Idiopathic Interstitial Pneumonia/Interstitial Lung Disease (ILD)
Introduction
A rheumatologist, pulmonologist, hospitalist, or ICU provider is often confronted with diffuse lung disease. The functional part of the lung, the part that exchanges gases is called the parenchyma. When the parenchyma is infiltrated with disease such as inflammation, tumor, fluid or fibrosis (scarring) and this is widespread, it is referred to as diffuse parenchymal lung disease. According to Talmadge King in Uptodate, "Diffuse parenchymal lung diseases consist of disorders of known causes (rheumatic disease, environmental or drug related) as well as disorders of unknown cause. The latter include IIPs, granulomatous lung disorders (eg, sarcoidosis), and other forms of interstitial lung disease including LAM, PLCH, and eosinophilic pneumonia. The interstitial pneumonias are further categorized as chronic fibrosing, acute or subacute fibrosing, or smoking-related. Lymphoid interstitial pneumonia is typically associated with other disease processes, such as rheumatic disease or immunosuppression; idiopathic lymphoid interstitial pneumonia is rare." [1]
Let's Categorize
- DPLD unknown cause (drug related, rheumatologic)
- Idiopathic interstitial pneumonia (IIP)
- Granulomatous
- Other
IIP
The idiopathic interstitial pneumonias (IIPs) are a subset of diffuse interstitial lung diseases with unknown etiology. The IIPs are classified based on their histopathologic appearance as outlined in a joint American Thoracic Society and European Respiratory Society (ATS/ERS) [2]
- Chronic
- Acute
- Smoking related
Chronic IIP
- usual interstitial pneumonia (UIP)
- non-specific interstitial pneumonia (NSIP)
- desquamative interstitial pneumonia (DIP)
- Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD)
Acute IIP
- Cryptogenic organizing pneumonia (COP)
- Acute interstitial pneumonia (AIP)
Non-specific inerstitial pneumonia (NSIP)
Nonspecific interstitial pneumonia (NSIP) can be idiopathic. [1] Also in association with
- connective tissue disease
- HIV infection
- a variety of drugs
- hypersensitivity pneumonitis
. When idiopathic, NSIP is considered one of the idiopathic interstitial pneumonias (IIPs), which include - usual interstitial pneumonia (UIP)/idiopathic pulmonary fibrosis (IPF)
- desquamative interstitial pneumonia (DIP)
- respiratory bronchiolitis-associated interstitial lung disease (RB-ILD)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
Idiopathic NSIP can present alone or in combination with one of the other IIPs.Usual interstitial pneumonia (UIP)
Cryptogenic organizing pneumonia (COP)
Natural History
Lab
Autoantibodies
Imaging
CT
Patterns of HRCT from Uptodate [1]
