Canine chronic bronchitis in dogs is defined as coughing on most days of at least 2 months duration, with no underlying cause such as pneumonia. It is believed that it is the result of a long-standing inflammatory process that is initiated by infection, allergy, or inhaled irritants or toxins. The inflammation can cause irreversible changes to the lungs so it is important to diagnose and treat these patients to try to prevent these changes. Certain breeds of dogs are prone to more severe forms of this disease and should be diagnosed and treated to slow down progression of the disease.
Chronic bronchitis is diagnosed by a combination of physical examination, imaging, and laboratory tests. Chest x-rays may show a characteristic pattern, and are also a non-invasive way to monitor response to treatment or progression. Further tests such as bronchoscopy are used to confirm the diagnosis, and to eliminate other potential causes of cough such as infection, tumors, foreign material, or anatomical abnormalities. Bronchoscopy is a procedure where a sterile tube with a camera at the end and a port for obtaining samples is placed in the petís airway to look at the trachea and bronchioles and collect samples for analysis and culture. It involves a brief general anesthesia. A tracheal wash can also be used to obtain samples, however, this procedure does not allow visualization of the airway for tumors, foreign material or anatomical abnormalities.
Treatment of chronic bronchitis typically involves drugs to open the airways, and to decrease inflammation. Exacerbating factors such as environmental triggers (ie smoke) and infections should also be addressed. Dogs with more severe cases of chronic bronchitis may develop secondary problems such as airway collapse and pulmonary hypertension that may require treatment.