A patient with chronic cough and low serum α1-antitrypsin is likely to have which condition related to lung function?

The presence of low serum α1-antitrypsin levels in a patient with a chronic cough is strongly indicative of emphysema, particularly when considering the pathophysiology of alpha-1 antitrypsin deficiency. Alpha-1 antitrypsin is a protein that protects the lungs from damage caused by enzymes released by white blood cells during inflammation. In deficiency states, the lack of adequate levels of this protein leads to unopposed action of enzymes such as neutrophil elastase that can damage elastic fibers in the lung tissue.

This damage primarily affects the alveoli, leading to their destruction and resulting in the classic features of emphysema, such as difficulty in expiration and reduced lung compliance. The chronic cough seen in this patient could be secondary to chronic irritation of the airways or due to hyperreactivity related to the changes in lung structure.

While chronic bronchitis and COPD are also possibilities in patients with chronic cough, emphysema is specifically linked to α1-antitrypsin deficiency due to the mechanism of tissue destruction it incites. Asthma, on the other hand, is characterized by a reversible airway obstruction and does not relate to α1-antitrypsin levels. Thus, in the