the entire upper airway is examined. Examination
should not stop at confirmation of the suspected lesion
because some horses have more than one problem.
The examiner should ascertain whether the lesion in
question is compatible with the history and the signs
that the horse is exhibiting.
Some conditions are not apparent at rest. Exercising
the horse under tack or harness under the conditions
in which the owner or trainer reports the problem is
helpful. Endoscopic examination is then performed
at the conclusion of exercise. Racehorses may be
examined on the track during training by waiting
near the finish line to hear any noise generated and
to perform an endoscopic exam at the termination of
work.
The following list is not all inclusive; rather, it covers
the most common upper respiratory causes of exercise
intolerance in performance horses in descending order
of frequency. Differences in clinical presentation and
response to therapy in horses engaging in different
activities can create some overlap in diagnostic
perception.
• Laryngeal Hemiplegia
• Dorsal Displacement of the Soft Palate
• Epiglottic Entrapment
• Epiglottic Hypoplasia
•
•
•
•
•
•
Arytenoid Chondritis
Ethmoid Hematomas
Pharyngeal Cysts
Hyperkalemic Periodic Paralysis
Maxillary Sinus Cysts
Guttural Pouch Empyema
Retropharyngeal Abscesses
• Alar Fold Obstruction
• Nasal Collapse
and
The respiratory system is a frequent cause of exercise
intolerance in performance horses. Labored breathing,
fatigue during performance and prolonged recovery
after exercise are common complaints. Inadequate
fitness level and diseases of the cardiovascular system
are differential diagnoses that share these complaints
and should be investigated. Generation of increased
airway noise is a clinical sign that implicates the
upper respiratory system. A careful history from the
owner, trainer, and endoscopy of the upper airway
are the most useful tools. Endoscopy during exercise
on a treadmill is indicated when the airway lesion is
not apparent with endoscopy at rest. Treatment of
the respiratory obstruction may differ with the level of
performance required.
Dr. Craig Sweatt • Dr. Tom Hutchins • Dr. Stacy McLeod
8283 FM 920 • Weatherford, Texas • 817-458-3355
Small Animal •Equine •Livestock •Ambulatory Services
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