Chronic bronchitis, gross specimen. Chronic bronchitis is one of a number of conditions referred to as a chronic obstructive pulmonary disease (COPD). It causes the network of airways in the lungs to become inflamed and produce mucus, and for the walls of the airways to thicken (as can be seen here). This can cause difficulty breathing and a productive cough. Other symptoms include fever and chest pain. Chronic (long-term) bronchitis is not necessarily caused by an infection and is most often seen in smokers. In this case smoking is a likely cause (the dark spots seen here are indicative of smoking).