ANSWERThere is a broad differential at this point.
includes in order of decreasing likelihood
(1) Inhalational disease
(2) Infectious causes including viral, bacterial including TB and atypical mycobacteria and fungal disease
(3) Sarcoidosis and other granulomatous disease
(4) Idiopathic interstitial disease
(5) Cystic fibrosis
(6) Drug reactions
Hypersensitivity pneumonitis is high on the list of differentials as the history of fluctuating symptoms is very characteristic. Infection especially TB must be out ruled in this situation. Sarcoidosis, other granulomatous diseases, neoplastic conditions, cystic fibrosis or vasculitis are less likely differentials.
Initial investigation included a CBC with the following result. White blood count 10.1x 109/L, Peripheral eosinophil count 870 (Normal 250-500) Hemoglobin 14.1 g/L Platelets 357X 109/L.
Pulmonary function tests were as follows:
ON THESE RESULTS, WHAT IS YOUR DIFFERENTIAL NOW?