What is feline asthma?
Feline “asthma” and feline bronchial disease are respiratory conditions that are encountered frequently in cats. These disorders can be responsible for chronic coughing, wheezing, loud or rapid breathing, and loss of play activity. In severe cases life-threatening respiratory distress may occur. The disease syndrome is associated with activation of inflammation (irritation) in the lungs in response to irritants or allergens in the environment. The cells in the lung respond to the insult by increasing the production of mucus and triggering constriction (narrowing) of small airways. These responses lead to symptoms in affected cats.
In most cats, the cause of disease goes unrecognized. However, trigger events and environmental history should be investigated. In particular, exposure to smoke-contaminated rooms, aerosol sprays or cleaners, and dusty or perfumed litter should be considered; recent upper respiratory infection with sneezing or nasal discharge could also be important.
What are the symptoms of feline asthma?
Bronchial disease can affect any age of cat, and the most common symptoms include the following:
- Coughing-episodes of coughing can resemble vomiting or may be confused with the attempted expectoration of a hairball
- Loud breathing sounds or wheezing noises
- Rapid breathing and/or panting
- An “asthmatic attack” with acute respiratory distress and open mouth breathing – this situation can also be encountered in previously stable or medicated cats, and it requires immediate veterinary care.
What tests are needed?
The first and most important source of information is finding out as much as possible about your cat by talking with you, the owner. History can be helpful in identifying the cause of respiratory disease.
The most important diagnostic tool is a chest radiograph. Cats with asthma or bronchitis often have thickened airway wall, but they can also appear normal in some severely affected cats.
Depending on the findings of a physical exam and the radiographs, sometimes additional tests are required to determine the cause of respiratory problems, to assess the severity of disease, and to decide on specific therapy.
These diagnostic tests may include the following:
- Basic blood tests, to evaluate general health.
- More specific blood tests can rule out primary infections that could trigger airway inflammation and to rule out other conditions that might mimic asthma.
- In some areas of the country, heartworm disease must be investigated through use of blood tests or echocardiograph.
- Although extremely rare in this part of the world, lungworm infection in cats can also mimic asthma. To identify this condition a specific stool test on fresh, unrefrigerated feces must be performed.
- Collection of fluid from within the airways with a tracheal wash may also be useful. Your veterinarian may elect to anesthetize your cat briefly, place a tube into the airways, and inject a small volume of fluid into the lungs to “wash” cells from the airways. This fluid can be evaluated for the presence of bacteria or parasites that might trigger airway inflammation. The type of cells present in the lung can also be assessed.
What is the Treatment?
When infectious or parasitic causes of cough have been ruled out, and a primary inflammatory condition is considered most likely, treatment with steroids (prednisone or prednisolone) is generally employed for treatment of asthma or bronchitis. Oral medications are well tolerated by most cats. A high dose of steroids is used early in disease, and the dosage is gradually decreased as the cough resolves. It is important to keep in contact with your veterinarian regarding your cat’s response to medication because every animal requires a different type or amount of drug. Some cats can be tapered off of the medication, but many require some amount of steroid daily or every other day for the rest of their life.
In cats that suffer severe “asthma attacks” or in cats that don’t respond fully to steroids, a bronchodilator such as theophylline may be required to control signs. This drug often must be obtained from a human pharmacy. Sustained-release theophylline is usually given once daily in the evening. In some cats, vomiting, diarrhea, loss of appetite, or hyperexcitability can occur with use of this drug, but these are generally controlled with lowering of the dosage.
These drugs can be required life-long or may be given for only a short period of time. Be sure to consult with your veterinarian before discontinuing any medication.
Use of inhaled medications can be extremely helpful in controlling asthma. This is often chosen as a mode of therapy in cats that cannot be medicated orally or when systemic use of steroids should be avoided such as in cats with Diabetes. Metered-dose inhalers (MDIs) used in human medicine can be used in cats when a special dispensing (spacer) chamber is employed–Aerokat® www.aerokat.com. MDIs contain medication and propellant within a small steel canister and plastic shield. The MDI must be well shaken prior to use. Pressing onto the top of the MDI actuates the propellant, resulting in release of a fast-moving spray of medication. To transmit the medication into the lungs of the cat, the MDI must be actuated into a feline specific spacer—Aerokat®. With the facemask enclosing the lips and nose of the cat, one puff of drug is administered, and the cat inhales 8 to 10 breaths to pull the medicine into the lungs. IF your cat seems to react adversely to the sound of the actuation then you can do it first followed immediately by placing the mask on your cat’s face. Steroids and bronchodilators can be administered through this route. Medication may be required 1 to 4 times per day, and in cats with severe clinical signs, use of oral medication may also be required for the first several weeks of treatment. Although this method is more expensive than oral treatment, it can provide excellent control of symptoms. Inhaled Albuterol is the most effective medication to treat asthma attacks.