Last week, a client brought in a 3-year-old, female, Siamese mixed breed cat who had a severe pet health issue. The cat had been coughing for 5 months. The coughing started out randomly, but had now progressed to multiple coughing attacks daily. She was coughing during her examination, and her abdominal muscles where heaving in and out in an effort to breathe. I diagnosed her with feline asthma, and with proper medications she is now breathing easily.
Feline asthma is a disorder that causes decreased airflow in the small airways of the lungs called bronchi and bronchioles. This airflow limitation generally is the result of some combination of airway inflammation, accumulated airway mucus, and airway smooth muscle contraction. Asthma in cats is sometimes also called feline bronchitis, but these are actually two separate disorders. However, the distinction between asthma and bronchitis is not made easily, and many times it is not possible to distinguish bronchitis from asthma in cats. They do share a common finding of chronic airway inflammation and hyper-responsive (over-reactive) airways.
Asthma affects about 1% of cats* and Siamese cats seem to be more susceptible. It usually starts between the ages of 2-8 years old. The most common symptoms in cats with asthma are wheezing and coughing. The coughing has been described as a dry, hacking cough that can be confused with retching or gagging. Many cats assume a squatting position with the neck held low and extended during these coughing episodes.
Mildly affected cats may cough only occasionally and appear to be normal otherwise. These early signs are often overlooked or are mistaken for hairballs. The frequency of coughing will increase with time in many cats, and the most severely affected cats have daily bouts of coughing and wheezing with severe airway constriction leading to open-mouth breathing and respiratory distress that can be life-threatening. Like humans with asthma, cats can die from an acute asthma attack.
The exact cause of the underlying airway inflammation and airway hyper-responsiveness in cats with asthma remains under investigation. It does appear that when the airway of the cat is sensitive to certain stimuli, exposure to these agents leads to a narrowing of the airways. The inciting agents are usually direct irritants to the airways or things that provoke an allergic response in the respiratory tract.
These agents can include inhaled allergens (dust from cat litter, cigarette smoke, perfume, hairspray, deodorizers), pollens or mold, infectious agents (viruses, bacteria), and parasites (heartworms, lungworms). Regardless of the irritating agent, the end result is the same: muscle spasm and constriction of the airways, build-up of mucus and airway inflammation.
Because feline asthma could occur in any cat, it’s a good idea to be prepared with cat insurance. After a thorough physical examination of your cat, your veterinarian will take chest x-rays to help diagnose asthma. Characteristic changes in the lungs are common on x-rays. Bloodwork may be run to help provide clues as to the underlying cause and to rule out other possible diseases like heartworm. In some cases, bronchoscopy and airway flushing are performed under anesthesia to visually examine the airways and obtain cell samples from deep in the lungs for microscopic examination and testing.
Asthma in cats can be treated successfully but not cured. The most important drug for treating feline asthma is a corticosteroid to reduce the chronic airway inflammation. The traditional method is to utilize oral corticosteroids which are given at a higher dose for about 10-14 days and then slowly tapered down to an every other day dosing regimen. Cats are much more resistant to the side effects of steroids than are dogs or humans, and most cats do quite well with low-dose, long-term steroid use. Bronchodilators may also be used to open the airways and allow the cat to move air more freely.
In recent years, veterinarians have found that the most effective cat health therapy for feline asthma may be to use inhalers like human asthmatics use. A mask and spacer system has been designed for use in cats similar to those used for babies and small children. Both corticosteroid and bronchodilator inhalers are available for cats. The advantages of inhalers are that the medication is delivered directly to the airways where it is needed, and they are associated with fewer long-term side effects than oral systemic steroids. The downside of inhaler therapy is that it can be expensive. Your veterinarian will help determine which treatment is best for your cat.
Any factors known to trigger or aggravate breathing problems should be avoided. This may include trying different brands of cat litter, eliminating cigarette smoke from the home, and discontinuing use of any aerosols or sprays in the home or using them well away from the affected cat. Air purifiers may also be helpful. In addition, obese cats with asthma will benefit from weight reduction.
