Feline asthma is also known by the terms bronchitis, reactive airway disease, and allergic lower airway disease.  It is a disease in cats affecting the smaller airways that branch off the windpipe (trachea).  These branches or air tubes, called bronchi, allow the transport of air into and out of the lungs.  When the bronchi become obstructed because of constriction or contraction 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 body.  Asthma, in people, specifically refers to the reversible constriction of the muscles in the bronchi.  Some cats have true asthma, whereas others have bronchitis.  Bronchitis is associated with inflammation and swelling of the walls of the bronchi causing a narrowed passageway.  Mucus plugs can also form reducing airway lumen diameter.  Bronchitis can be acute (short duration) and associated with reversible changes in the airway or chronic (longer term) and associated with permanent, irreversible changes in the airways.  Bronchitis (airway obstruction due to inflammation/swelling) and asthma (airway obstruction due to constriction of airway muscles) can occur at the same time.  They can be caused by bacterial infections, parasites, allergies or inhaled irritants.  In many cases, the underlying cause may not be identified.

The most common signs of bronchitis and asthma in cats include wheezing, coughing, or difficulty breathing.  The cough can mimic vomiting and some owners state the cat is acting like it wants to throw up a hairball.  Severity can vary from mild to severe.  If your cat is demonstrating markedly increased effort to breathing, open mouth breathing, nostril flaring or an inability to lay down comfortably, immediate veterinary attention must be sought.  These signs are not specific for asthma or bronchitis but can represent a life-threatening condition.

The diagnosis of feline asthma or bronchitis is usually approached initially with chest radiographs.  These are helpful in ruling out other diseases causing the same symptoms.  Further testing may include oxygen levels, tracheal wash, bronchoscopy or lung culture depending upon an individual’s response and severity.  It is important to check for heartworm disease.  Underlying causes such as fungal, bacterial, protozoal, parasitic infections should be ruled out depending upon geography and prevalence.

Treatment is somewhat dependent upon severity.  The less severe cases can be managed as outpatients.  The more severely affected patients require initial hospitalization.

First, any underlying disease (infection, heartworms, etc) must be identified and treated.  Changes in the cat’s environment are very important.

Second, it is strongly recommended that all exposure to cigarette smoke, other smoke (fireplace, incense, etc), dusts (cat litter, carpet powders, grooming/flea powders), and sprays (such as insecticides, hair spray, perfumes, cleaning products, air fresheners, fabreze) be eliminated.

Third, weight reduction in obese cats must be performed albeit carefully and slowly.  We do not want an overweight cat to go without eating for days as this can cause liver problems.

Fourth, medications consisting of anti-inflammatories, bronchodilators, plus treatment for underlying disease is generally needed.  Oxygen therapy is required in critical patients.  Some veterinarians feel that any disease with a potential allergic/immune component should be fed an elimination diet in case the dietary antigens are contributing to the allergic response.  An elimination diet is one based upon a protein and carbohydrate that has never been experienced before by that individual.  Dietary trials require that only that food and no other treats, supplements, etc be given exclusively for a period of 8-10 weeks.

The prognosis is quite variable.  If the underlying cause can be identified and eliminated, the prognosis is improved.  If permanent damage to the airways has occurred, the disease can not be cured.  The goal in the balance of patients is control of clinical signs with the above measures to reduce symptoms and prevent further deterioration of the airways.  Some cats suffering severe asthma attacks can die despite intensive medical efforts.