Respiratory Tract

The horse’s respiratory tract is responsible for moving air from the atmosphere to the lungs and vice versa. The respiratory tract is divided into upper and lower portions. The upper respiratory tract is composed of the structures from the nostrils to the cervical trachea (the part of trachea outside of the chest). The lower respiratory tract consists of the thoracic trachea (portion with the chest) and the lungs. Diseases of the upper and lower respiratory tract can be corrected either medically or surgically, depending on the diagnosis. Consequently, the key to treating any respiratory disease is obtaining an accurate diagnosis in the beginning. Texas A&M is fortunate to be equipped with state-of-the-art diagnostic equipment to assist us in doing just that.


Signs that my horse may have an upper or lower respiratory tract disease:

  • My horse makes noises while breathing, especially when exercising.
    • Whistle
    • Roaring
    • Gurgling
    • Rattle
  • My horse is exercise intolerant or seems to run out of energy faster than normal.
  • My horse has a mucoid or bloody discharge coming from one or both nostrils.
  • My horse has foul odor to his/her breathe, or the horse is dropping feed.
  • There is a large firm swelling on my horse’s face, around the eyes.
  • There is a swelling in in my horse’s throat latch region (firm or soft).
  • My horse has a decreased appetite.
  • My horse has a temperature greater than 101.5 F.
  • My horse has a respiratory rate > 24 breaths per minute or increased breathing effort.

Diagnostic Procedures/Equipment for Upper Respiratory tract

Digital Radiographs

Digital radiographs are used to assess the bony structures of the skull, including the teeth, in addition to assessment of the trachea and chest. It is important to note that more powerful x-ray generators are necessary to obtain diagnostic chest radiographs, and we are fortunate to have these more advanced capabilities. .

Digital radiograph

Ultrasonography

Ultrasonography is used to diagnosis soft tissue abnormalities.It is often used when assessing a horse for laryngeal abnormalities or lung disease (e.g. pleuropneumonia).

Video Endoscopy

This allows us to look at the horse’s upper respiratory tract. This procedure is performed while the horse is standing in the stocks or exam room. There is a small camera at the end of a flexible tube that is passed into the horse’s airway throught the nostril. The camera sends a picture to a large monitor, that is on a stand in the exam room, allowing the veterinarian, veterinary students, and owners to see what is going on inside the horse’s upper airway.

Video Endoscopy

Dynamic Endoscopy (need pictures)

Similar to video endoscopy, there is a camera at the end of a flexible tube containing fiberoptic cables that is placed through the horse’s nasal passage to view the larynx. However, unlike the video endoscope, the camera sends a picture to a small video screen, which is attached to a halter that is placed over the horse’s bridle. Once the endoscope is correctly position to view the larynx, the horse can be exercised to recreate the noise or exercise intolerance that the horse has been displaying. The purpose of the dynamic scope is to record what is going on in the horse’s upper airway while it is exercising at its normal level of performance. This diagnostic tool is frequently used in patients that are making noises while exercising or have exercise intolerance but are normal on standing video endoscopy. This system haseffectively replaced equine treadmills for diagnosing upper airway diseases under exercise.

We are willing to travel to race tracks, training tracks, arenas and stables to examine your horse with this game changing piece of equipment.

Computer Tomography (CT or CAT scan)

In regard to soft tissue surgery, the CT is mainly used to diagnosis dental disease and other abnormalities associated with the horse’s paranasal sinuses and skull. A CT scan uses radiation similar to a radiograph (x-ray), but the images are much more detailed and allow us to evaluate the anatomy in multiple different planes and even in 3D reconstructions. We have used the CT to diagnosis dental disease not seen on radiographs, accurately predict the degree of involvement of paranasal sinus disease, and to more accurately predict the prognosis for recovery for patients with temporohyoid osteoarthropathy. The CT scan requires that the horse be placed under general anesthesia for ~30 minutes, similar to that of a routine castration. The CT scan is not painful for the patient, but general anesthesia is required to keep the patient perfectly still during the exam.

Computer Tomography

Magnetic Resonance Imaging (MRI)

MRI uses a strong magnetic field, produced by a large magnet, to generate a very detailed image of the bone and soft tissue in a specific region of an animal’s body. The patient is placed under general anesthesia while the scan is being performed, and the part of the body to be imaged is placed within the magnet. The MRI scan is in no way painful for the animal, but general anesthesia is still required to keep the patient perfectly still during the exam. An MRI scan can take 90 minutes to 2 hours to complete. The benefit of a MRI scan vs a CT scan is the increase in soft tissue detail seen with the MRI.

TOMOtherapy Machine

TOMOtherapy is used to treat neoplastic lesions (cancer) in animals, including horses. This machine combines CT imaging with targeted radiation therapy. The horses that received this therapy are placed under general anesthesia for treatment, as the machine uses CT imaging to specifically target the tumor while sparing the adjacent healthy tissuse. The duration of the treatment session and the number of treatment sessions can vary depending on the lesion size and location.


Specific Diagnosis for upper respiratory tract diseases

Disease of the pharynx and larynx

  • Idiopathic laryngeal hemisplasia (AKA paralyzed flapper)
  • Arytenoid chondritis
  • Dorsal Displacement of the Soft Palate
  • Epiglottic Entrapment
  • Subepiglottic cyst

Paranasal sinus disease

  • Primary sinusitis
  • Secondary sinusitis
  • Ethmoid Hematoma
  • Sinus Cyst

Hernias

  • Abdominal hernia
  • Inguinal Hernia