From the Guidelines
Reticulonodular changes in the lower lobes of the lungs are most commonly caused by idiopathic pulmonary fibrosis, which creates a progressive scarring pattern, as evidenced by the most recent and highest quality study 1. The causes of reticulonodular changes in the lower lobes of the lungs can be diverse, including:
- Interstitial lung diseases, such as idiopathic pulmonary fibrosis and sarcoidosis
- Infections, including pneumocystis pneumonia, tuberculosis, and fungal infections like histoplasmosis
- Occupational exposures to substances such as silica, asbestos, and coal dust, leading to pneumoconiosis with reticulonodular patterns
- Hypersensitivity pneumonitis from allergen exposure
- Pulmonary edema from heart failure
- Lymphangitic carcinomatosis from metastatic cancer
- Connective tissue diseases like rheumatoid arthritis and scleroderma Diagnosis typically requires:
- Chest imaging (X-ray and high-resolution CT)
- Pulmonary function tests
- Sometimes bronchoscopy with bronchoalveolar lavage or lung biopsy Treatment depends on the underlying cause, ranging from:
- Corticosteroids for inflammatory conditions
- Antimicrobials for infections
- Supportive care for chronic progressive diseases It is essential to note that the diagnosis and treatment of reticulonodular changes in the lower lobes of the lungs should be guided by the most recent and highest quality evidence, such as the study published in 2022 1, to ensure the best possible outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Causes of Reticulobodular Changes in the Lower Lobes of the Lung
- Reticulobodular changes in the lower lobes of the lung can be caused by various conditions, including hypersensitivity pneumonitis (HP) 2, 3, 4, 5.
- HP is an immune-mediated interstitial lung disease caused by an aberrant response to an inhaled exposure, resulting in T cell-mediated inflammation, granuloma formation, and fibrosis in some cases 4.
- The presence of reticulation on initial imaging is an independent predictor of radiological progression in subpleural nonfibrotic interstitial lung abnormalities 6.
- Chronic hypersensitivity pneumonitis can cause reticulobodular changes in the lower lobes of the lung, characterized by a bronchiolocentric chronic interstitial inflammatory infiltrate, frequently with associated granulomas or giant cells 2.
- Other conditions, such as pulmonary sarcoidosis, can also cause reticulobodular changes in the lower lobes of the lung, but the pattern and distribution of lung parenchymal abnormalities on high-resolution computed tomography scans can help differentiate among these diseases 3.
Key Features of Reticulobodular Changes
- Reticulation is a key feature of reticulobodular changes, and its presence is a risk factor for radiological progression in subpleural nonfibrotic interstitial lung abnormalities 6.
- Centrilobular nodules and mosaic attenuation are also common features of HP, and can be seen on high-resolution computed tomography scans 4.
- The absence of lower lung zone predominance is characteristic of chronic HP, whereas idiopathic pulmonary fibrosis or usual interstitial pneumonia typically shows honeycombing with lower lung zone predominance 3.
Diagnosis and Treatment
- Diagnosis of HP is based on an accurate exposure history, clinical presentation, characteristic high-resolution CT findings, specific IgG antibodies to the offending antigen, bronchoalveolar lavage, and pathological features 5.
- Complete antigen avoidance is the mainstay of treatment for HP, and pharmacotherapy may include immunosuppressive drugs such as corticosteroids, with antifibrotic therapy being a potential therapy for patients with progressive disease 5.