Author: Dr. Joi Sutton, DVM
Date: August 15, 2013
There are times in all of our lives when we just cringe upon entering a situation. We veterinarians pick up a patient chart for the next exam and react internally. If it says "New puppy exam" we smile and gleefully enter the exam room. "Vomiting for 4 days" doesn't typically bring about a happy response. "Asthmatic cat urinating a lot" makes us want to crawl under a rock. Or, "Diabetic cat now coughing" might also send us running in the opposite direction. "Why"? Well, feline asthma is treated with steroids and steroids can cause insulin resistance. You see our dilemma. Today I'd like to discuss treatment options if your cat has feline asthma.
Feline asthma is a lifelong disease that can be severe or mild, and it typically waxes and wanes over time. Feline asthma is much like human asthma. It's a hypersensitivity reaction to allergens, dusts, smoke, aerosols, fumes, etc. The clinical presentation of an asthmatic cat is typically a cat who coughs, usually a deep, dry cough. It can then progress to all out respiratory distress as the airways constrict and the cat can't catch it's breath. The 3 main treatment options are modifying the environment to eliminate the stimuli, steroids and bronchodilators.
Just a few months ago we ran a series of newsletters about itchy pets and ways that we can avoid or limit steroid use for dogs and cats with food allergies and hay fever. Those of us trying to regulate diabetic patients know that steroids cause insulin resistance, and good glucose regulation is difficult when a pet is on steroids. Steroids can also cause immunosuppression, GI upset, liver or kidney disease, congestive heart failure, and drinking and urinating excessively.
Feline asthma can be even more troubling than food allergy or hay fever because steroids are integral to the treatment of feline asthma. Although we do our best to integrate bronchodilators and environmental avoidance of the triggering agents, steroids break the cycle of airway inflammation in addition to decreasing the allergic response. It is the airway inflammation that causes the clinical signs and results in remodeling of the airways.
The most commonly used bronchodilators for cat asthma are terbutaline, theophylline, aminophylline, and albuterol. Bronchodilators do not control inflammation, so they should never be used as the sole therapy without steroids. Inflammation of the airways causes irreversible changes. Bronchodilators ease respirations and are integral to the treatment of feline asthma. These bronchodilators can come in oral, injectible and inhaled forms. The long-term route of administration for bronchodilators is typically by mouth. Inhaled bronchodilators (ie albuterol) are typically reserved for situations of respiratory distress as they can add to airway inflammation which is the enemy for asthmatic cats. Inhaled bronchodilators shouldn't be used more than a couple times per week for cats. If a cat is having frequent episodes of asthma, then further investigation for possible infections or altering the steroid dose is indicated.
So if we must use steroids for an asthmatic cats during their episodes, how do we minimize the systemic effects of steroids? We try to avoid long-acting steroid injections because they are more likely to cause the adverse effects. Additionally, with long-term injectible steroids we aren't able to tailor the dose day to day. Once you give a long-lasting injection it is in the cat until it is metabolized. We can tailor the dose of steroids when given by mouth, so many asthmatic cats are on prednisolone during flare ups. The latest and greatest trend is to use inhaled steroids (ie Flovent) because inhaled steroids result in far fewer systemic effects compared to oral or injectible steroids.
If you are wondering how we get a cat to cooperate with an inhaler, there are several nifty gadgets created to facilitate this issue. They consist of a chamber with a hole fit for the inhaler on one end and a soft rubber kitty face mask on the other end. Since we can't tell our feline friends to breathe in and out deeply, we fill the chamber then gently hold the mask to the cat's face while it breathes in the aerosolized medication. The best known of these products is called the AeroKat.
I suspect that there are more asthmatics that end up with diabetes secondary to insulin resistance caused by steroids than diabetic cats who happen to be asthmatic. Nonetheless, if your cat is in either of these categories, speak with your veterinarian about inhalers if you aren't already using them.
NOTE: Consult your Veterinarian first to make sure my recommendations fit your pet's special health needs.