What is respiratory fine bronchitis with interstitial lung disease? Mr. Li is 45 years old and is a full-time driver. Recently, he has been feeling short of breath and coughing, and his difficulty in breathing is more obvious when he goes upstairs. At first he thought he was suffering from “bronchitis” and did not pay attention to it, but his condition gradually worsened. So he went to the hospital, and after the doctor’s questioning, Mr. Li revealed his long history of smoking, about 2 packs a day since he was 18 years old. The doctor recommended that he take a high-resolution CT of the chest and do pulmonary function and bronchoscopy. Based on Mr. Li’s medical history and the results of the ancillary tests, the doctor made a diagnosis of respiratory bronchitis with interstitial lung disease (RBILD). Respiratory fine bronchitis is prevalent in smokers. Microscopically it was possible to observe a large number of smokers’ macrophages that phagocytose soot particles in the lungs aggregating in the lumen of respiratory fine bronchioles. Some smokers have severe clinical symptoms with high resolution CT of the chest suggesting fine bronchitis and interstitial lung changes, called respiratory fine bronchitis with interstitial lung disease. Six cases of respiratory fine bronchitis with interstitial lung disease were first reported in 1987, and in 2002 it was classified as a type of idiopathic interstitial pneumonia. The patients had both fine bronchitis and interstitial pneumonia in the lungs. Microscopically the lesions in the lung tissue are lamellar in distribution, and the respiratory fine bronchioles and their surrounding air spaces contain large numbers of macrophages that phagocytose soot particles, and marked respiratory fine bronchitis and widened alveolar septa are seen, usually without fibrosis or cellular lung. What are the clinical manifestations of respiratory fine bronchitis with interstitial lung disease? Respiratory clinical manifestations usually lack specificity and are characterized by a dry cough, progressive dyspnea that worsens with activity, usually without fever, hemoptysis, or weight loss, making it difficult to differentiate symptomatically from other diseases. How is respiratory fine bronchitis with interstitial lung disease diagnosed? The vast majority of patients have a history of smoking, with a smoking volume of more than 30 pack-years (number of packs per day × number of years of smoking); clinical manifestations include dry cough and dyspnea; bronchoalveolar lavage fluid shows a large number of macrophages that swallow soot particles; high-resolution CT of the chest shows diffuse distribution of bronchial wall thickening, lobular central nodular shadow or diffuse ground glass shadow; in addition to other possible diseases such as pneumoconiosis, allergic After excluding other possible diseases such as pneumoconiosis, allergic pneumonia, drug-related lung injury, alveolar hemorrhage, etc., the diagnosis of this disease is considered. The exact diagnosis requires a surgical lung biopsy for histopathological diagnosis. How is respiratory bronchiectasis with interstitial lung disease treated? Smoking cessation is the primary treatment measure. Most patients improve to varying degrees after quitting smoking, and the ground glass shadow and lobular central nodules on HRCT of the chest diminish or disappear. Mr. Li in the above case history quit smoking immediately based on his doctor’s advice, and his shortness of breath and cough symptoms gradually decreased. When he was reexamined six months later, the high-resolution CT of the chest showed a reduction in lung lesions and a recovery in lung function indicators. Patients with significantly impaired lung function and progressive disease required glucocorticoid therapy, and most of the patients were able to control their disease and improve their chest imaging and lung function indicators. The duration of treatment depends on the efficacy, and the dose can be reduced, maintained or discontinued after the condition improves or stabilizes. What is the prognosis for respiratory bronchiectasis with interstitial lung disease? Most patients have a good prognosis. In a small number of patients, symptoms and lung function may worsen even after smoking cessation and glucocorticoid administration.