What Is Interstitial Lung Disease?

Interstitial lung disease (ILD) is based on diffuse pulmonary parenchyma, alveolar inflammation, and interstitial fibrosis as pathological basic lesions, with active dyspnea, diffuse infiltration shadows on chest radiographs, restrictive ventilation disorder, and diffuse ) Reduced function and hypoxemia are the general term for clinical-pathological entities composed of different disease groups with clinical manifestations.

Basic Information

nickname: Diffuse lung disease
English name: ILD
Visiting department: Respiratory
Common locations: Lungs

Common causes: The etiology is unknown and related to pneumoconiosis and other factors.
Common symptoms: Progressive exertional shortness of breath, dry cough, twitching sounds or wet murmurs at the end of inspiration in both lower lungs, clubbing fingers, chest radiograph showing diffuse mesh-like shadows of both lungs.

Causes of interstitial lung disease

The etiology is mostly unknown. The pathogenic factors that initiate ILD are usually toxins and / or antigens. Known antigen inhalation such as inorganic dust is associated with asbestos lung and pneumoconiosis (pneumoconiosis). Organic dust is associated with exogenous allergic alveolitis. Related, and the specific antigens such as idiopathic pulmonary fibrosis (IPF) and sarcoidosis are unknown.

Clinical manifestations of interstitial lung disease

The typical clinical manifestations of ILD include: progressive exertional shortness of breath, dry cough, end-twisting sounds or wet murmurs of inhalation of both lower lungs, clubbing fingers, and chest radiographs showing diffuse mesh-like shadows of both lungs. Eventually it can lead to severe double lung fibrosis (honeycomb lungs), causing respiratory failure and pulmonary heart disease. There are usually no extrapulmonary manifestations, but there may be some accompanying symptoms such as loss of appetite, weight loss, weight loss, and weakness.

Shortness of breath is the most common first-diagnosis symptom, which is mostly insidious. It starts gradually during more vigorous activities, and gradually worsens, often accompanied by shallow and rapid breathing. Many patients are accompanied by marked fatigue. Most patients with ILD have cough symptoms, mostly dry cough. Individual cases have a small amount of white sputum or white foamy sputum. Chest pain is rare, and individual patients with sarcoidosis complain of sternal pain, which can also be seen in patients with ILD complicated with pleural disease. Wheezing is rare, mainly seen in patients with exogenous allergic alveolitis or eosinophilic pneumonia. Hemoptysis is also rare, mainly seen in diffuse alveolar hemorrhage syndrome, pulmonary vascular disease, and malignant lung disease.

Interstitial lung disease examination

Physical sign

Increased breathing rate is often the earliest manifestation of ILD. Many patients experienced a significant increase in respiratory rate (> 24 beats / minute) after a short period of activity. Double lower lung twist sounds or wet murmurs are enhanced or appear more than inspiratory end, especially in cases of idiopathic pulmonary interstitial fibrosis. However, some diseases (such as sarcoidosis) are mostly free of wet murmurs or twisting sounds. The clubbing finger (toe) is mainly found in patients with ILD caused by idiopathic pulmonary interstitial fibrosis and lung cancer. For other causes of ILD, clubbing fingers (toes) are uncommon.

2. Chest X-ray examination

In most patients with ILD, diffuse shadows on the chest X-ray, or (rarely) nodular interstitial shadows, usually have normal lung volume. Other features include thickened bronchial walls, prominent spaces around the bronchial vessels, small regular or irregular shadows, and small peripheral ring shadows.

3. Lung CT

HRCT is conducive to the detection of early pathological changes, such as irregular line grid-like changes in the lungs, accompanied by the formation of cystic small air cavities, which first appeared under the pleura, and small airways connected to each other can form the subpleural line.

4. Lung function test

Restrictive ventilation dysfunction and reduced diffusion

5.Bronchoalveolar lavage

Bronchoalveolar lavage fluid (BALF) is tested for cytology, etiology, biochemistry, and inflammatory mediators. According to the proportion of inflammatory immune effector cells in BALF, ILD can be classified as lymphocytosis and neutrophil polymorphism. .

6. Lung biopsy

Obtaining lung tissue for pathological examination through bronchial lung biopsy or surgical lung biopsy is an important method for the diagnosis of ILD.

7. Other

Laboratory tests are non-specific changes, such as: arterial blood gas showing hypoxemia, accelerated erythrocyte sedimentation, increased blood lactate dehydrogenase and increased immunoglobulin, and a few patients have positive rheumatoid factor and antinuclear antibodies.

Interstitial lung disease diagnosis

Based on clinical manifestations, chest imaging findings, pulmonary ventilation and diffuse function, pathological biopsy, and exclusion of ILD from other known causes. If necessary, a surgical lung biopsy may be performed.