First, we need to confirm the diagnosis that it really is chronic bronchitis, and not due to other things, i.e. infection/TB/tumours.
Then we need to find the cause. Sometimes the cause might be obvious, i.e. smoking. Sometimes, the cause is not so obvious and might require further testing by a lung specialist.
Then we try to treat the underlying cause. For example: if it is due to smoking, to quit smoking.
And some patient might require inhaler medications or other oral medications.
