COPD is a disease characterized with permanent damage to the lungs. It is progressive and cannot be reversed. The current thinking is that the best way to prevent progression is to identify it early in its development. This can be quite difficult because frequently these individuals, usually middle-age smokers, don’t have obvious symptoms.
The theory is that these smokers are unique. They have an exaggerated decline of lung function, beyond the normal deterioration that is expected with age. There is, however, new evidence that COPD may already be present in adolescence. This raises new questions of how to identify these teens.
A recent study conducted at the University of Copenhagen revealed that the proportion of patients with COPD identified to have this accelerated decline of lung function is only 50 percent. The remaining individuals with COPD may already have developed the disease earlier in life. It is theorized that these non-smokers with early disease have a suboptimal development of their lungs during the younger years.
There are some cases in which this is easy to point out. For example, children from poor families who have a history of severe pneumonias and poorly treated tuberculosis. There are, however, some other young people in whom there is no obvious explanation. Frequently they are classified as poorly controlled asthmatics. Indeed, many physicians who are in primary care use the diagnosis of asthma and COPD concurrently, without clear objective criteria.
This brings up the discussion of the similarities and differences of COPD and Asthma. It is assumed that asthma is a disease with symptoms due to narrowing of the airways, caused by inflammation. However, once the inflammation is treated, usually with inhaled steroids, symptoms subside and the anatomy of the lungs remains normal.
This assumption is no longer accepted. There are many asthmatics who are poorly controlled and who do, over time, develop abnormalities similar to COPD.
To attempt to identify objective factors (to correctly classify the disease), the Global Initiative for COPD set up the world guidelines for treatment (known as the GOLD Guidelines) and coined the term** Asthma COPD Overlap Syndrome or ACOS**.
The Gold Guidelines stress the importance of history taking rather than simply relying on spirometric test results. It’s crucial to learn the factors in children that are responsible for such poor lung development. This may include frequent infections and severe pneumonias, but also environmental factors like exposure to indoor pollutants, fumes from wood stove heating, and most importantly, secondhand smoking.
The effect of secondhand smoke on children has been known for years, but it has mostly been linked with degree of severity of asthma in adulthood. Now the development of COPD is also attributed to secondhand smoke exposure.
There are many remaining difficulties in addressing this confusion between COPD and asthma. Patients who are smokers, and often develop COPD, cause the lung damage through other pathways, which differentiates them from the teens who may develop early COPD.
Why is this important? The treatments recommended will often depend on identifying the underlying activity that causes the damage in the lungs. Asthmatics frequently have an allergic component where the active cells of inflammation are eosiniphils. In COPD the cells that are responsible for destruction in the lungs are neutrophils, which have granules containing toxic substances.
Furthermore, infections in childhood are not necessarily all bad. In an earlier sharepost I discuss the Hygiene Hypothesis, which explains that some infections early in life actually create a protective effect against asthma in adulthood.
A better understanding of how (and when) this destructive disease COPD, develops, will allow for better understanding of potential causative factors including genetics, and modifiable factors that can be avoided.