What is laryngeal paralysis?

The term "laryngeal paralysis" is most commonly associated with animals, specifically dogs and horses. Veterinary medicine recognizes this condition as potentially serious, as it can cause interference with breathing to the point of emergency. In humans, a similar condition called laryngeal nerve palsy is recognized to cause similar problems. In either case, laryngeal paralysis simply refers to paralysis of the muscles of the larynx that normally contract and expand during breathing. In other words, the normal function of the larynx is disrupted by the inability of the muscles to function properly.

Laryngeal paralysis in animals is not particularly common, but occurs mainly in larger breed dogs. It may be an inherent condition that affects puppies, but most cases seem to point to the problem occurring in older dogs for largely unknown reasons. Paralysis can occur gradually over time, leading to trouble breathing and wheezing, and is often indicated by noisy breathing and obvious distress. Ultimately, the animal's difficulty breathing can lead to suffocation if veterinary treatment is not received, which may include oxygen, sedation, and intubation. Laryngeal paralysis in animals may or may not be corrected by surgery, and some animals will continue to suffer from an ineffective airway.

In humans, paralysis of the laryngeal nerve is usually the result of a tumor, cancer of the larynx, or a postoperative condition. In the case of postoperative laryngeal paralysis, this condition is associated with thyroid surgery, although it is considered a rare complication. Patients may have unilateral or bilateral laryngeal nerve palsy. Unilateral refers to only one affected side, while bilateral refers to both. Unilateral laryngeal nerve palsy, or unilateral vocal cord paralysis, may not be immediately apparent and may only present as hoarseness or a change in voice, but it worsens over days to weeks. In contrast, symptoms of bilateral laryngeal nerve palsy are more immediate and may include shortness of breath or aspiration.

To better understand what happens when part of the larynx becomes paralyzed, the anatomy of the larynx should be studied. As part of the respiratory system, the larynx acts as a passageway between the pharynx and the trachea. Laryngitis is the most commonly known inflammation of the larynx in humans, resulting in sore throat, hoarseness or loss of voice, and difficulty swallowing or pain. However, the inflammation present does not cause the muscles within the larynx to stop working as with laryngeal paralysis. For more information on this condition in animals, consult your veterinarian. For questions or concerns about the function of the larynx, or symptoms of conditions and diseases of the larynx, consult a doctor.

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