Chronic Bronchitis in Cats

By Malcolm Weir, DVM, MSc, MPH; Cheryl Yuill, DVM, MSc, CVH

What is chronic bronchitis in cats?

Chronic bronchitis is a long-term inflammatory condition that affects the pulmonary or respiratory system. This condition is slowly progressive and irreversible.

What causes chronic bronchitis?

There are no definitive underlying causes of chronic bronchitis. However, long-term airway inflammation may result from exposure to inhaled irritants such as tobacco smoke, air pollutants or allergens. Dental disease, or  recurrent infections of the respiratory system may also be underlying causes of chronic bronchitis.

Are there other factors that can make chronic bronchitis worse?

Yes. Obesity is a complicating factor and will worsen symptoms. Dental disease also increases the risk because bacteria can travel from the mouth into the lungs and cause a serious secondary infection.

What part of the respiratory system is involved in chronic bronchitis?

The respiratory system is divided into two parts. The upper respiratory tract consists of the nose, nasal sinuses, throat and trachea or windpipe, while the lower respiratory tract consists of the "small airways" (bronchi and bronchioles) and the alveoli (the small air sacs deep in the lung tissue where oxygen exchange occurs). Chronic bronchitis is a condition of the lower respiratory tract. Initially it affects the small airways, although in advanced cases, it will progress and affect the alveoli.

How does chronic bronchitis affect a cat's lungs?

In its early stages, chronic bronchitis causes inflammation in the small airways. Persistent inflammation will cause blockage of the small airways and will ultimately result in reactive changes in the lungs, including dilation in parts of the small airways (bronchiectasis) or scarring in the lungs (pulmonary fibrosis).

How fast do these changes occur?

This condition develops slowly and progressively.

Does it affect all breeds and ages of cat?

Chronic bronchitis most often affects middle-aged and older cats. There is some evidence to suggest that Siamese cats may be at a higher risk of developing this condition.

What are the symptoms of chronic bronchitis?

In its early stages, the main symptom of chronic bronchitis is constant coughing, or coughing that persists for longer than a month. The cough is usually "dry" or harsh, and gagging is common after coughing (some owners mistakenly think their cat is vomiting when in fact it is coughing). As the disease progresses, the cat may appear to have less energy and may have difficulty breathing. Breathing may become noisy, and a cat may wheeze when exhaling. In later stages, the gums may develop a bluish tinge due to a lack of oxygen. Cats with chronic bronchitis rarely have a fever and usually their appetite remains normal.

Could these symptoms be caused by something else?

Chronic coughing may also be a symptom of a lung infection or some types of cancers. Coughing is a common symptom of heart disease in people and in dogs, but is not usually a symptom of heart disease in cats.

How is chronic bronchitis diagnosed?

Your veterinarian may suspect a diagnosis of chronic bronchitis based on your pet's history and the results of a physical examination. When the chest is listened to with a stethoscope, "crackles" (harsh crackling or popping sounds) may be heard when the cat breathes in and out. With chronic bronchitis, the heart rate is usually normal or lower than normal.

A thorough medical history documenting the onset of the problem and its progression, any changes in the cat's home environment, or any other signs of illness in the cat, will be important to help rule in or rule out other diseases. Diagnostic tests may include blood tests, radiography, a bronchoscopic examination, and/or a procedure called tracheal washing. Samples collected by a bronchoscopy or tracheal washing will be submitted for specific laboratory testing such as cytology (microscopic examination of cells), histology (microscopic examination of tissue samples) or bacterial identification and culture. A cat will usually require sedation or anesthesia for some of these procedures.

What is the treatment for chronic bronchitis?

Most cats with chronic bronchitis are treated as outpatients. If the cat is experiencing severe respiratory distress, hospitalization for oxygen therapy and/or intravenous medication to stabilize the condition may be required.

Specific medications that may be prescribed to treat chronic bronchitis include: bronchodilators to dilate the airways and help clear secretions, cough suppressants, antibiotics if there is evidence of a secondary bacterial infection, and/or corticosteroids to decrease the inflammation and ease the coughing. Avoidance of irritants such as smoke or airborne allergens will help lessen the chance of relapses.

Newer therapies for chronic bronchitis include stem cell therapy and desensitization with allergen-specific immunotherapy (“allergy shots”).

Non-specific treatments for chronic bronchitis may include diet modification to promote weight loss in an overweight cat. Your veterinarian may prescribe supplements that have antioxidant, anti-inflammatory or immune stimulant functions as supportive treatments.

It is important to maintain good oral health in a cat with chronic bronchitis. Daily toothbrushing is extremely beneficial. Regular dental descaling, cleaning and polishing under general anesthesia is strongly recommended to minimize the chance that bacteria from the mouth will cause a secondary infection in the inflamed respiratory tract.

What is the success rate for treatment of chronic bronchitis?

This condition is non-reversible and often slowly progressive. Appropriate treatment will slow the progression of the disease and will relieve distressing symptoms. With proper management, most cats with chronic bronchitis enjoy a normal life expectancy and an excellent quality of life. Relapses may occur when the seasons change or if air quality is poor.

Adjustments to medication dosages may be necessary at these times. Consult your veterinary clinic for specific advice.

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