Interstitial lung disease

Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of lung diseases affecting the interstitium (the tissue and space around the alveoli (air sacs of the lungs). It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage, but in interstitial lung disease, the repair process goes awry and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The term ILD is used to distinguish these diseases from obstructive airways diseases. Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of lung diseases affecting the interstitium (the tissue and space around the alveoli (air sacs of the lungs). It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage, but in interstitial lung disease, the repair process goes awry and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The term ILD is used to distinguish these diseases from obstructive airways diseases. There are specific types in children. The acronym chILD is used for this group of diseases and is derived from the English name, Children's Interstitial Lung Diseases – chILD. Prolonged ILD may result in pulmonary fibrosis, but this is not always the case. Idiopathic pulmonary fibrosis is interstitial lung disease for which no obvious cause can be identified (idiopathic) and is associated with typical findings both radiographic (basal and pleural-based fibrosis with honeycombing) and pathologic (temporally and spatially heterogeneous fibrosis, histopathologic honeycombing, and fibroblastic foci). In 2015, interstitial lung disease, together with pulmonary sarcoidosis, affected 1.9 million people. They resulted in 122,000 deaths. ILD may be classified according to the cause. One method of classification is as follows: Investigation is tailored towards the symptoms and signs. A proper and detailed history looking for the occupational exposures, and for signs of conditions listed above is the first and probably the most important part of the workup in patients with interstitial lung disease. Pulmonary function tests usually show a restrictive defect with decreased diffusion capacity (DLCO). A lung biopsy is required if the clinical history and imaging are not clearly suggestive of a specific diagnosis or malignancy cannot otherwise be ruled out. In cases where a lung biopsy is indicated, a trans-bronchial biopsy is usually unhelpful, and a surgical lung biopsy is often required. Chest radiography is usually the first test to detect interstitial lung diseases, but the chest radiograph can be normal in up to 10% of patients, especially early on the disease process. High resolution CT of the chest is the preferred modality, and differs from routine CT of the chest. Conventional (regular) CT chest examines 7–10 mm slices obtained at 10 mm intervals; high resolution CT examines 1-1.5 mm slices at 10 mmintervals using a high spatial frequency reconstruction algorithm. The HRCT therefore provides approximately 10 times more resolution than the conventional CT chest, allowing the HRCT to elicit details that cannot otherwise be visualized.