*The following information has been provided by Dr. Phil Zeltzman, a board-certified veterinary surgeon from Whitehall, Pennsylvania as a courtesy to goodnewsforpets readers. The following article is only for the sharing of knowledge and information; it is not intended to replace consultation of a veterinarian or other qualified pet care professional. To subscribe to his newsletter,here.
I have hardly ever dedicated a newsletter to a specific condition. Why? When I write about “how to pay for vet care” or “how to cope with euthanasia”, one would hope that most subscribers would be interested.
But if I write about spays, most owners of a male pet won’t even open the newsletter. If I write about cats, most dog owners won’t bother. And they’ll miss out, because I always try to include something that is relevant to them.
So today’s topic, laryngeal paralysis, is a notorious exception for a number of reasons:
- It’s an important topic.
- It is common in Labs, and we have many subscribers who own Labs — family pets, couch potatoes or Search And Rescue dogs.
- Many owners of dogs that are at risk have never heard of the disease.
- We have seen many laryngeal paralysis patients lately.
- I have promised to write about laryngeal paralysis to many clients and readers. So today, I keep my promise.
I hope that cat and small or medium breed dogs will read this, as we occasionally see laryngeal paralysis in those pets.
Anyway, let’s move on. As a reminder, for longtime and newer subscribers, including my Yahoo buddies, what follows is COPYRIGHTED.
What is Laryngeal Paralysis?
Laryngeal paralysis is condition that severely affects a pet’s breathing.
In the veterinary world, we tend to call it “Lar Par”, so that’s how we’ll call it in this newsletter. Yahoo group members (more on that below) tend to call it “LP.”
The larynx (please note, it is larynx and not “lar-nynx” as many people call it…) is the medical name for the voice box. If you’ve ever had laryngitis, then your very own larynx was irritated. The larynx is also the entrance to the wind pipe (or trachea) and beyond, to the lungs.
Besides making all kinds of noises, the job of the larynx is to close off after we inhale, open up when we inhale, and again shut off when we eat and drink so we don’t “swallow the wrong way.”
When laryngeal paralysis occurs, none of these things happen. Taking a deep breath becomes impossible. The dog’s voice may also change.
Who can be affected?
The typical patient is an older large breed dog. The poster child is the Labrador. Other common breeds include Golden Retrievers and Setters.
Males are affected 2-4 times more often than females.
There is a hereditary or congenital form of Lar Par, which can affect Bouviers des Flandres, Huskies and Dalmatians. In those rare cases, young dogs are affected.
Lar Par has also been described in cats.
Lar Par occurs because the nerves that control the muscles which act on the cartilage of the larynx are diseased.
Typically, the condition starts on one side (“unilateral” paralysis or hemiparesis). If your dog is an athlete (racing, agility, serious hiking, Search And Rescue), you may notice breathing difficulties. But if your dog is a family pet or a couch potato, you probably won’t notice much.
Only when the condition affects both sides of the larynx (“bilateral” paralysis) will most pet owners realize that there is a problem.
What are the signs?
Lar Par is a very stressful condition to the patient — who obviously doesn’t understand what is going on. These dogs literally suffocate.
Typically, the signs are progressive. The dog pants without exercising, has a noisy and labored breathing, and gets tired quickly during regular walks. Owners may notice that their dog’s voice changes and sounds hoarse.
Unfortunately, because Lar Par most often occurs in older dogs, the signs are often blamed on old age and arthritis… which delays treatment.
Therefore, Lar Par patients are often presented to a vet when they are in real trouble, i.e. when they can barely breathe. This commonly happens as the weather becomes hot and humid. Overweight or obesity worsens the condition.
At worst, the condition can become life-threatening.
What causes Lar Par?
Most of the time, we don’t know. This is called “idiopathic” Lar Par.
Occasionally, we find an underlying cause, such as hypothyroidism (a lazy thyroid). This is somewhat controversial, since hypothyroidism is common in older Labs and Goldens anyway. That said, treating hypothyroidism will not correct the Lar Par. So we recommend treating hypothyroidism because of the other consequences, not because it helps or cures Lar Par.
Occasionally, Lar Par is due to trauma, cancer, generalized diseases of nerves or muscles, or previous surgery (on the trachea or the thyroid gland).
How does my vet know my dog has Lar Par?
An experienced vet or surgeon will suspect Lar Par the second they walk into the exam room. But to confirm the suspicion, an exam of the larynx under sedation is necessary.
Before this can be done safely (at least in our surgical practice), we perform full blood work and chest X-rays. The purpose of blood work is to ensure the safety of sedation and anesthesia, and to test for hypothyroidism. The goal of chest X-rays is to know whether the patient has aspiration pneumonia (more on this below). The same X-rays can show if the patient as mega-esophagus, ie an enlargement of the tube between the mouth in the stomach. Finally, these X-rays confirm that there is no hidden cancer in the chest.
Under “light” sedation, the mouth is opened and the larynx is observed. With Lar Par, the folds of the larynx will not open and close as the patient breathes in and out. The folds remain closed — paralyzed.
Light sedation means that it should be heavy enough so the mouth can be opened, but mild enough for the patient to breathe spontaneously.
What is the emergency treatment?
When a patient presents on an emergency basis, two important goals are to calm the patient, and allow enough oxygen to get on board.
This requires sedation (acepromazine is often the drug of choice). Oxygen can be delivered by many different ways.
My least favorite way of stabilizing a Lar Par patient in crisis is am emergency tracheostomy, although it may be the only option in a few cases.
If the patient’s temperature is really high from overheating, emergency measures are taken to lower it.
Once the patient is stabilized, surgery is the best treatment.
What happens in surgery?
The goal of surgery is to permanently open up the larynx to allow more air to get in.
There are two main types of surgery: intraoral (i.e. surgery is done via the mouth) and extraoral.
These days, most surgeons will choose the extraoral approach, i.e. surgery is done via the left side of the neck. Most often, they will typically do a laryngeal “tie-back” procedure, a.k.a. arytenoid lateralization, on ONE side.
Typically, surgery involves placing 2 heavy nylon sutures (i.e. permanent) to open up the left side of the larynx. Only one side (again, typically the left) is opened up to minimize the risk of aspiration pneumonia.
Doing surgery on both sides dramatically increases the risk of aspiration pneumonia… and is simply not necessary.
What is the outcome?
In good hands, the outcome is typically good.
Theoretically, surgery provides instant relief: The patient can finally breathe. Then of course (s)he needs to recover and heal after surgery.
Clients routinely worry about doing this surgery in their (typically) older dog.
My standard replies are:
- 1. Age is not a disease.
- 2. Lar Par is not a death sentence. It’s a bump along the road, which shouldn’t affect the patient’s life expectancy as long as they don’t get fatal aspiration pneumonia.
What are the complications?
We are about half way through this newsletter, sorry, the rest will be published in 2 weeks.