends need to re-build their muscle, endurance, and fitness level after time off. Allowing the lungs to heal and the body to rebuild takes patience, but pays off in the end.
With the right evaluation, the right tests – like a BAL test – and the right treatment we can help get you and your horse back in the game.