Tracheal Collapse in Cats
Tracheal collapse may affect the part of the trachea that is located in the neck (cervical trachea), or it may affect the lower part of the trachea, located in the chest (intrathoracic trachea). The trachea is the large tube that carries air from the nose and throat to the small airways (bronchi) that go to the lungs, and collapse of the trachea describes a condition in which the tracheal cavity (lumen) has narrowed during breathing, making the process of breathing difficult to accomplish.
Though tracheal collapse is rare in cats, it can affect cats of any age or gender.
Symptoms and Types
Symptoms of tracheal abnormalities seem to be aggravated by heat, excitement, exercise or obesity. The following symptoms are commonly observed in affected animals:
- Dry honking cough
- Difficult breathing
- Retching, attempting to vomit
- Abnormally rapid breathing
- Abnormal breathing sounds
- Unable to perform routine exercises
- Bluish colored membranes
- Spontaneous loss of consciousness
- Congenital - existing at birth
- Chronic disease involving the airways
- More common in obese or in those animals dealing with respiratory infection or airway obstruction
You will need to give a thorough history of your cat's health, including a background history of symptoms. After taking a detailed history, your veterinarian will conduct a complete physical examination on your cat. The routine laboratory tests will include a complete blood count (CBC), biochemistry profile, and urinalysis. The results of the complete blood count may show an abnormally high number of white blood cells (WBCs), indicative of infection.
Diagnostic imaging is an essential part of the diagnostic process, since the lungs and trachea will need to be examined as completely as possible. Chest X-ray remains a valuable tool, and may reveal a collapsed trachea as well as to help your veterinarian find the location of collapse. In some cases, enlargement of the right side of the heart may also be found.
Fluoroscopy, another advanced diagnostic technique, but one which can provide real time, active images of the internal body, may also be used for your cat. Fluoroscopy works by using an X-ray device placed in front of a fluorescent screen, with the patient on the other side of the screen, so that the physician can see the internal structure in motion, allowing for a more refined image and a more accurate assessment and diagnosis.
Your veterinarian may also take a tissue sample from the inside of the trachea for laboratory testing. This sample will be used to grow the bacteria in the tissue in order to determine if there is any harmful bacteria present in the tracheal tube, and conduct culture testing to see the types of cells that are present in the sample.
In order to grade the severity of the collapse, another technique called bronchoscopy can also be used. In this procedure, the bronchoscope, a tubular instrument with a camera attached, is threaded into the trachea and the images are retrieved and relayed onto video equipment where they can be reviewed and assessed in the process of making the diagnosis. Bronchoscopy is a more invasive method than the standard X-rays, but it can give a much more detailed view of the various abnormalities present in the tracheal tube, including foreign bodies, bleeding, inflammation, or tumors inside the airways. Bronchoscopy can also allow for estimating the degree of narrowing in the trachea, which may range from a grade-1 to grade-6 degree, measured on the basis of increasing severity. The bronchoscope can even be used to collect tissue and fluid samples from deeper within the tracheal canal for laboratory testing.