[Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD)]

Area of Science:

• Pulmonology
• Pathology
• Radiology

Background:

• Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) is a smoking-related lung condition.
• It is characterized by pigmented macrophages and interstitial inflammation, often transitioning to desquamative interstitial pneumonia (DIP).
• RB-ILD is frequently subclinical and diagnosed incidentally in smokers.

Purpose of the Study:

• To describe the histological, radiological, and functional characteristics of RB-ILD.
• To outline diagnostic approaches and differential diagnoses for RB-ILD.
• To discuss the prognosis and management of RB-ILD.

Main Methods:

• Histological examination of lung tissue showing bronchiolocentric pigmented macrophages and interstitial changes.
• High-resolution computed tomography (HRCT) revealing centrilobular nodules, ground glass opacities, and bronchial wall thickening.
• Bronchoalveolar lavage (BAL) and lung biopsy (transbronchial, thoracoscopic, or open) for diagnosis.

Main Results:

• Radiographic findings include reticulonodular and ground glass opacities, with HRCT showing centrilobular nodules and ground glass opacities.
• Lung function tests often show minor restrictive or obstructive defects with hyperinflation and impaired CO diffusing capacity.
• RB-ILD has a favorable prognosis, with lung changes reversing after smoking cessation; corticosteroid therapy is generally not required.

Conclusions:

• RB-ILD is a distinct smoking-related interstitial lung disease with a generally favorable prognosis.
• Smoking cessation is the primary treatment, leading to reversible lung changes.
• Accurate diagnosis requires excluding other interstitial lung diseases, with biopsy often necessary for pronounced cases.