Introduction: The respiratory tract or system is the collective set of parts and tissues which provides for the inhalation of air, the passage of oxygen into the bloodstream, the passage of waste gases out of the bloodstream, and the exhalation of those same waste gases into the environment. This section concentrates on abnormalities in the parts and tissues of the lungs, trachea, larynx, and mouth. Some problems may actually originate outside of the respiratory tract, but have a direct influence on these structures and the normal passage of air and exchange of oxygen.
Causative Agents: There are many reasons for an animal to have respiratory problems. The following list covers only a few of the most common:
- Parasites, including heartworm disease
- Fractured ribs
- Diaphragm injuries
- Scar tissue formation
- Air leakage into the chest space (pneumothorax)
3. Heart disease
4. Drugs or noxious substances
- Rodenticide poisons
- Smoke inhalation
- Aspiration pneumonia (inhaling vomit or food into the lungs)
- Drowning/Near drowning
7. Electric shock (i.e. chewing on electrical cords)
8. Congenital birth defects
- Brachycephalic airway syndrome
9. Degenerative diseases
- Collapsing trachea
10. Pulmonary thromboembolism (blood clots lodged in the lung vessels)
Clinical Signs: Depending on the cause of the respiratory problem, many different signs are possible. In general, coughing, difficulty breathing, or shortness of breath are universal clinical signs, and may occur with any of the above causes.
Diagnosis: A complete and thorough history is important for an accurate diagnosis. This requires that the owner be prepared to give specific information concerning the pet. Some essential pieces of information may include the following:
Once the history is taken, a physical exam is performed. A complete examination of the respiratory system includes listening to the lungs and trachea with a stethoscope, temperature measurement, and examination of the mouth/throat region, eyes, lymph nodes, and mucous membranes. Additional procedures that may be required include radiography (X-rays) of the upper body, evaluation of a fluid sample from the lungs (the sample is usually obtained by means of a test known as a transtracheal wash or aspiration), and/or examination of the airways using an endoscope. These procedures help the veterinarian to more specifically diagnose the problem. For additional information on the above procedures and tests, refer to Sections B and D.
Treatment: Depending on the particular cause of the present problem, a combination of many different treatments is available. Some general treatments/supportive care for patients with respiratory disease include antibiotics, anti-inflammatory medications, oxygen, cough suppressants, and IV fluids.
More specific treatment varies as widely as does the list of respiratory problems. Other therapeutic procedures include thoracocentesis (insertion of a needle or tube into the chest space to draw out fluid or air), tracheostomy (opening a hole into the trachea to help the animal breathe while an obstruction in the mouth or larynx is removed), chest percussion (gentle drumming on the chest wall with a cupped hand to help dislodge and move debris into the airways), humidification therapy (to help moisten lodged debris in the lungs and aid in oxygen transfer), and surgery.
Prevention: Many problems with respiratory infections can be avoided with routine vaccinations and de-worming. Careful attention to avoid exposure to diseased animals is also critical. A quick recognition and then proper treatment is the best approach. Quick recognition of a problem by the owner relies greatly on a basic knowledge of a petís normal behavior. For suggestions on normal respiratory rates and how to listen to the lungs, refer to pages A560 and B890. The information found on page A30 can be helpful in learning how to be an observant and alert pet owner. Vaccination and de-worming suggestions can be found on pages A905 and A622.