Overview of Canine Pulmonary Fibrosis
Pulmonary fibrosis (PF) is the presence of increased fibrous (scar) tissue in the lungs as a consequence of lung tissue injury. The exact cause in most cases is unknown; however, underlying progressive inflammation of the alveoli (alveolitis), injury or recurrent congestion of the lung (as with heart failure) seem to predispose dogs to PF.
Hundreds of inhaled, ingested and administered chemicals, dusts, gases, pollutants and drugs are capable of inducing lung fibrosis in humans. Presumably, dogs react in a similar manner. Inorganic and organic dusts, gases and vapors, drugs and infectious agents have been implicated, but pinpointing an exact cause is difficult.
Fibrosis of the lungs makes the lungs stiffer and prevents normal expansion. There is usually impaired movement of oxygen across the lungs and low oxygen content in the blood. These problems lead to tiring and shortness of breath.
It is quite likely that severe, diffuse lung fibrosis in middle-aged and older dogs is preceded by alveolitis similar to that associated with chronic pulmonary fibrosis in humans.
The typical dog with pulmonary fibrosis is an older small or medium sized breed. Many dogs are concurrently overweight. Some are also be affected by bronchitis (inflammation of the bronchial tree, similar to a smoker’s cough). Small terrier breeds, especially West Highland white terriers are predisposed to this problem.
What to Watch For
Signs of pulmonary fibrosis in dogs may include:
Coughing is remarkably absent unless there is concurrent bronchitis.
Diagnosis of Pulmonary Fibrosis in Dogs
Diagnostic tests are needed to recognize PF and exclude other diseases, including:
Treatment of Pulmonary Fibrosis in Dogs
PF is often a severe and progressive condition that causes difficulty breathing. Therapy of pulmonary fibrosis is frustrating because the underlying cause of lung inflammation or scar tissue is rarely determined or controlled. Therapy does not reverse fibrosis, though it may prevent future inflammation or lung injury. Treatments for PF may include:
Home Care and Prevention
Weight loss in overweight dogs can reduce the work of breathing, so stick to a diet for your pet that has been prescribed by your veterinarian. Reduce your pet’s exposure to dust, chemicals and smoke.
Exercise limitations should be imposed if your dog becomes short of breath. Provide only exercise that your pet can tolerate. Use a harness on your pet instead of a neck collar.
Follow up with your veterinarian as needed for examination, laboratory tests and chest X-rays.
There are not any specific recommendations for prevention of PF. Obesity should be controlled and eliminate exposure to smoke, dusts, fumes, barns and crop dust.
In-depth Information on Pulmonary Fibrosis in Dogs
Other medical problems can lead to symptoms similar to those encountered in pulmonary fibrosis (PF). Radiographs and bronchoalveolar lavage [BAL] will often diagnose pulmonary fibrosis.
Further diagnostic testing may be needed to determine secondary factors such as active inflammation or to eliminate other causes of similar symptoms like heart disease. Diseases that can appear similar to those with (PF) include: