Restrictive Lung Disease
March 4th, 2023
Overview
While spirometric values such as FEV₁ and FVC can be suggestive of restrictive lung disease, a reduced total lung capacity (TLC) of 80% predicted is diagnostic.
Pulmonary Function Test Findings
- FEV₁ reduced (<80% predicted)
- FVC reduced (<80% predicted)
- FEV₁:FVC ratio normal (>0.7)
- Reduced volume in flow-volume loop
- TLC <80% predicted
- DLCO normal (extrapulmonary) or decreased (parenchymal)
Causes of Restrictive Disease
Parenchymal
- Pulmonary fibrosis
- Sarcoidosis
- Atelectasis
Extrapulmonary
- Pleural - pleural effusion, pneumothorax
- Chest wall deformity - kyphosis, scoliosis, morbid obesity
- Neurologic / neuromuscular / muscular disorder - motor neurone disease, Guillain-Barre, muscular dystrophy, myasthenia gravis
Severity of Restrictive Disease
Based on TLC:- Mild - 70-80% predicted
- Moderate - 60-70% predicted
- Moderately severe - 50-60% predicted
- Severe - <50% predicted
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------