Bronchial Asthma in Cats
Overview of Feline Asthma
Asthma is a lung condition associated with airway obstruction caused by sudden narrowing of the bronchial tubes. In cats, asthma may also be known as “Feline Allergic Asthma”, “Feline Allergic Bronchitis”, “Feline Lower Airway Disease” or Feline Eosinophilic Bronchitis”.
Below is an overview of feline asthma followed by in-depth information about the diagnosis, treatment and prognosis for this condition.
Typical symptoms include difficulty breathing (dyspnea), coughing and/or wheezing. These symptoms are caused by the spasmodic constriction of the bronchial tubes and increased production of secretions from the bronchial tree.
The cause of asthma in cats is not yet completely understood. Some type of hypersensitivity response is generally blamed; however, an inciting cause is often not identified. The symptoms can range from infrequent to recurrent to constant. In some cats the disease appears to be seasonal, while in others there is recurring and eventually relentless progression of respiratory signs. Some cats may be asymptomatic between bouts of acute airway obstruction, whereas severely affected cats may have a persistent daily cough.
In some cats the symptoms begin to resemble chronic bronchitis as might be seen with a human smoker’s cough. Asthma can be very serious and some cats die from respiratory failure unless they are given prompt treatment. Even with treatment, the disease can progress.
Cats of all ages can be affected. The Siamese breed and obese cats may have an increased incidence of disease. Affected cats are often young to middle-aged at time of diagnosis.
Asthma may be triggered by stress or by some change in the environment such as move to new house or opening of an attic or basement, a new brand of kitty litter or a new smoker in the house.
What to Watch For
Some cats may have an acute onset of signs while other cats may have signs that come and go. Other cats will have persistent chronic signs. Symptoms may include:
- Difficulty breathing
- Rapid breathing (tachypnea)
- Noisy breathing (such as wheezing)
- Abnormal posture – your cat may sit with head extended and elbows back
- Lethargy or fatigue
- Weight loss
- Poor condition
Diagnosis of Bronchial Asthma in Cats
Diagnostic tests are necessary to recognize feline bronchial asthma, and help exclude other diseases that may cause similar signs.
There is no single test that is diagnostic of feline bronchial asthma. The diagnosis is based on the history of labored breathing that is responsive to oxygen, corticosteroids (hormones), and or bronchodilators (which are agents that expand the air passages of the lungs), typical X-ray findings, and evidence of airway inflammation based on fluid analysis. It is important to rule out other causes of difficult respiration in your cat, such as heart failure, pneumonia, pleural effusion, tumors or chest injury, as the treatments for each condition are very different. It is also possible to have two concurrent diseases. Recommended tests may include:
- Complete medical history and physical examination
- Chest radiograph (X-ray)
- A heartworm test to rule out heartworm disease
- Fecal floatation test to check for parasites or lung flukes
- Feline leukemia and feline “AIDS” testing
- Blood tests such as biochemistry analysis and a complete blood count (CBC)
Treatment of Bronchial Asthma in Cats
- Initial therapy may require hospitalization with treatments that include corticosteroids, a bronchodilator drug such as aminophylline or terbutaline and oxygen.
- It is most beneficial to maintain a stress-free environment.
- Chronic therapy often involves therapy with steroids, such as prednisone or periodic injectable medications, and/or bronchodilator drugs. Steroid therapy can lead to side effects.
Home Care and Prevention
At home, administer all prescribed medications, follow your veterinarian’s directions and restrict caloric intake in overweight or obese cats. You should discuss proper diet with your veterinarian.
Prevention takes the form of minimizing the symptoms of asthma by removing irritants from the environment. Try to eliminate dusts and powders (such as flea powders or carpet cleaners). Consider changing litter types – change to sand, newspaper types, or low “dust” varieties – and clean furnace filters often. Try to eliminate smoking in the house (even on a trial basis) and consider using air cleaners/purifiers. Minimize use of aerosol sprays such as hairsprays and deodorizers.
In-depth Information on Feline Asthma
Asthma is a reactive airway disease, meaning the muscle lining the bronchial tubes can suddenly constrict leading to airway obstruction. Affected cats cannot expel air from their lungs and symptoms come on very suddenly.
Some cats have less obvious signs of reactive airways but prominent signs of bronchitis, meaning the bronchial tubes are inflamed and secretions accumulate and obstruct airways. In either case, breathing is difficult, coughing may occur and the lungs cannot function properly.
Bronchial asthma in cats is uncomfortable, tiring and the condition can be life-threatening.
Other medical problems can cause similar symptoms such as difficult breathing and coughing in cats. It is important to exclude these before establishing a diagnosis of feline bronchial asthma. These conditions include:
- Acute upper respiratory infections Feline. Symptoms are often related to the nasal cavity and eyes and include sneezing.
- Feline heartworm disease. Sudden, spontaneous death of a heartworm can lead to respiratory distress but chronic heartworm disease is more likely to cause coughing and vomiting.
- Lungworms infection. This is an important cause of chronic coughing in some geographic areas.
- Nasopharyngeal polyp. This inflammatory growth can obstruct the airways in the throat.
- Laryngeal disease. Although relatively uncommon in cats, it can cause breathing problems.
- Pleural effusion. An accumulation of fluid in the chest cavity causes respiratory difficulty and rapid breathing.
- Pneumonia (lung infections)
- Pulmonary edema (fluid in the lungs) is often due to heart failure in cats.
- Airway obstruction (foreign body, tumor) should be especially considered in cats that do not respond appropriately to therapy for asthma.
- Trauma or injury to the trachea (windpipe) or chest cavity
- Tumors or cancers of the lungs
Diagnostic tests are necessary to recognize feline bronchial asthma and exclude other diseases. Tests may include:
- Complete medical history and physical examination
- Chest X-rays. Although they can be normal, there are often changes typical of asthma or bronchial inflammation.
- A heartworm ELISA or antibody test to exclude heartworm disease.
- In some locations, a special fecal floatation to diagnose parasites or lung flukes. Multiple tests may be performed as parasites are intermittently shed and can be difficult to diagnose.
- A complete blood count (CBC). Some cats may have elevated eosinophils which is often seen with allergic or parasitic disease.
- Serum chemistries to rule out concurrent diseases, especially in sick cats.
- Test for the feline leukemia (FeLV) and FIV (feline AIDS virus) to check status of cats with chronic illnesses or those who may receive corticosteroids.
- A sample of fluid from the lungs (tracheal-bronchial washings or airway lavage) to diagnose lung problems. The fluid collected is examined microscopically (cytology) and cultured for infectious diseases. Some cats with asthma/bronchitis also can develop a lung infection.
- Additional diagnostic tests may be recommended on an individual pet basis, including:
- Bronchoscopy. In this procedure, a small flexible fiber optic tube is inserted into your cat’s airway (tracheobronchial tree) to allow examination for foreign bodies, laryngeal abnormalities, nasopharyngeal polyps, parasites and tumors. Fluid from the lung can be collected and analyzed.
- Echocardiography (heart ultrasound exam) may be indicated if heart disease and heart failure cannot be excluded as a diagnosis. Echo is also helpful in diagnosing feline heartworm disease because the worms can be seen by ultrasound.
Many cats with asthma are too sick to undergo such testing and need to be treated medically first, based on examination or examination and chest X-rays. Treatments for feline asthma vary. If your cat has only mild clinical signs, no treatment may be recommended. In this case, a regular follow-up is important to follow progression of disease. In the case of acute respiratory distress, hospitalization is needed initially. Drugs may be administered orally, by injection or by metered dose inhaler (MDI) depending on the needs of the patient.
Recommendations for an acute asthma attack may include:
- Minimal handling if distressed. The patient should be stabilized first before instituting diagnostics such as the chest radiograph or laboratory work. Treatment is essentially aimed toward treating the symptoms until the patient can be stabilized.
- Oxygen cage or cool well-ventilated, quiet area.
- Bronchodilators may be used to relax the airway smooth muscle contraction. Aminophylline, theophylline (Theo-Dur), albuterol, or terbutaline may be most effective drugs since they work faster than steroids. Bronchodilator therapy is often used orally for chronic therapy and by inhaler (MDI) for “rescue” therapy.
- Steroids such as dexamethasone sodium phosphate (Azium SP®) or prednisone sodium succinate to reduce inflammation in the acute phase.
- Steroid therapy is the most effective long-term treatment for asthma. Oral prednisone or prednisolone is recommended when there is no evidence of pneumonia. In some cats, long acting injectable corticosteroids work better; however, there is also greater risk of side effects.
- Epinephrine (Adrenaline) may be given if airway obstruction is life threatening or if there is a poor response to above treatments.
- Antibiotics may be indicated if there is evidence of an infectious component. Antibiotics are not routinely indicated in asthma, however, and do not relieve asthma symptoms.
- Panacur deworming is recommended in cats that might be exposed to lungworms. Routine deworming is recommended on a regular basis.
- Cyproheptadine (Periactin®) is an antihistamine that shown positive effects in some asthmatic cats. Indications include cats that are unresponsive to maximal doses of steroids and bronchodilators. Cyproheptadine comes in pill and liquid forms.
- Cyclosporine is used in some cats that are unresponsive to traditional treatments. If used, drug blood monitoring is recommended.
- Anti-Interleukin-5 is an experimental treatment for asthma that is not yet available.
- Heavy sedation, intubation and ventilation are required in cats suffering from impending respiratory arrest.
- Cyproheptadine is used in some cats to help alleviate airway hypersensitivity. It can work in a small percentage of cats.
Prognosis for Feline Asthma
The prognosis for cats with feline asthma is dependent on the severity of the disease. Mildly affected cats have a very good prognosis and live a normal life with minimal intervention. Cats with severe disease may have frequent attacks that require periodic hospitalization and injectable or inhalation therapy at home. In severe cases, airway inflammation can damage the lungs causing a poor prognosis.
Optimal treatment for your pet with feline asthma requires a combination of home care and professional veterinary care. The duration of therapy needed is variable, because some cats may have only a single event while others require lifelong therapy or recurrent treatments (not unlike people with asthma). The principles of home care therapy for bronchial asthma in cats include the following:
- Administer veterinarian prescribed medication and be certain to alert your veterinarian if you are experiencing problems treating your pet.
- Injectable terbutaline – In the case of severe episodes of respiratory distress, some veterinarians advocate the use of this drug at home. This may be an option to discuss with your veterinarian.
- Attempt to taper the doses of corticosteroids under your veterinarian’s directions. Corticosteroid therapy in cats is often well tolerated, but chronic use can lead to weight gain, obesity and diabetes.
- Re-evaluate your cat if there is an inadequate response to the above. Schedule a recheck for one to two weeks after an acute attack.
- Periodic chest X-rays every 6 to 12 months can help follow progression of disease. Understand the relentless nature of this condition in some cats.
- Restrict calories in obese pets. Obesity worsens lung function.
- Try to minimize or eliminate dusts and powders from the environment. Change litter types to sand, newspaper types, or low “dust” varieties. Clean furnace filters and consider air cleaners/purifiers to reduce environmental pollutants.
- Try to eliminate smoking in the house (even on a trial basis). Minimize exposure of cats to aerosol sprays such those found in as hairspray or deodorizers.
- Use Hepa-type air filters to help filter air.
- Keep a calendar of when asthmatic attack or problems occur to help determine any seasonality that can be associated with specific allergens.