Feline Bronchopulmonary Disease
The respiratory system functions to exchange oxygen and carbon dioxide during respiration (breathing). The respiratory tract consists of the upper (nose and nasal passages) and lower airways (trachea, bronchi and lungs). Within the lung, the bronchi divide into bronchioles and terminate in the alveoli where gas exchange actually takes place.
Feline Bronchopulmonary Disease (FBD) is a collective term to describe lower airway disease in cats. FBD can be caused by many irritants including allergens, chemicals, smoke, and inhalant particles (dust) although the exact cause is unknown. These irritants trigger inflammation of the bronchi and bronchioles which then causes excess mucous production and muscular constriction of the airways. The constriction prevents adequate movement of air within the lungs which is manifested by difficulty when breathing.
Cats may suffer from chronic airway inflammation (chronic bronchitis), which usually manifests as daily, frequent coughing. If left untreated, the chronic inflammation may lead to scarring of the bronchioles which decreases the lung’s ability to inflate with air. In other cases, airway constriction can be an acute event that occurs suddenly, without prior signs. Symptoms may include rapid, difficult breathing with effort or open mouth breathing. Often, this is referred to as an asthma attack and can be a medical emergency. In either of these cases, other symptoms may include decreased appetite, decreased playfulness, or lethargy. FBD can occur in cats of any age, but is most common in cats between the ages of 2–8 years.
In stable, non-emergent situations, your veterinarian will begin diagnosis with a thorough physical examination. Cats that are having difficulty breathing may require oxygen supplementation and rest and only a limited exam and treatment may be performed until the cat is more stable. X-rays (radiographs) of the chest are performed to examine the airways to look for characteristic changes associated with bronchiolar inflammation and to rule out other causes of respiratory distress like heart disease, pneumonia, trauma, or lung cancer. In some cases, radiographs may show minimal lung changes and further diagnostic tests to obtain cellular samples from the lung (transtracheal wash, bronchoscopy) may be recommended. Blood work and urinalysis are performed to determine whether infection is present and to help determine if the respiratory problem is acute or chronic. Occasionally, a fecal sample will be taken to rule out lung parasites.
In acute or chronic cases, the goal of therapy is to reduce inflammation within the airways and relieve bronchoconstriction.
Steroids block the production of inflammatory chemicals that are produced within the lungs. Steroids may be administered by injection (typically in emergency situations), orally, or by inhaler. With injectable or oral steroids, potential side effects may occur with long term use or high doses because the drug is administered systemically. Diabetes mellitus, immune suppression, renal insufficiency and rarely, heart failure are potential side effects that have been observed in cats. Therefore, it is important to taper the dose of steroid to the lowest dose possible that still alleviates symptoms to try to avoid the development of side effects. Your veterinarian will help you determine the best way to administer steroids to your cat. Frequent monitoring of cats on steroids is also recommended.
Terbutaline is a medication that reduces airway constriction rapidly. It can be used as an injection or as a twice daily oral medication. Albuterol is a bronchodilator that is administered via inhaler and can be used in emergency situations. Both medications are short-acting and side effects include increased heart rate and nervousness.
Minimizing potential airway irritants may help alleviate some symptoms in your cat.
- Avoid cigarette smoke, incense, or scented candles
- Minimize use of spray deodorizers or other aerosols
- Use low dust, unscented litters
- Replace home air filters frequently
- Consider using an air filter in an area where your cat spends a lot of time
****ACUTE ASTHMA ATTACKS CAN BE LIFE THREATENING****
If you see your cat open-mouth breathing or having difficult, rapid respiration this is an emergency- contact your veterinarian IMMEDIATELY!