unknown lung disorder

my father has visited multiple hospitals and has been told he has a lung disorder. they have conducted various tests and still haven't decided what it is. i don't know much about medicine myself but any help would be much appreciated

[David S. Wilson, MD, FCCP]

Well...that is wide open but lung disorders fall into several large categories.  1. Airways diseases such as COPD, asthma 2. Interstitial lung diseases...there are many..the most common is Pulmonary Fibrosis. 3.Pulmonary blood vessels disorders such as blood clots and elevated blood pressure in the lung circulation.  4. infections such as bronchitis and pneumonia...the most common lung disorder in the US is COPD affecting over 22 million