The<unk> s <unk>  are a broad range of<unk>  lung diseases of unknown etiology characterized by expansion of the<unk>  compartment initially by inflammatory cells ending by fibrosis due to fibroblasts proliferation and subsequent collagen deposition. It generally manifests non specifically as breathlessness and cough and characterized by bilateral abnormal opacities of various types on conventional chest radiographs or computed tomographic (CT) scans. The prognosis of<unk>  differs according to the clinical course and pattern of the disease. The most common is chronic<unk>  pulmonary fibrosis (IPF), however the worst prognosis is the acute<unk>  pneumonia (AIP). The diagnosis can only be reached correctly with multidisciplinary approach among different specialists after excluding a lot of known factors that could cause the same presentations. Unfortunately most of the available treatments till today did not show any survival benefit or reducing the mortality.
Idiopathic interstitial pneumonia
CMV pneumonitis
Tuberculosis
Eosinophilic pneumonia
Diffuse panbronchiolitis
Atypical pneumonia
Bronchocentric granulomatosis
Hypersensitivity pneumonitis