Interstitial lung disease
Citation, DOI, disclosures and article data
At the time the article was created Jeremy Jones had no recorded disclosures.View Jeremy Jones's current disclosures
At the time the article was last revised Muthla Abdulmanan Mohamed had no financial relationships to ineligible companies to disclose.View Muthla Abdulmanan Mohamed's current disclosures
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.
Interstitial lung disease is considered a misnomer by some, as many of the diseases also involve the alveolar spaces.
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.
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:
organic dusts (causing hypersensitivity pneumonitis)
inorganic dusts (causing pneumoconioses)
gases or fumes
Eliciting a history of underlying systemic disease is also helpful since they may involve the lungs in a diffuse and infiltrative manner. Examples include:
inherited diseases, e.g. neurofibromatosis
autoimmune and collagen vascular diseases (collagen vascular disease related interstitial pneumonitis) 3
Where a cause is not determined, the idiopathic interstitial pneumonia (IIP) should be considered:
non-specific interstitial pneumonia (NSIP): non-smokers
cryptogenic organizing pneumonia (COP): previously termed BOOP
desquamative interstitial pneumonia (DIP): end-state of RB-ILD
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.
Follow up and monitoring will depend on a multitude of factors such as symptoms and other co-morbidities etc. While no strict consensus recommendations are available in relation to imaging follow-up for patients with progressive fibrosing forms, many consider an HRCT at the patient’s initial presentation and then every 12–18 months to assess for progression dependent on symptoms etc 11.