Interstitial Lung Disease (restrictive) Cheat Sheet

Pathop­hys­iology

• Inflam­matory process involving the alveolar wall (resulting in widespread fibroe­lastic • prolif­eration and collagen deposition).
• Can lead to irreve­rsible fibrosis, distortion of the lung archit­ecture, and impaired gas exchange.
• Prognosis is very variable and depends on diagnosis.

Signs

• Rales at the bases are common, digital clubbing is common (esp. in idiopathic pulmonary fibrosis), signs of pulmonary HTN and cyanosis in advanced disease.

Diagnosis

• CXR, CT, PFTs, oxygen desatu­ration during exercise.
• Bronch­oal­veolar lavage for culture and cytology yields variable results.
• Tissue biopsy is often required and can be done via fiberoptic bronch­oscopy with transb­ron­chial biopsy (limited utility), open lung biopsy, or video-­ass­isted thorac­oscopic lung biopsy (VATS).
• UA can show signs of glomerular injury in Goodpa­stu­re's or Wegene­r's.

Enviro­nmental

• Coal worker­'s pneumo­con­iasis, silicosis, asbest­osis, beryll­iosis.

Alveolar Filling Disease

• Goodpa­stu­re's syndrome, Idiopathic pulmonary hemosi­der­osis, alveolar protei­nosis.

Drug Induced

• Amiodarone, nitrof­ura­ntoin, bleomycin, phenytoin, illicit drugs.

CXR

• Typical diffuse changes are noted (reticular, reticu­lon­odular, ground glass, honeyc­ombing).
• Honeyc­ombing refers to a scarred shrunken lung and is an end-stage finding with poor prognosis. Air spaces are dilated and there are fibrous scars in the inters­titial. Can arise from many causes of ILD.

CT Scan

• Shows the extent of fibrosis better than other imaging. Fibrosis, honeyc­ombing, or traction bronch­iec­tasis.