Tracheobronchitis is a sudden or longterm inflammation of the trachea and bronchial airways; it may also extend into the lungs. It often occurs in dogs already affected by respiratory disease or a disorder of the lungs or airways. For example, infectious tracheo-bronchitis (kennel cough; see below) often follows a viral infection of the respiratory system. Other causes of tracheobronchitis in dogs include parasites, diseases of the mouth and pharynx, chronic coughing related to heart or lung disease, smoke inhalation, and exposure to chemical fumes.
Chronic bronchitis in middle-aged and older dogs may become worse following sudden changes in the weather or other environmental stresses. Animals with foreign bodies in the airway or developmental abnormalities such as deformities of the larynx may tend to develop bronchitis. Chronic bronchitis most often affects small breeds of dogs, although it is also seen in large breeds. Chronic bronchitis involves a cough that persists for at least 2 months that is not due to any other respiratory disease.
Spasms of coughing are the most prominent sign. The act of coughing is an attempt to remove accumulations of mucus and secretions from the respiratory passages; it is most severe after rest or a change of environment or at the beginning of exercise. The dog’s temperature may be slightly increased. The acute stage of bronchitis passes in 2 to 3 days; the cough, however, may persist for several weeks. Severe bronchitis and pneumonia are difficult to tell apart; in fact, bronchitis often extends from the bronchial tubes into the lung cells and results in pneumonia.
The veterinarian’s diagnosis is made from the history, physical examination, clinical signs and by ruling out other causes of coughing. Diagnostic tools include chest x-rays, use of an endoscope to view the bronchial tubes (bronchoscopy), and collection of biopsy and swab samples for laboratory analysis. Bronchial washing is an additional diagnostic aid that may demonstrate the agent causing the illness (for example, a parasite) or the animal’s response to disease (for example, the production of certain types of red blood cells). These diagnostic tests may be needed in cases where the veterinarian’s initial treatment is not effective in providing relief.
In mild cases or those with a recent onset of signs, supportive therapy may be effective, but treatment of the underlying disease (if present) is also needed. Rest, warmth, and proper hygiene are important. Corticosteroids are often used to decrease airway inflammation in dogs with chronic bronchitis. If bacterial infection is present, antibiotics may be prescribed. A persistent, dry (nonproductive) cough may be controlled by a prescribed cough suppressant that contains codeine. The veterinarian may perform or prescribe therapy such as use of a mist (nebulization) or steam from a hot shower to help loosen secretions and stimulate coughing up of secretions.
Infectious Tracheobronchitis of Dogs (Kennel Cough)
Infectious tracheobronchitis results from inflammation of the upper airways. It is a mild disease that normally improves on its own. However, it can progress to fatal bronchopneumonia in puppies or to chronic bronchitis in weakened, ill, or aged dogs. The disease spreads rapidly among susceptible dogs housed in close confinement, such as veterinary hospitals or kennels.
A number of viral and bacterial organisms can cause kennel cough. It is common to have infections with more than one of these organisms at the same time. Stress and environmental changes such as extremes of ventilation, temperature, and humidity appear to increase the dog’s susceptibility to disease as well as its severity.
The most common sign is spasms of harsh, dry coughing, which may be followed by retching and gagging. The severity of the cough usually diminishes during the first 5 days, but the disease persists for 10 to 20 days. Affected dogs have few if any additional signs except for some loss of appetite. Body temperature and white blood cell counts usually remain normal. Development of more severe signs, including fever, pus-containing nasal discharge, depression, loss of appetite, and a productive cough, especially in puppies, usually indicates the presence of an additional infection such as distemper or bronchopneumonia. Stress, particularly from adverse environmental conditions and improper nutrition, may contribute to a relapse during recovery.
Tracheobronchitis is usually suspected whenever a dog demonstrates the distinctive harsh cough and has a history of exposure to other susceptible or affected dogs. Laboratory tests are usually normal. Chest x-rays are important to determine the severity of the disease and to rule out other causes of coughing.
In most cases, affected dogs should not be hospitalized because the disease is highly contagious and because it generally improves on its own. The dog’s recovery may be hastened by good nutrition and hygiene, and (if needed) improvement of the animal’s living environment as recommended by the veterinarian. Cough suppressants are sometimes prescribed to control persistent nonproductive coughing. Antibiotics are usually not needed except in severe chronic cases. Cortico-steroids may be prescribed to help alleviate signs in dogs that are not severely ill. Aerosolization treatments ("breathing treatments") that contain antibiotics may also be helpful.
Vaccines are available to protect against distemper, parainfluenza, canine adenovirus-2, and Bordetella bronchiseptica, some of the main organisms responsible for kennel cough. Your veterinarian will recommend the types of vaccination, and vaccination schedule, most appropriate for your dog.