The trachea is the passageway through which air enters the lungs. It starts at the larynx (voice box) and goes down the neck into the chest cavity (thorax) where it splits into two main branches (bronchi) to join the two lungs. In the dog, the trachea is composed of a cartilage ring that is about 275 degrees of a circle with a membrane completing the other 85 degrees on the top. In humans, the cartilage forms a complete circle around the trachea and keeps it from collapsing.
When a pet breathes in, he or she creates negative pressure in the chest by expanding the ribs and the diaphram. This action sucks air into the lungs. The negative pressure also pulls on the membranous portion of the trachea. In some breeds, particularly the tea-cup and toy breeds, such as Chihuahua, Poodles, Yorkies etc, the trachea has a tendency to collapse from this negative pressure. This is due in part from the small size of the trachea as well as inherent weakness in the cartilage rings of the trachea. To visualize what is happening, think about what happens to a paper straw when you suck on it. At first it allows the liquid to come up, but when it gets weakened, the sucking action may cause the straw to collapse.
When the trachea collapses, the membrane from the top may touch the bottom of the trachea and start a coughing reflex. Moreover, the collapsing causes the airway diameter to shrink and thus make it more difficult to breath. As a result, the pet may try to breath harder causing even more collapse and start a vicious cycle of coughing.
How do our veterinary hospitaldiagnose collapsing trachea?
Collapsing trachea is diagnosed with a combination of a through physical examination, x-rays of the chest and neck, and direct visulization of the collapsing trachea through the use of endoscopic equipment. Many pets with collapsing trachea problems may also develop heart problems, bronchitis and/or pneumonia and so a thorough workup is indicated.
How do our veterinary hospitaltreat collapsing trachea?
Treatment of collapsing trachea is dependant on the severity of the problem and the presence of contributing problems such as heart failure or pneumonia. In the simplest form a treatment, anti-cough medication may be prescribed. If the problem worsens, sometimes we have to add broncho dilators or steroid drugs to reduce inflammation. Finally, for the very worst cases, there is a surgical procedure to implant a plastic stent to help hold the trachea open during breathing. This surgery is not without complications and should be considered only after medical management is not working.
We always warn owners of dogs with collapsing trachea not to use any neck collars or leashes, to avoid excitement for their pets and to avoid heat stresses. In addition, it is important to pursue scrupulous oral hygiene because these pets are very prone to infection, which can come from the oral cavity,
What is the prognosis for collapsing trachea?
Collapsing trachea is a serious problem and can even lead to the demise of your pet. With early diagnosis and treatment, these pets can lead relatively normal lives but they are at increased risk of serious respiratory and cardiac problems. Pets with collapsing trachea should be examined twice yearly, have their teeth cleaned at least once yearly and have chest x-rays performed yearly.
Even with medical managment, some pets’ tracheas will continue to deteriorate. In these cases, a “stent” can sometimes be implanted in the trachea to help keep it open. This procedure can be performed at some specialty centers.