These two are different in that chronic bronchitis is defined by clinical features, like a productive cough, whereas emphysema is defined by structural changes —specifically enlargement of the air spaces.
It turns out that emphysema can develop in a couple different ways, and alpha-1 antitrypsin deficiency causes pan-acinar emphysema, meaning the whole acinus is affected, and it also tends to affect the lungs’ lower lobes the most.