Chest ImagingChronic diffuse infiltrative lung disease
(CDILD),
infiltration of the
pulmonary interstitium and/or alveolar spaces by inflammatory cells, fibrous tissue, or other tissues or substances (e.g.
thoracic amyloidosis,
alveolar proteinosis,
alveolar microlithiasis). The abnormalities present may be reversible or irreversible.
Diffuse infiltrative lung disease represents a heterogeneous group of diseases, with a wide range of associated histological abnormalities, treatment and prognoses. Common causes of
diffuse infiltrative lung disease include
sarcoidosis,
idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis), collagenvascular diseases (e.g.
rheumatoid lung disease and
progressive systemic sclerosis), pneumoconioses (e.g.
asbestosis,
silicosis,
coal workers pneumoconiosis),
bronchiolitis obliterans organizing pneumonia, and
hypersensitivity pneumonitis, but more than a hundred different causes of
diffuse infiltrative lung diseases have been described.
Diffuse infiltrative lung disease have a yearly incidence estimated to be between 25 and 30 per 100,000 people, and account for as many as 15% of all patients referred to pulmonologists for evaluation.
Although the clinical presentations of these different diseases vary, most have in common the presence of progressive dyspnoea and restriction on pulmonary function tests. Plain radiographs and HRCT can show a variety of abnormalities depending on the disease present, including findings of fibrosis and honeycombing, small and large nodules, increased lung opacity characterized by ground glass opacity or consolidation, and cystic lesions (see lung cyst). HRCT is more sensitive, specific and accurate in diagnosing diffuse infiltrative lung disease.
RW