Respiratory bronchiolitis-interstitial lung disease
Respiratory bronchiolitis interstitial lung disease (RB-ILD) is a smoking related interstitial lung disease closely related to respiratory bronchiolitis, but demonstrating more severe histological, imaging and clinical findings.
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Epidemiology
In all cases, RB-ILD is typically associated with heavy smoking (usually of 30 pack-years or more) and is often seen in young middle-aged patients (30-40 years of age).
Clinical presentation
Presentation tends to be with progressive shortness of breath and chronic cough 4. Inspiratory crackles are heard in up to half of patients. Clubbing is rare 1.
Pathology
On lung biopsy, pigment-laden macrophages are found within alveoli, and peribronchial inflammation noted. Unlike simple respiratory bronchiolitis, fibrosis extends beyond the tissues immediately adjacent to respiratory bronchioles and extends into alveolar septae.
Histologically RB-ILD is very similar to desquamative interstitial pneumonia (DIP) and many authors feel that the two conditions are closely related, or even variants of the same condition 3. It has even been suggested that DIP should be abolished altogether, and simply thought of as end-stage/severe RB-ILD 5.
Radiographic features
CT
- ground glass opacities: may have a slight upper zone predilection 9
- poorly defined centrilobular nodules
- no particular distribution with both upper and lower zones potentially affected
- if advanced, fibrosis may be evident typically affecting the subpleural regions and more so in the lower lung zones
- patchy areas of hypoattenuation (~40%) with a lower lung predominance 10
- other changes related to smoking
- bronchial wall thickening: can be central +/- peripheral
- centrilobular emphysema
Treatment and prognosis
Usually, no treatment is required other than giving up smoking.
History and etymology
It was first described in 1974 by the American pulmonologist Dennis E Niewoehner (fl. 2019) and colleagues 11,13.
Differential diagnosis
On HRCT appearances consider:
-
non-specific interstitial pneumonitis (NSIP)
- changes of fibrosis: lung volume loss, reticular opacities, and traction bronchiectasis
- ground glass opacities has a random distribution
- acute or subacute hypersensitivity pneumonitis (HP)
See also
Related Radiopaedia articles
Chest
- imaging techniques
-
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
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
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approach
- HRCT
-
chest x-ray
- airways
- bronchitis
- small airways disease
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bronchiectasis
- broncho-arterial ratio
- related conditions
- differentials by distribution
- narrowing
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tracheal stenosis
- diffuse tracheal narrowing (differential)
-
bronchial stenosis
- diffuse airway narrowing (differential)
-
tracheal stenosis
- diverticula
- pulmonary edema
-
interstitial lung disease (ILD)
- drug-induced interstitial lung disease
-
hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
- 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
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
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
-
adenocarcinoma
- pre-invasive tumors
- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
- adenosquamous carcinoma
- 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
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
-
non-small-cell lung cancer