Feline Bronchitis (“Feline Asthma”)

Feline bronchitis, commonly called feline asthma, is a disease
in cats affecting the smaller airways that branch off the
windpipe (trachea). These branches, called bronchi, allow the
transport of air into and out of the lungs. When the bronchi
become obstructed because of constriction or con-traction of the
muscles in the walls of these airways, the inflammation or
irritation of the airways, or excessive secretions that plug the
insides of the airways, the end result is an impaired ability to
bring oxygen into the lungs for delivery to the rest of the
body. Although the term “asthma” is commonly used to describe
this syndrome in cats, this term is somewhat misleading.

Asthma, in people, specifically refers to the reversible
constriction of muscles in the walls of the bronchi. Some cats
have true asthma, whereas others have bronchitis. Bronchitis is
associated with inflammation and swelling of the walls of the
bronchi that cause a narrowed passageway and airway obstruction
by plugs of mucus or other secretions, which also narrows these
tubes.

Bronchitis can be acute (short duration) and associated with
reversible changes in the structure of the airways or chronic
(long duration, usually more than 2 to 3 months) and associated
with permanent, irreversible changes in the airways.

Bronchitis and asthma can occur at the same time and can be
caused by bacterial infections, parasites, allergies, or inhaled
irritants; in many cases, the underlying cause cannot be found.

The most common signs of bronchitis in cats include constant,
cyclic, or seasonal coughing; difficulty breathing; and/or
wheezing. Episodes of coughing can mimic vomiting; some owners
think their cats are vomiting up hairballs when they are truly
having a coughing fit followed by retching. Breathing may be
rapid or require excessive effort; some severely affected cats
may breathe with their mouths open.

If your cat ever displays any of these symptoms, it should be
promptly taken to your veterinarian for further evaluation, as
these signs are a warning of potentially serious disease. These
signs are not specific for bronchitis and can also be seen with
many other diseases including heart failure, pneumonia, and lung
cancer.

In the diagnosis of feline bronchitis by your veterinarian, the
first test is usually to take a radiograph (x-ray) of the chest.

Second, your veterinarian may recommend obtaining a sample of
cells from the trachea and bronchi to examine under a microscope
and to culture for any infectious organisms.

It is also common to check the blood and feces for parasites
(heartworm and lung worm, respectively). There are several
principles to follow in the treatment of feline bronchitis.

First, any underlying disease (for example, bacterial or
parasitic infection) must be appropriately diagnosed and
treated.

Second, changes must be made in the cat’s environment, since
cats with bronchitis often have sensitive, hyperactive airways,
and inhalation of irritating particles from the environment can
cause worsening of their disease. Consequently, it is strongly
recommended that their exposure to smoke (cigarette or
fireplace), dusts (cat litter, carpet fresheners, flea powder),
and sprays (insecticides, hair spray, perfumes, and cleaning
products) be eliminated or minimized.

Third, weight reduction in obese cats should be attempted under
the supervision of a veterinarian. Finally, medication should be
given to treat the airway obstruction directly.

Two classes of drugs are commonly prescribed: steroids (such as
prednisone, dexamethasone, and methlyprednisone), and
bronchodilators (such as theophylline, aminophylline, and
terbutaline).

Bronchodilators help to dilate or open the airways by relaxing
the muscular walls. Common side effects of bronchodilators in
cats can include gastrointestinal upset, restlessness, and
lethargy.

Steroids decreases the inflammation and swelling of the airway
walls. Side effects in cats are uncommon but may include
behavioral changes.

It is important that your cat have regular rechecks with your
veterinarian, as the doses of the medications commonly need to
be adjusted. Prognosis is variable for this disease. If the
underlying cause can be identified and successfully treated or
eliminated, the prognosis is excellent. If permanent damage to
the airways has occurred, the disease cannot be cured. With
proper medical management, clinical signs can be controlled and
the damage to the bronchi can be stopped or slowed.

Some cats suffering severe asthma attacks can die despite
intensive medical efforts.

The above is general veterinary information. Do not begin
any course of treatment without consulting your regular
veterinarian. All animals should be examined at least once every
12 months.