The horse’s respiratory tract is responsible to moving air from the atmosphere to the lungs and visa versa. The respiratory tract is divided into upper and lower portions. The upper respiratory tract is made up of the structures from the nostrils to the cervical trachea (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 both medically or surgically depending on the diagnosis. The key to treating any disease is to get an accurate diagnosis. Texas A&M is fortunate to be equipped with state of the art diagnostic equipment to assist us in getting the most accurate diagnosis.
Signs that my horse may have an upper or lower respiratory tract disease
- My horse makes noises while breathing, especially when exercising.
- My horse is exercise intolerant or seems to run out of energy faster than normal.
- My horse has a muciod 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 decrease appetite his/her appetite.
- My horse has a temperature greater than 101.5 F.
- My horse has a respiratory rate > 24 breaths per minute.
Diagnostic Procedures/Equipment for Upper Respiratory tract
Digital radiographs are used to identify fractures or abnormalities in bones and soft tissue swelling. Frequently digital radiographs are used to identify abnormalities in the paranasal sinuses, tooth abnormalities or bone abnormalities under wounds.
Ultrasonography is used to diagnosis soft tissue abnormalities. It can be used to diagnosis tendon and ligament sprains, pneumonia, abnormalities in the abdomen, and identify what soft tissue structures are involved in a wound.
This allows us to look at the horse’s upper respiratory tract. This procedure is done while the horse is standing in the stocks or exam room. There is a small camera at the end of a flexible tube that goes in the horse’s airway. 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. Based off the endoscopic exam we can tell if the disease in the upper airway is infectious, mechanical dysfunction, neurologic dysfunction or traumatic in origin.
Dynamic Endoscopy (need pictures)
Similar to video endoscopy, there is a camera in a tube that is placed in the horse’s nose 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. Usually the horse is tacked up in their normal saddle and bridle and then the halter containing the dynamic scope and video screen is placed over the bridle and secured to the horse’s head with 3 leather straps. Almost all horse’s tolerate the endoscope and halter quiet well. Once the endoscope is correctly position to view the larynx; the rider, jockey or driver is asked to exercise the horse 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 in the horse’s normal environment. This diagnostic tool is frequently used in patients that are making noises while exercising or have exercise intolerance, but are normal on video endoscopy. This system has in a lot of ways replaced the equine treadmills for diagnosing upper airway diseases. We are willing to travel to race tracks, training tracks and stables to examine your horse with this piece of equipment.
Computer Tomography (CT or CAT scan)
In regards to soft tissue surgery the CT is mainly used to diagnosis dental disease and other abnormalities associated with the horse’s skull. A CT scan uses radiation similar to a radiograph (x-ray), but the images are much more detailed, to assist us in getting the most accurate diagnosis and prognosis from your horse. We have used the CT machine 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 is placed under general anesthesia for 30 minutes and scan itself only takes 15 minutes. The CT scan is not painful for the patient, but general anesthesia is required to keep the patient perfectly still during the exam.
Magnetic Resonance Imaging (MRI)
The MRI machine uses a strong magnetic field, produced by a large magnetic, to generate a very detailed image of the bone and soft tissue in an animal’s body. The patient is under general anesthesia while the scan is being performed and the part of the body that needs to be imaged is placed within the magnet. The MRI scan does not hurt 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 ½ hours to complete. The benefit of a MRI scan vs a CT scan is the increase in soft tissue detail seen with the MRI.
This is a special device that is located in our imaging center, along with the CT and MRI machine. The TOMO machine is used to treat neoplastic (cancer) in horses. It uses a combination of a CT machine along with radiation therapy. The horses that received this therapy are placed under general anesthesia for treatment. The duration of the treatment session and the number of treatment session 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