What is a collapsed trachea?
The trachea, also known as the windpipe, is an important structure which connects
the throat to the lungs. It serves the purpose of directing air into the respiratory
The normal trachea is tubular. It maintains its shape because of a series
of rings made of cartilage. These rings do not completely encircle the trachea.
They are 'C' shaped and run from 2 o'clock to 10 o'clock. The remainder of the
trachea is composed of a flexible membrane that joins the ends of the cartilage
rings. (Tie the tips of the C).
When the cartilage rings are flattened from the top to the bottom, the trachea
is said to be collapsed. Rapid inhalation of air can cause the trachea to flatten
and make it difficult for air to enter the lungs.
Why does it happen?
We do not completely understand how this condition develops. However, we know
that these dogs have an abnormality in the chemical makeup of their tracheal
rings. The rings loose their stiffness so they are not able to retain their
circular shape. We also know that it occurs in certain breeds of dogs, notably
Chihuahuas, Pomeranians, Shih Tzus, Lhasa Apsos, Toy Poodles, and Yorkshire
Terriers. Because of that, we suspect that there is a genetic factor involved.
What are the clinical signs?
The most common clinical sign is a chronic cough. It is often described as
dry and harsh and can become quite pronounced. The term "goose honk" is often
used to describe it. Coughing is often worse in the daytime and much less at
night. The cough may also begin due to excitement, pressure on the trachea (from
a leash), or from drinking water or eating.
How is collapsed trachea diagnosed?
A dog of the breeds listed above with a chronic cough, especially a "goose
honk" should be suspected as having collapsed trachea. Often very light pressure
over the trachea during the physical examination can raise a suspicion of collapsed
trachea in a small dog with a persistent dry cough. While the information gained
from the physical examination is helpful, other tests are needed to confirm
Radiographs (x-rays) of the chest can identify the trachea and its shape.
However, a collapsed trachea changes its diameter during the respiratory cycle.
It is usually collapsed during inhalation and normal during exhalation. Therefore,
we attempt to make radiographs during both phases of respiration. This is easy
in some dogs and rather difficult in others since dogs will not "Take a deep
breath and hold it."
Endoscopy is another way to visualize the trachea. An endoscope is a tube
that is small enough to insert into the trachea; the operator can see through
it and visualize the inside of the trachea. By watching the trachea during inspiration
and expiration, abnormal collapsing can be seen. Unfortunately, tracheal endoscopes
are expensive and not available at every veterinary practice.
Isn't coughing also a sign of heart failure?
Yes, it is. Many dogs with collapsed trachea will also have heart disease.
The heart is usually evaluated when carrying out the tests to diagnose a collapsed
trachea. Treatment for heart disease is not indicated unless an abnormality
How is it treated?
Collapsed trachea can be treated medically or surgically. Some dogs respond
well to bronchodilators and various types of anti-inflammatory drugs. The trachea
of these dogs is easily infected, so antibiotics are usually part of the treatment.
If obesity is present, weight loss is often beneficial. Excitement and vigorous
exercise are likely to cause a relapse, so they should be avoided as much as
Some dogs respond well to the medical approach, and others do not. Because
medical therapy only treats the symptoms and does not correct the problem, these
dogs are always subject to recurrences of coughing and breathing difficulty.
If medical therapy is not successful, the dog should be evaluated for possible
surgery. Radiographs and endoscopy are used to determine how much of the trachea
is collapsed. If the only abnormal part is that segment between the throat and
the point where the trachea enters the chest (the thoracic inlet), surgery may
be curative. However, if the segment of the trachea that is within the chest
cavity is abnormal, surgery is not likely to be helpful because that part is
not easily accessible to the surgeon.
There are several surgical approaches that have been used. Each approach implants
an artificial support device that is secured around or within the trachea. The
purpose of the support device is to hold the tracheal rings in their normal,
open position. Although some dogs have excellent results and are truly cured
of the disease, the outcome is not uniformly successful.
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