Pet Health: Collapsing Trachea in Dogs

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ILLUSTRATION: RICK KIRKMAN
A honking cough could be a sign of collapsing trachea.

Dear Andrea:

Our small dog has bad coughing spells, and sometimes we massage his throat to work him out of it. Is a weak muscle causing the problem?

H.M. Heath
Aztec, NM

Dear H. M.,

Many toy and miniature dog breeds suffer from a congenital disease known as collapsing trachea. Although they may be born with it, symptoms of collapsing trachea in dogs often don’t manifest until they are three to five years of age. Most of the dogs affected have dome-shaped heads and short necks. Historically most owners fail to notice any respiratory problems until the animals become excited, exercise, bark, or pull on the leash. Some incidents may be so severe that they cause the animals to arrest or faint.

The cough is a very deep “honking” due to the trachea or windpipe being malformed in such a way that its cartilage rings are somewhat flattened. Over the top of these cartilage rings lies a smooth muscle membrane, which tends to be somewhat loose instead of its stretched snug-like normal. This smooth, hanging membrane often interferes with the flow of air that moves down the trachea. In excited animals, the membrane may hang into the windpipe and become quite cumbersome, forcing the dog to cough.

While massaging the throat may help relax some dogs, it may also stimulate some sensory nerves, resulting in a slowing of the heart rate. This could be dangerous in dogs that already have respiratory problems, and may even cause cardiac arrest in certain pug-nosed breeds which have collapsing tracheas.

Your vet can run some tests, such as an electrocardiogram, and take x-rays to diagnose a collapsing trachea. Fluoroscopy, a type of imaging that uses radiographs taken over a period of time, is most helpful in detecting the problem. Unfortunately fluoroscopy is often found only at referral institutions, so ask your veterinarian about this procedure. Surgical therapy (placing a prosthesis in the trachea) is often reserved for chronic cases which are not responsive to any of the suggestions above.