Emphysema May Explain Worsening Lung Function in Nonsmokers with Asthma
Unsuspected emphysema was the culprit in worsening lung function in some adults with chronic asthma who had never smoked, according to a study published in CHEST in 2018.
Over a number of years, researchers tested 25 patients by giving them doses of inhaler medication and then measuring their breathing. The study focused on one of the 25, who needed a lung transplant. When researchers examined the removed lung, they found mild emphysema, reinforcing previous studies that showed emphysema in autopsied lungs of four people with chronic asthma.
The air sacs of people with emphysema, which is usually caused by smoking, become damaged. It becomes more difficult to breathe out, and carbon dioxide gets trapped in the lungs; also, new oxygen has trouble entering. Asthma, in contrast, is mainly characterized by swollen airways.
The reasons behind the loss of elasticity in the lungs of people with chronic asthma—present in all 25 study patients—have historically been something of a mystery, the researchers wrote. Yet certain experts have suspected for a long time that emphysema and asthma may not be completely distinct. At a 1961 symposium in the Netherlands, one group of researchers theorized that emphysema, bronchitis, and asthma should be considered different varieties of one basic disease form. The authors hope that their study will lead to additional research.