Lung worm

sir r their any vets that can tell me the symptoms of lung worm i have a staff called tesswho coughts a lot and kecks a lot .have taken here 2 the local vets who gave me a tablet called predisolone 5mg but had 2 go back and the vet gave my staff chest xrays showing some white patches on her lungs and liver enlargement .andthese other tablets corvental-d blue and grey 100mg andcorvental D 200mg at mo i take her out walking and she only kecks once or twice .but when she is in the house she kecks all the time why is that?would it b dry atmosphere in doors or some thing else thank you ralph