Interstitial lung disease
Interstitial lung disease (ILD) is an umbrella term that encompasses a large number of disorders that are characterized by diffuse cellular infiltrates in a periacinar location. The spectrum of conditions included is broad, ranging from occasional self-limited inflammatory processes to severe debilitating fibrosis of the lungs.
On this page:
Terminology
Interstitial lung disease is considered a misnomer by some, as many of the diseases also involve the alveolar spaces.
Clinical presentation
Interstitial lung diseases classically produce the "3Cs": cough, clubbing of the nails, and coarse crackles on auscultation 6.
Functional respiratory tests commonly show an abnormal restrictive pattern and reduced diffusing capacity.
Pathology
Etiology
The radiological appearances are not specific for the underlying cause of diffuse lung disease in many cases. It is therefore key to determine whether there is an underlying cause for the changes. A number of precipitants can cause diffuse interstitial disease such as:
- smoking 1
- organic dusts (causing extrinsic allergic alveolitis)
- inorganic dusts (causing pneumoconioses)
- gases or fumes
- drugs
- radiation
- infection
Eliciting a history of underlying systemic disease is also helpful since they may involve the lungs in a diffuse and infiltrative manner. Examples include:
- granulomatous diseases, e.g. sarcoidosis, Langerhans cell histiocytosis
- neoplasia
- primary, e.g. lymphoma, other lymphoproliferative diseases
- secondary, e.g. pulmonary metastases, lymphangitis carcinomatosis
- vasculitis
- inherited diseases, e.g. neurofibromatosis
- autoimmune and collagen vascular diseases 3
- systemic lupus erythematosus
- rheumatoid arthritis
- progressive systemic sclerosis
- anti-Jo-1 antibody positive interstitial lung disease
- ankylosing spondylitis
- Sjögren syndrome
- mixed connective tissue disease
- psoriasis - pulmonary manifestations of psoriasis
- interstitial pneumonia with autoimmune features
- miscellaneous, e.g. amyloidosis, alveolar proteinosis
Where a cause is not determined, the idiopathic interstitial pneumonia (IIP) should be considered:
- usual interstitial pneumonia (UIP): idiopathic pulmonary fibrosis
- cryptogenic organizing pneumonia (COP): previously termed BOOP
- non-UIP IIP
- non-specific interstitial pneumonia (NSIP): non-smokers
- respiratory bronchiolitis-interstitial lung disease (RB-ILD): smokers
- desquamative interstitial pneumonia (DIP): end-state of RB-ILD
- lymphoid interstitial pneumonia (LIP): women
- acute interstitial pneumonitis (AIP)
- other entities
Mnemonic: All Idiopathic Chronic Lung Diseases aRe Nonspecific
Radiographic features
The diffuse lung diseases tend to cause infiltrative opacification in the periphery of the lung, but patterns vary among the different etiologies. Please refer to the articles in each specific etiology listed above for specific details on their imaging pattern.
See also
- interstitial lung abnormality
- interstitial lung pattern - radiograph
Related Radiopaedia articles
Chest
- imaging techniques
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chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
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-
lines and stripes
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- posterior junction line
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- left paratracheal stripe
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- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
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- spaces
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approach
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chest x-ray
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bronchiectasis
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tracheal stenosis
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bronchial stenosis
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tracheal stenosis
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interstitial lung disease (ILD)
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hypersensitivity pneumonitis
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- subacute hypersensitivity pneumonitis
- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
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- tobacco grower’s lung
- potato riddler’s lung
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- dry rot lung
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- humidifier lung
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- miller’s lung
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idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
-
pneumoconioses
- fibrotic
- non-fibrotic
-
lung cancer
-
non-small-cell lung cancer
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adenocarcinoma
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- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
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- large cell carcinoma
- primary sarcomatoid carcinoma of the lung
- squamous cell carcinoma
- salivary gland-type tumors
-
adenocarcinoma
- pulmonary neuroendocrine tumors
- preinvasive lesions
-
lung cancer invasion patterns
- tumor spread through air spaces (STAS)
- presence of non-lepidic patterns such as acinar, papillary, solid, or micropapillary
- myofibroblastic stroma associated with invasive tumor cells
- pleural invasion
- vascular invasion
- tumors by location
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- pulmonary metastases
- lung cancer screening
- lung cancer staging
-
non-small-cell lung cancer