Asthma and COPD- similarities and differences #14

   Until as recently as the 1960's Asthma and COPD were considered manifesations of the same disease. This was postulated because at that time, there were not many lung functions tests aside from spirometry and thus similar findings were atrtibuted to the same disease.
   A lot has happended since then. we now know these are two completely diffreent diseases with different pathologies and causes. A few differences include:

• Asthma symptoms are episodic whereas COPD symptoms vary very little
• Asthma usually begins in childhood wwhereas COPD usually occurs after the age of 40
• Initial epidoses of asthma are dramatic and occur quickly whereas COPD progresses slowly and often unnoticed
• ASthma generally responds well to the use of corticosteroids wehreas COPD does not respond as well
• Finally, the prognosis oin asthma is good with usually little or no progress whereas COPD is chronically progressive

   There is little doubt that both conditions are environmentally linked- Asthma through allergy and COPD mostly through tobacco smoke. Asthma's genetic link, though questionable in some circles, there seems to be a link through genes for the receptors or mediators of allergy (atopy). On the other hand, in COPD there is a definite genetic association  in one particular gene that is linked to alpha-1-antiproteinase deficiency,  a rather rare form of COPD that does show a hereditary path.

   In both asthma and COPD there does exist an inflammatory process in the lungs. this is where the similarity stops. In asthma eosinophils are usually increased and can be seen in routine blood these. Other cells present in asthma include IgE. The interaction of IgE and the allergen (i.e. animal dander,etc) causes mast cells and basophils to release histamine and other chemicals which lead to bronchoconstriction. In COPD the characteristic cellular culprits are macrophages, neutrophils and other chemicals which differ from those seen in asthma.

   One telltale difference is the reversibility of asthma as compared to COPD. In asthma, after treatment, the individual usually reverts back to normal lung function as show in a Peak Flow Meter test. On the other hand, COPD patients do not revert back to normal but continue their progressive decrease in lung function.