By Dr. Irvin Mayers, MD
Approximately 8% of Canadian adults have clinically significant chronic obstructive pulmonary disease (COPD). The most common cause of COPD in Canadians is long-term cigarette smoking. There are other less common causes and one of these is a deficiency of a normal blood protein that protects the lung against permanent injury from smoke and other infections. This protein deficiency known as alpha-1 antitrypsin deficiency can result in severe COPD occurring at a younger age than is typical for COPD. There are estimated to be about 6,000 people in Canada with alpha-1 antitrypsin deficiency but the majority of people remain undiagnosed.
Diagnosis of alpha-1 antitrypsin deficiency can be made by a simple blood test or by genetic analysis. It should be very strongly considered in:
1. COPD in young adults (before the age of 45 y)
2. COPD without typical risk factors, such as cigarette smoking or work exposure.
3. Family history of COPD or emphysema at a young age.
This disorder should be considered in anyone already diagnosed with COPD or with severe, difficult to treat asthma. Treatment for COPD due to alpha-1 antitrypsin deficiency is similar to the usual treatment for COPD. Inhalers to improve lung function along with influenza immunization are standard treatments. In addition, it is imperative that patients stop smoking. The difference in life span for smokers compared with those who quit can be more than 10 years. There is an option for alpha-1 antitrypsin replacement therapy. This is given as an intravenous treatment every one to weeks and is continued indefinitely. In the setting where the patient has quit smoking this treatment can prevent the further loss of lung function. It is important to start this form of treatment early in the disease since once lung function is lost it cannot be recovered.