Interstitial lung disease (ILD) is a group of lung disorders characterized by inflammation and scarring (fibrosis) of the interstitial tissue, which is the tissue that surrounds and supports the air sacs (alveoli) in the lungs. This inflammation and scarring cause stiffness in the lungs, impairing their ability to expand and contract properly, which leads to difficulty in breathing. ILD encompasses a wide range of conditions, each with its own causes, clinical features, and prognosis.
Some common types of ILD include:
- Idiopathic Pulmonary Fibrosis (IPF): IPF is the most common and well-known type of ILD. It is characterized by progressive scarring of the lung tissue of unknown cause. IPF typically affects older adults and has a poor prognosis.
- Hypersensitivity Pneumonitis: This condition occurs due to an immune reaction to inhaled allergens such as mold, dust, or bird droppings. It can be acute or chronic and is characterized by inflammation and fibrosis of the lung interstitium.
- Connective Tissue Disease-associated ILD: ILD can occur in association with various autoimmune diseases, such as rheumatoid arthritis, systemic sclerosis (scleroderma), and dermatomyositis/polymyositis. In these cases, the immune system mistakenly attacks the lung tissue, leading to inflammation and fibrosis.
- Sarcoidosis: Sarcoidosis is a systemic inflammatory disease that can affect multiple organs, including the lungs. In pulmonary sarcoidosis, granulomas (small inflammatory nodules) form in the lung tissue, leading to inflammation and scarring.
- Drug-induced ILD: Some medications, particularly certain chemotherapy drugs and antibiotics, can cause inflammation and fibrosis in the lungs, leading to ILD.
- Occupational Lung Diseases: Exposure to certain occupational hazards, such as asbestos, silica, or coal dust, can lead to ILD. These conditions are often referred to as pneumoconioses.
Symptoms of ILD may include shortness of breath, cough, fatigue, and unexplained weight loss. Diagnosis typically involves a combination of clinical evaluation, pulmonary function tests, imaging studies (such as chest X-ray or high-resolution CT scan), and sometimes lung biopsy.
Management of ILD depends on the underlying cause and may involve medications to suppress inflammation (such as corticosteroids or immunosuppressants), oxygen therapy, pulmonary rehabilitation, and in some cases, lung transplantation. Early diagnosis and treatment are crucial for improving outcomes in ILD.