What are Laryngeal Paralysis?
Studies show that Thoroughbreds and Thoroughbred crosses are more likely to develop laryngeal paralysis. Infection and injury can also play a role in the development of this condition. If your horse is having noisy and labored breathing, it is important that he is seen by a veterinarian.
Laryngeal paralysis in horses occurs when the nerves or the muscles of the larynx stop functioning normally. The condition can affect one or both sides of the larynx. Laryngeal paralysis makes it difficult for the horse to breathe naturally, especially during exercise.
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Symptoms of Laryngeal Paralysis in Horses
Symptoms may include:
- Roaring sound during exercise
- Gasping for breath after exercise
- Exercise intolerance
- Heat intolerance
Causes of Laryngeal Paralysis in Horses
Causes of laryngeal paralysis may include:
- Trauma injury
- Guttural pouch infections
Diagnosis of Laryngeal Paralysis in Horses
Along with an overall condition evaluation of your horse which could include palpation of the abdomen, examination of lymph nodes, and verification of pulse and heart rate, your veterinarian will want to discuss recent injury, dietary changes, behavioral abnormalities, and symptoms you have noticed that prompted you to consider laryngeal paralysis.
Clinical signs may confirm the diagnosis, although additional testing may be needed. Tests may include the following:
- Complete blood count - Checks the count of platelets, red and white blood cells; infection or anemia may be ruled out
- Ultrasound Electromyogram (EMG) records the electrical activity made by the skeletal muscles
- Chest x-rays can help to rule out fluid in the lungs or pneumonia
An endoscopic exam is performed while the horse is at rest and then during exercise (on a high speed treadmill); the test has a 0-5 scale. If there is no breathing problem with the horse and the larynx is working properly, the rating would be 0. If the endoscope shows severe problems with the larynx and the horse shows distress while on the treadmill, the score would be 5. Moderate findings will score within the range of 1 and 4.
Treatment of Laryngeal Paralysis in Horses
Once your horse is diagnosed with laryngeal paralysis the veterinarian may prescribe corticosteroids and anti-inflammatory medications to help decrease inflammation in the larynx. Horses diagnosed with guttural pouch infections will be prescribed antibiotics. If the x-rays show fluid in the lungs, the horse will be treated with antibiotics.
The veterinarian may suggest surgery to help improve your horse’s ability to breathe and exercise. There are several types of surgeries for laryngeal paralysis, such as:
The most common surgical procedure, the paralyzed cartilage is tied back allowing the larynx to remain in an open position. General anesthesia is required for this surgical procedure.
The damaged ventricle is surgically removed to widen the airway. This procedure can be performed with laser surgery. General anesthesia may not be necessary.
Neuromuscular Pedicle Graft
This surgery is meant to help the nerve damage of the larynx. Nerves from the neck muscles are used to replace the damaged nerves around the larynx. General anesthesia is required for this surgical procedure.
Recovery of Laryngeal Paralysis in Horses
Usually the patient will be kept overnight for observation. Intravenous therapy will typically be utilized throughout the night; it is used to administer pain medication, sedatives and fluids to your horse.
Once the patient is released, the equine surgeon will give you a postoperative treatment plan. In most cases, the surgeon will prescribe antibiotics as a precaution against infections. Anti-inflammatory drugs will help with any inflammation. He may also recommend an antiseptic throat spray for the horse, to be used daily. Your horse’s diet will be restricted to soft food for the first few days after surgery.
If there was an incision made, the area will need to be cleaned and re-bandaged. Rest and very limited exercise are usually required for 3-6 weeks.
Follow up visits will be necessary to monitor your horse’s progress and also to remove sutures or staples. During the follow up visits, the veterinarian will evaluate when your horse can begin gradual exercise. Usually, a few months after the surgery the veterinarian may recommend repeating the endoscopic exam, bloodwork and x-rays.
Surgery procedures sometimes have postoperative complications. Contact your veterinarian if you observe:
- Coughing with or without blood
- Bleeding from the incision
- Open sutures
- Difficulty swallowing
- Labored breathing
In most cases, patients that underwent surgery for laryngeal paralysis, have a good recovery prognosis from the condition.