Interstitial Lung Disease

a) To those who struggle with memorization such as myself, frameworks can be helpful. ILD can be sub-classified as secondary to: exposures (e.g. pneumoconioses), systemic disease (e.g. collagen vascular disease, sarcoid, CHF, tumor), drugs (e.g. amiodarone, bleomycin), and idiopathic interstitial pneumonias.

b) Idiopathic interstitial pneumonias (COP, AIP, NSIP, LIP, DSIP, RBIP) are primarily histopathologic diagnoses which require a lung biopsy. The exception is idiopathic pulmonary fibrosis, which correlates with usual interstitial pneumonia on path. It is worth remembering this as it is the only subtype where the dx can be made radiographically.

c) In addition to HRCT, further diagnostic studies include PFTs (which typically show a restrictive defect and reduced DLCO), BAL (to evaluate cellularity and for infection), and video assisted thoracoscopic surgery (VATS) to obtain tissue. Transbronchial biopsy via bronch is typically of low yield.

(Christopher Woo MD, 6/8/10)