Restrictive Lung Diseases: Categories and Examples
Restrictive lung diseases are divided into two major categories: intrapulmonary (parenchymal) diseases and extrapulmonary (compression or chest wall) diseases 1, 2.
Intrapulmonary (Parenchymal) Restrictive Diseases
These involve direct lung tissue pathology with fibrotic reactions:
- Idiopathic Pulmonary Fibrosis (IPF) - the most extensively studied restrictive disease, characterized by usual interstitial pneumonia (UIP) pattern with progressive fibrosis 3, 4, 1
- Nonspecific Interstitial Pneumonia (NSIP) - typically presents with BAL lymphocytosis and more cellular lung biopsy patterns 3
- Hypersensitivity pneumonitis (chronic form) - often in the differential diagnosis of fibrotic lung disease 4
- Sarcoidosis (fibrotic stage) - can progress to restrictive physiology 3
- Systemic sclerosis-associated lung disease - particularly severe in black males with early disease and cardiac involvement, with FVC declining by 32% per year in the first 2 years 5
- Asbestosis - occupational exposure-related fibrosis 3
- Drug-induced lung disease - various medications can cause restrictive patterns 3, 4
- Eosinophilic pneumonia 3
Extrapulmonary Restrictive Diseases
These affect lung expansion without primary parenchymal involvement:
- Congestive heart failure - compression from cardiac enlargement and pulmonary edema 1, 2
- Obesity and obesity hypoventilation syndrome - increasingly common, often presenting with snoring, daytime somnolence, witnessed apneas, and morning headaches 1
- Neuromuscular disorders - including conditions causing respiratory muscle weakness requiring home non-invasive ventilation 1, 6
- Rib cage deformity - structural chest wall abnormalities limiting expansion 1, 7
- Diabetes mellitus - can cause restrictive patterns through various mechanisms 2
Key Diagnostic Distinction
A practical differentiating feature: intrapulmonary diseases typically show higher expiratory flows (PEF and MEF75/50/25) compared to extrapulmonary diseases because the conducting airways remain tethered in stiffened structures and resist compression during forceful expiration 2. However, this distinction has limited clinical utility with a peakflow cut-off of 65.8% showing only 30.1% positive predictive value for extrapulmonary disease 2.