What is Paralysis of the Larynx?
With no muscle to pull back the walls of the larynx, when the cat inhales the walls can get sucked into the opening. In severe cases, the walls close and block the airway, leading to a total obstruction. This is a medical emergency as the cat will start to suffocate. Cats who suffer from larynx paralysis often go into respiratory distress and need stabilization to survive. A paralyzed larynx can also lead to overheating, as thermoregulation (panting) is hindered. Due to their larger size of larynx, males are more prone to this condition. If your cat is older, you may mistake paralysis of the larynx as a natural decrease in energy, when in fact your cat is struggling to breathe.
The larynx is a muscular portion of the respiratory tract where the vocal cords are housed. It is a part of the airway passage to the lungs. The trachea pulls the larynx open from two sides when a cat inhales, and relaxes upon exhale. The muscle responsible for this function is called the cricoarytenoideus dorsalis. If something damages the nerves that cause this muscle to operate, the larynx can become paralyzed. As there are two walls that are pulled during regular larynx function, this condition can happen to one or both sides.
Symptoms of Paralysis of the Larynx in Cats
Early symptoms often manifest as increased breathing noises. Late signs of the problem include extreme stress and the inability for the cat to catch its breath. All symptoms to watch for include:
- Harsh breathing noises
- Inspiratory stridor (high pitched creaking sounds while breathing)
- Raspy meow
- Dysphonia or total lack of voice
- Dyspnea (difficulty breathing)
- Intolerance to exercise
- Expanding chest
- Pulled back lips
- Dark or purple coloration of the tongue
- Wide eyes
- Limb weakness
- Aspiration pneumonia
Causes of Paralysis of the Larynx in Cats
There are a few different possible causes of larynx paralysis in cats. In rare cases, the cause remains unknown. Obesity is known to make the condition far worse. All known causes are listed below.
- Benign or malignant tumors of the neck or thorax
- Congenital birth defect
- Chronic injury to the nerves of the larynx
- Neuromuscular disorders
- Consumption of toxic substances
- Metabolic syndrome
Diagnosis of Paralysis of the Larynx in Cats
If your cat begins to show signs of respiratory distress, bring it to a veterinary clinic or animal hospital immediately. You will need to provide the veterinarian with your cat’s full medical history. The vet will complete a physical examination on the cat, palpating the neck area for abnormal lumps. The veterinarian will also perform a neurological examination, which includes assessing the function of all cranial nerves and examining normal movement of the cat.
Full blood work will need to be run including a complete blood count and a biochemical profile to check for any abnormalities. An X-ray of the neck and chest may be needed to confirm if any tumors or foreign bodies are present, or to see if aspiration pneumonia is setting in. Cancer can mimic signs of paralysis, and should be tested for. A laryngoscopic and endoscopic examination of the glottis and the larynx should be performed. The cat may need to be mildly sedated, with all reflexes still intact, while the larynx function is observed. Thyroid levels should also be measured.
Treatment of Paralysis of the Larynx in Cats
Respiratory distress will be managed before the underlying problem is addressed. Paralysis of the larynx can be hard to treat in cats due to their small airway passage.
The cat will be given general care to improve its ability to breathe before any other treatment is administered. This often includes supplementing the cat’s oxygen, cooling its temperature, sedation, and in some cases, assisted breathing and feeding tubes.
Surgical Airway Relief
Sometimes it is necessary to surgically alter the larynx to restore breathing ability. If an obstruction exists, it must be removed. A suture may be placed between cartilage in the larynx to allow the walls to properly move and separate again. Sometimes a minimally invasive “tie back” surgery will be performed, where only one wall is pulled open and secured to limit food and fluids from entering the lungs while allowing some airflow. This requires a small 3-4 inch incision on the neck. General anesthesia is required for all surgical procedures.
A tube may need to be temporarily placed through the trachea to allow airflow until the body begins to recover. Sometimes a hole is made through the neck to enable breathing. This is referred to as a tracheostomy.
Recovery of Paralysis of the Larynx in Cats
It is imperative that all postoperative at-home care instructions are properly followed. The incision should be kept clean. You will need to monitor it daily to ensure no signs of infection are present. Do not allow the cat to scratch at the incision site. Activity should be limited during the healing process. Oxygen supplementation may be needed for some time after the procedure. Seromas (fluid under the incision) also need to be watched for. Painkillers and any other medications should be administered as prescribed.
You may need to switch your cat to soft foods while the larynx heals. Your veterinarian may recommend a weight loss diet to help your cat if it is obese. Aspiration pneumonia may develop up to a year after the procedure if food or vomit gets into the lungs of the cat. This needs to be dealt with immediately, as it can be fatal. If the cat has not already lost its voice, it may lose it post surgery. Often cats do survive this procedure, with a success rate of over 80 percent. Many owners report that some youthful vigor is restored to their cat after paralysis of the larynx has been treated.