Tracheal Collapse: A Common Cause of Canine Coughing
“My dog can’t stop coughing, and I’m not getting any sleep!” What veterinarian hasn’t heard this complaint? Many different disorders cause coughing in dogs. One at the top of the list, particularly in smaller breeds, is a disease called tracheal collapse (aka, collapsing trachea).
Normal tracheal anatomy and function
The trachea is part of the upper respiratory system. Also known as the windpipe, it transports air from the nose and mouth down into the lungs, and then back again. The trachea is made up of rings of cartilage that are aligned side by side to maintain a smooth cylindrical shape that creates minimal resistance to airflow. (Visually speaking, the trachea looks like a tiny corrugated culvert pipe that you would find at a building supply store.) The entrance to the trachea is the larynx, a structure also comprised of cartilage, which opens during breathing and closes during swallowing. This clever design prevents inhalation of food material.
The inside lining of the trachea contains millions of fine cilia. These microscopic hairs trap any foreign material particles that are inhaled. Using a coordinated sweeping action, the cilia then transport these particles, often embedded in mucous, up to the throat where they can be disposed of via coughing or swallowing.
An inherited defect in the tracheal cartilage is thought to be the major player in the development of tracheal collapse. Imagine the normal “O” shaped tracheal cylinder collapsing in on itself, resulting in a “C” shaped internal lumen. This is problematic, not only in terms of airflow in and out of the lungs, but also in terms of removal of inhaled debris. Best-case scenario, the collapse causes some airway resistance-induced coughing. Worst-case scenario, it results in obstruction of airflow.
The collapse can occur throughout much of the trachea or only in a small section. The collapse tends to be a dynamic process- it is more pronounced during inhalation or exhalation, depending on which portion of the trachea is affected.
Any time the body’s normal anatomy is disrupted, the stage is set for secondary issues to arise. Not surprisingly, many dogs with tracheal collapse have concurrent respiratory tract infections.
Dogs at risk
Small breed dogs are the “poster children” for this disease, particularly Yorkshire Terriers, Pugs, Pomeranians, Poodles, and Chihuahuas. Middle aged and older dogs are most commonly affected. Overweight dogs and those who live in households with smokers may be at greater risk.
Tracheal collapse invariably causes coughing, and it is classically described as sounding like a “goose honk.” While I’ve heard some coughing dogs sound like geese, it’s important to emphasize that the cause of a cough cannot be diagnosed based on the sound of the cough, and tracheal collapse is no exception. There’s plenty of overlap between the sounds and causes of canine coughing.
Tracheal collapse coughing tends to worsen in response to excitement, activity or exercise (when air is moving more vigorously through the trachea). The cough may be persistent, even to the point of occurring round-the-clock. Sometimes, there is audible wheezing, particularly during inspiration. Other symptoms associated with tracheal collapse can include lethargy, reduction in appetite, and decreased stamina.
At its worst, tracheal collapse causes labored breathing, purplish or bluish colored tongue and gums thanks to oxygen deprivation, and syncopal (fainting) or collapsing episodes. Tracheal collapse symptoms are easily exacerbated by exposure to smog, smoke, or increased temperature, humidity, or pollen.
Making the diagnosis
Beyond a thorough physical examination and basic blood work, shooting x-rays of the chest and neck to evaluate the full length of the trachea is the usual starting point in the diagnostic workup. Given that tracheal collapse is often associated with only inhalation or exhalation (not both), x-rays can miss the diagnosis. For this reason, fluoroscopy (like an x-ray but shot in movie mode) is the ideal diagnostic tool. Not only does fluoroscopy confirm the diagnosis, it demonstrates how much of the length of the trachea is involved. This is important when considering treatment options. Tracheoscopy (viewing the inside of the trachea with an endoscope) is sometimes recommended to confirm the diagnosis and gather samples to rule out an underlying respiratory tract infection.
While there is no cure for tracheal collapse, there are multiple management strategies. The goals of treatment are twofold: minimizing coughing and maintaining a good quality of life. Realistically, it is often difficult to eradicate the coughing altogether.
Weight loss can make a positive difference for obese dogs with tracheal collapse. Because this takes time, it is important to implement other strategies concurrently. It’s a no brainer that dogs with tracheal collapse and cigarette smoke exposure have a lot to gain by lifestyle changes made by their beloved humans.
Avoidance of known environmental factors that precipitate coughing (heat, humidity, smog, etc.) can make a big difference. Replacing the neck collar with a chest harness eliminates external pressure on the trachea.
It’s almost always necessary to rely on medications when managing dogs with significant tracheal collapse symptoms. For some dogs, only short term or intermittent use is needed. Other dogs thrive only when medications are given long-term if not lifelong.
Medications are used for the following purposes:
Antitussive therapy (cough suppression): For dogs with collapsing trachea, coughing begets more and more coughing. (Think about the coughing you do after inhaling a small food particle into your windpipe!) And, once a vicious coughing cycle begins, it can be huge challenge to interrupt. Often, more than one antitussive medication must be tried to find just the right just the right recipe to quiet the cough.
Control of secondary inflammation: Anti-inflammatory medications are sometimes needed to control the inflammation associated with the tracheal collapse. Until the inflammation settles down, it can be difficult to control the coughing.
Treatment of secondary infection: Antibiotics are often indicated as tracheal collapse sets the stage for secondary bacterial infections within the respiratory tract.
Sedation and/or reduction of anxiety: Severely affected dogs may suffer from chronically interrupted sleep and/or anxiety induced by constant coughing and labored breathing.
In severe cases of tracheal collapse, a day or two spent within an oxygen cage may help turn a corner. Such oxygen therapy requires access to a 24-hour hospital and round-the-clock supervision.
When medical treatment fails to restore a good quality of life, placement of a tracheal stent is a reasonable consideration for some dogs. The stent is made of a metallic alloy. Using fluoroscopy (see above) the collapsed stent is placed within the area of tracheal collapse. Once deployed, the stent expands to support the tracheal walls. While this procedure can make a hugely positive difference in severe cases of tracheal collapse, not every dog is an ideal candidate. There can be problems associated with anesthesia as well as complications caused by the stent.
There are surgical techniques that involve placement of support rings around the outside trachea. The goal is to provide structural support. This is an aggressive procedure that can be fraught with complications. With the increasing popularity of tracheal stents, this type of surgery has, for the most part, fallen by the wayside.
The prognosis for dogs with tracheal collapse varies from excellent to awful. The outcome depends on the degree of collapse, which portion(s) of the trachea is involved, and the dog’s individual response to medication.
If your dog develops tracheal collapse, a veterinary specialist might just become your dog’s new best friend. The best way to diagnose tracheal collapse is via fluoroscopy (see above), a piece of equipment used almost exclusively by veterinary specialists.
The more finesse and experience a veterinarian has using medications to treat tracheal collapse, the greater the likelihood of a positive outcome, particularly in severely affected dogs. A veterinarian who specializes in internal medicine will have lots of experience treating this disease. Lastly, a highly specialized skill set is necessary for success with placement of stents, in terms of patient selection, stent selection, and accurate deployment of the stent. I strongly encourage seeking help from an internist if a really good response to initial treatment for tracheal collapse isn’t observed. Ask your family veterinarian for referral.
Do you have a dog with tracheal collapse? If so, what kind of dog do you have and what has been the response to treatment?
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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