Also known as feline bronchial disease, allergic bronchitis, allergic airway disease and allergic asthma), asthma is a noninfectious respiratory condition that is characterised by acute constriction of the lower airways, resulting in coughing and respiratory distress. Asthma is one of the most common causes of respiratory diseases in cats, affecting around one in 100. Attacks may range from mild to severe and life threatening.
The condition is triggered by inhalation of an allergen. Common allergens include pollen, perfume, cigarette smoke, smoke from household fires, mould, household sprays (hairspray, air fresheners etc.) and dust from cat litter. Cats of all age and breed can be affected, however, Siamese tend to be over-represented which suggests a genetic predisposition. Obese cats are also at greater risk of developing asthma.
What happens during an asthma attack?
When an allergen is inhaled, the following occurs.
- The smooth muscles around the airways tighten and block the airflow.
- The walls of the airways swell and become narrower, blocking the airflow.
- The airways produce extra mucus, causing even more narrowing.
- Contraction and narrowing of the airways impedes air flow into the lungs.
What are the symptoms of feline asthma?
Difficulty breathing (dyspnea).
Sitting with the shoulders hunched over, neck extended with rapid open mouthed inhalations and exhalations (tachypnea).
Symptoms may be mild or severe. In mildly affected cats they may cough of wheeze occasionally. Severely affected cats may cough and wheeze daily, leading to airway constriction and open-mouthed breathing/panting. A severe asthma attack can lead to death.
How is feline asthma diagnosed?
Your vet will do the following:
- Listen to the cat's chest/breathing.
- Take a chest x-ray to look for signs of bronchial inflammation and enlarged lungs, flattened diaphragm and doughnuts.
- Tracheal wash or airway lavage to check for the presence of eosinophils (a type of white blood cell) and infectious organisms.
- Fecal flotation test to check for parasitic worm eggs.
- Complete blood count to check for infection and the presence of eosinophils.
How is feline asthma treated?
There is no cure for asthma, although in most cases it can be managed. Treatment may include:
Oral glucocorticoids may be prescribed to reduce inflammation. There may be side effects from long-term use of steroids such as diabetes, pancreatitis, increased urination, weight gain, behavioural changes. Traditionally, cats will be started off on oral steroids until a response is achieved and the cat's condition becomes stable. He is then tapered off this medication in switched to inhaler steroids.
Inhalant glucocorticoids. Same as above, they reduce inflammation. There is a relatively new inhaler system on the market called AeroKat, Flovent is the most commonly used inhalant steroid. Inhaled steroids generally don't get into the system as much as oral steroids, thus side effects are greatly reduced. Inhalant medications are administered by placing a mask over your cat's mouth and nose. Advantages are that the medication targets the airways directly.
Bronchodilators: These help open the airway at times of severe coughing or wheezing. The most common bronchodilator is albuterol (Proventil®, Volmax®, Ventolin®).
In an emergency, get your cat to the closest vet immediately. You will not be able to treat this at home. Your veterinarian will usually inject a corticosteroid to reduce inflammation and use a bronchodilator to help open the airway. Ephedrine may be given in a life-threatening attack.
Removing as many common triggers as you can from your cat's environment will be recommended to reduce exposure. This includes avoiding using scented products and airborne particles such as dust, smoking outside, switching to a dust free type of cat litter (silicone and paper pellets are low in dust).
Air purifiers and humidifiers can also reduce the number of attacks. Dry air is a known trigger.
Reduce stress in your home.
If your cat is overweight, a carefully monitored weight loss regime may be necessary. This should be monitored by your veterinarian as sudden weight loss can result in feline hepatic lipidosis.