Asthma in Cats

Are some cats more likely to get asthma?

Asthma is most common in cats from two to eight years of age. Overweight and obese cats are reported to be at greater risk for developing respiratory disorders. Siamese cats seem to have an increased risk of developing asthma and bronchitis, and some reports indicate that it is more common in female cats.

What are the clinical signs of asthma and bronchitis?

The most common signs of asthma / obstructive respiratory disease are coughing and respiratory distress. For example the cat may show difficulty breathing, shortness of breath and open-mouth breathing. Coughing is significant since there are relatively few causes of coughing in the cat. Many cats may stand or sit with their backs arched, elbows out and neck extending (this is called an orthopneic posture). Wheezing is easily heard with the stethoscope and is sometimes so loud that it can be heard by the owners. Occasionally, sneezing and vomiting are noted.

You should contact your veterinary surgeon immediately if your cat has an episode of open-mouth breathing.

What causes asthma?

The small airways (bronchi and bronchioles) may react to a number of stimuli, such as:

• Inhaled irritants - dust from cat litter, cigarette smoke, perfume or hairspray, and carpet fresheners.
• Pollens or mould, house dust mites, and dander (from other pets or even people)
• Infectious agents - viruses, bacteria
• Parasites - lungworm

How is asthma diagnosed?

A number of tests may be required to diagnose allergic lung disease in the cat.

The minimum diagnostic tests undertaken usually include haematology (looking at red and white cell counts), biochemistry (to check organ function) and sometimes faecal examination and urinalysis. One particular type of white blood cell, the eosinophil, is commonly associated with allergic events or parasitic disease. Elevated eosinophil numbers support a tentative diagnosis of asthma. In some cases, special tests will be performed on faeces samples, looking for evidence of lungworms.

Your vet may choose to test for Feline leukaemia (FeLV) and feline immunodeficiency virus (FIV) which can be associated with respiratory disease.

Thoracic radiography (chest X-rays) may show characteristic radiographic changes in the lungs in many cases of feline asthma or obstructive lung disease. X-rays may be suggestive of lungworm, and can be helpful to eliminate other types of heart and lung disease.

Bronchoscopy – examination of the airways of the anaesthetised cat with a small fibre-optic scope may be considered. During this examination samples of the mucus lining of the bronchi may be obtained with a small cytology brush. This sample can be examined under a microscope or sent for bacterial culture.

Tracheal lavage - a small amount of sterile saline can be flushed into the airways and retrieved, providing samples of material from deep in the lung. This material may be cultured for microorganisms and examined under the microscope.

In some cases, an underlying cause cannot be identified, despite a complete and thorough diagnostic work-up. Even when the underlying cause is not identified, many cats can achieve a good quality of life with medical management.

If it is not possible to complete a full diagnostic workup it may be acceptable to treat the cat with a course of steroids ("cortisone”). Many asthmatic cats respond favourably to this treatment with few side effects. However, caution is required in undertaking ‘trial treatment’ without definitive diagnosis since steroids can worsen bacterial infections; therefore, prophylactic antibiotics may be prescribed in cases where a work-up cannot be performed.

How is asthma treated?

The management of feline allergic lung disease is medical, and may involve one or more of the following therapies:

Avoidance of any factor known to trigger or aggravate breathing problems. This may mean trying different brands of cat litter, eliminating cigarette smoke from the home, avoiding carpet cleaners etc. It is important to pay close attention to environmental factors that may aggravate or worsen the condition.

Bronchodilators - These drugs are used to open up the airway and allow the cat to breathe more easily.

Corticosteroids - Glucocorticoids decrease inflammation, and as a result help in dilating the airways, and decreasing mucus production. In many cats, they are given daily. If the cat will not tolerate daily tablet administration, long-acting injections may be considered. Long term steroid therapy may cause some side effects and should not be withdrawn abruptly or given without careful monitoring.

An asthma attack may require emergency treatment at your veterinary surgery and require the use of bronchodilators, oxygen cage therapy, rapid-acting glucocorticoids, and adrenalin.

Will my cat be cured of asthma?

Cats with asthma / obstructive lung disease are rarely cured and often require lifelong medication. Sometimes a "cure" may be achieved if a specific underlying cause can be identified and treated. The goal of treatment is to lessen the severity and frequency of the "attacks" and improve the overall quality of life for your cat.