Dr. Arnold Plotnick, D.V.M., ASPCA, VP Bergh Memorial Animal Hospital
I was a senior in veterinary school, examining one of my hospital cases, when I heard a distinct honk from a nearby cage. Looking up, I saw “Cuddles,” a Yorkshire terrier, sitting with her neck extended, honking. She seemed uncomfortable, so I summoned a resident. By the time he arrived, however, Cuddles was sitting quietly. I assured him that not two minutes before, the dog had been honking like a goose. The resident glanced at Cuddles’ chart. “She has a collapsing trachea,” he snorted. “She’s supposed to sound like a goose!”
Tracheal collapse is a common cause of airway obstruction in dogs. The trachea, or “windpipe,” is a tube made up of sturdy rings of cartilage through which air is transported to and from the lungs. Sometimes, however, the tracheal rings begin to collapse, and as air is squeezed through, the characteristic honking cough results.
The Whys and Wherefores
Why tracheal collapse occurs is unknown, although a congenital abnormality, in which the cartilage of the tracheal rings is less cellular and therefore weaker than normal, is suspected. The condition, which is genetic, primarily affects toy breeds of both sexes, with Yorkies by far the most commonly affected. Collapsing trachea can manifest at any age, though the average age when clinical signs appear is six to seven years. Additional signs that may be seen include exercise intolerance, labored breathing and cyanosis (a bluish tinge to the gums). The cough and other signs may be provoked by excitement, eating, drinking, tracheal irritants (smoke or dust), obesity, exercise or hot and humid weather.
A honking cough in a toy-breed dog is highly suggestive of collapsing trachea, but a definitive diagnosis may require additional tests. X-rays may reveal an obviously collapsed trachea, although not always. Fluoroscopy, which allows visualization of the trachea as the dog inhales and exhales, may be necessary to confirm the diagnosis. Fluoroscopy is available only at universities and referral centers.
Most cases of tracheal collapse are treated with cough suppressants, bronchodilators, corticosteroids (to control inflammation) and/or antibiotics. In obese patients, weight loss helps decrease respiratory effort. Although treatment is not curative, a study released in 1994 showed that 71 percent of dogs treated medically showed a good long-term response.
If medical management produces no response in two weeks, or if severe signs compromise the pet’s functionality, surgery is recommended. Various surgical techniques have been described, but the application of prosthetic polypropylene rings to the outside of the trachea is the current treatment of choice, with an overall success rate reported to be in the 75 to 85 percent range. In general, the outcome of surgery is poorer for dogs older than six years. It is a tricky, specialized surgery that is best performed by a skilled surgeon, usually at a referral center.
Whether medical or surgical treatment is chosen, pet owners can help relieve signs by keeping their pet’s weight down (even slightly under ideal), switching from a collar to a chest harness and avoiding respiratory irritants. With good care and some luck, their home will once again be a no-honking zone.
Dr. Plotnick was former vice president of Bergh Memorial Animal Hospital.