Respiratory diseases are frequently encountered in horses. Several diseases can cause nasal effusion or cough, e.g. inflammation of the throat, the guttural pouch, the lungs or the pleural cavity. Specialised examinations such as endoscopy, broncho-alveolar lavage (BAL), measurement of arterial oxygen tension, ultrasound and radiography can be used to determine the exact cause.

During endoscopy, a flexible camera (endoscope) is entered through the nose in order to visualise the nasal cavity, ethmoid turbinates, guttural pouches, trachea (Fig. 1) and main bronchi. A BAL can be performed to examine the inflammatory response in the lower airways and to isolate bacteria. Based on these examinations, a targeted treatment plan can be initiated.

With a dynamic endoscope (Fig. 2 + click to see video), the horse's airway can be visualised during exercise. Dynamic airway problems are difficult to detect at rest. The overground endoscopy is indicated in horses presenting a cough, abnormal noises during exercise and even in horses with unexpected underperformance.

Ultrasound allows examination of the lungs and the pleural cavity. This technique can be used to detect abnormalities such as fluid effusion in the pleural cavity (Fig. 3 + click to see video), collapse of the lung alveoli, adhesions between the outer and the inner pleura, lung tumours or lung abscesses. In addition, ultrasound guidance can be used to perform lung biopsies.

When an accurate diagnosis has been made, targeted therapy is initiated. Medication can be administered orally, intramuscularly, intravenously or by aerosol (Fig. 4).

Contact: Da. Laurence Lefère and Dr. Dominique De Clercq