Idiopathic pulmonary fibrosis in the elderly

　　The etiology of idiopathic pulmonary fibrosis in the elderly is unclear. Risk factors may include smoking, antidepressants, gastroesophageal reflux, occupational exposure to dust, viral infection, and congenital (familial pulmonary fibrosis), etc.

　　Idiopathic pulmonary fibrosis in the elderly has many and severe complications, including pulmonary infection, hemoptysis, spontaneous pneumothorax, emphysema, pulmonary hypertension, chronic pulmonary heart disease, respiratory failure, and pulmonary encephalopathy. As the disease progresses, dyspnea may occur even at rest, and severe patients may experience progressive dyspnea. Other symptoms include dry cough and fatigue. 50% of patients have clubbing and cyanosis, and fine crackling sounds can be heard at the end of inspiration at the base of the lung. Although dyspnea may occur in the early stage, chest X-rays may appear normal; in the middle and late stages, there may be diffused reticular or nodular shadows in the middle and lower lungs, and occasionally pleural effusion, thickening, or calcification. The serious consequences of pulmonary tissue fibrosis lead to changes in the normal structure of the lung tissue and loss of function.

　　Progressive worsening of dyspnea is the most common symptom of this disease, accounting for 84% to 100%, and the progression speed of dyspnea varies from person to person, generally entering respiratory insufficiency and affecting activity within 1 to 3 years.

　　Another common symptom is an irritating dry cough, which is often severe, and when accompanied by pulmonary infection, it can have symptoms such as fever, cough with sputum, purulent sputum, and is often accompanied by fatigue, anorexia, weight loss, and sometimes joint pain.

　　Patients with idiopathic pulmonary fibrosis (IPF) in the elderly often show symmetrical shrinkage of both pleural cavities, flattened chest, and elevated diaphragm. In most patients, continuous, high-pitched crackling sounds (Velcro rales) can be heard in the lower lungs; clubbing and toes appear earlier; in the late stage, hypoxia and cyanosis occur, and oxygen therapy does not significantly improve hypoxia; patients are more comfortable in a lateral or supine position than in a sitting or standing position, and dyspnea is reduced, which is obviously different from hypoxia caused by chronic obstructive pulmonary disease.

　　Since the symptoms and signs of IPF are non-specific, it is important to differentiate it from other pulmonary interstitial diseases during diagnosis, which is both important and difficult. Detailed inquiries into the medical history are very important, such as occupational history, whether there is a history of engaging in related professions such as asbestos exposure; life history, such as allergies to poultry breeding; and history of exogenous allergic alveolitis. In addition, the clinical characteristics of this disease, such as prominent dyspnea, clubbing, Velcro rales, and imaging and pulmonary function tests with abnormal findings can be used for an initial diagnosis. Under the condition of the disease, TBLB and BAL examinations can be performed, and most patients can obtain a diagnosis.

　　The prevention of idiopathic pulmonary fibrosis in the elderly should focus on the secondary pulmonary fibrosis caused by known etiologies for prevention and treatment. For example, in connective tissue diseases such as rheumatoid arthritis, systemic sclerosis, Sjögren's syndrome, and systemic lupus erythematosus, active treatment of the primary disease and prevention of complications, such as pulmonary fibrosis, are important. For drug-induced pulmonary fibrosis, those caused by allergies should be immediately discontinued and appropriately treated, with a good prognosis. Those caused by cytotoxic reactions have a poorer prognosis. However, once drug-induced pulmonary fibrosis is diagnosed, it should be immediately discontinued and corticosteroid treatment should be administered. Due to the potential to cause pulmonary fibrosis from inhaling organic dust or toxic gases, health education should be provided to those engaged in related professions, and labor protection should be done well to minimize the inhalation of harmful gases or organic dust. If there are clinical symptoms, stop contact and apply corticosteroid treatment, and the condition and X-ray shadows will improve significantly.

　　The laboratory tests for elderly patients with idiopathic pulmonary fibrosis mainly include hematology tests, which are manifested as: increased erythrocyte sedimentation rate, increased immunoglobulin, but without differential diagnostic significance; various immunological indicators of collagen vascular diseases are helpful for their diagnosis and differential diagnosis.

　　Other auxiliary examinations include the following three aspects:

　　1. Chest X-ray plain film changes

　　Early IPF patients may show hazy, ground-glass-like density increase shadows in both lower lung fields, indicating the pathological basis of alveolar infiltrative lesions, which is a characteristic radiographic manifestation of alveolitis. As the course of the disease progresses, linear streak-like textures appear within the lung fields, resembling intricate fine grids, known as reticular shadows. In the late stage, coarse lines and coarse reticulation appear, and when the alveoli are atelectasis, the small bronchi compensate for expansion into cystic, surrounded by a large amount of fibrous connective tissue, honeycomb lung appears on chest X-rays. Most have no mediastinum, enlargement of hilar lymph nodes, and the pleura is not invaded, but it often causes pneumothorax due to rupture of bullae.

　　2. Chest CT

　　Due to the absence of tissue structural overlap in CT and its high resolution, CT has also been applied in the diagnosis of IPF in recent years, especially high-resolution CT (HRCT), which is significantly better than chest X-rays and conventional CT. HRCT can detect interstitial fibrosis in the lungs without abnormal findings on chest X-rays, and is helpful in analyzing the morphology, distribution, and severity of the lesions. HRCT should be performed selectively, usually in three planes, namely, at the level of the aortic arch, the bifurcation of the trachea, and 1cm above the diaphragm, which can represent the pathological conditions of three lung fields to reduce radiation dose. HRCT examination shows irregular linear changes, accompanied by cystic small air spaces. When there are patchy alveolar infiltrative hazy shadows, it reflects the activity of inflammatory lesions. Thickenings of the interlobular pleura are also a common sign of IPF. Since CT can clearly show the mediastinum and pleura, it can provide a basis for differential diagnosis with some interstitial diseases that are prone to invade this area. CT can show small, medium-sized nodules and reticular nodules, and sometimes large areas of high-density lesions can be seen, among which twisted and constricted or dilated airways can be observed. In the late stage, honeycomb lung appears, and there is localized emphysema near large areas of fibrosis, which is manifested as increased air content locally and sparse lung vascular shadows, irregular thickening of the pleura, especially in the middle and lower lungs, showing a diffuse distribution.

　　3. Pulmonary function examination

　　Routine pulmonary function tests can reveal restrictive pulmonary dysfunction, with some airway obstruction, which is very helpful in distinguishing from obstructive airway diseases, and the pulmonary function test of IPF is characterized by restrictive ventilation impairment.

　　Currently, there is no effective preventive measure for idiopathic pulmonary fibrosis in the elderly, and there are no special dietary requirements. It is recommended to have a light diet, eat more vegetables and fruits, reasonably match the diet, pay attention to sufficient nutrition; avoid smoking, alcohol, and spicy food.

　　Once diagnosed with idiopathic pulmonary fibrosis in the elderly, regardless of acute, chronic, early, or late stages, corticosteroid treatment should be considered first. If hormones are used early, it can reduce the occurrence of alveolitis, promote the absorption of exudate and cell components, and prevent fibrosis. Corticosteroids can regulate the inflammatory and immune processes, reduce the content of immune complexes, improve the function of alveolar macrophages, indirectly affect the function of T lymphocytes, and reduce the chemotactic factors produced by alveolar macrophages.

　　1. Corticosteroids
　　Although it is the first choice for treatment, the effect is not satisfactory, with an effective rate of 15% to 50%, averaging about 20%.
　　The use of prednisone (Prednisone) currently has no universally recognized treatment plan that has been proven through prospective controlled studies, and treatment is mostly based on clinical experience. The initial and treatment dose can be 1-1.5mg/(kg/d) orally, and if clinical symptoms improve 2-3 weeks later, gradually reduce to 30-40mg/d, closely observe for 3-6 months, and if the condition is stable, gradually reduce to 15-30mg/d, maintain for 1 year or longer. The treatment of idiopathic pulmonary fibrosis (IPF) with corticosteroids, some patients cannot control the condition, and at this time, it can be combined with azathioprine or cyclophosphamide. A series of reports have suggested that adding or switching to such drugs in patients with ineffective corticosteroid treatment may have some effect, but whether it is a treatment plan, dosage combination, etc., more planned prospective clinical experience is needed.

　　2. Cyclophosphamide (CTX)
　　The general dose is 100-150mg/d orally, or 400mg intravenous injection once a week, or 200mg intravenous twice a week. The total dose can reach 8-12g, and the white blood cell count should be kept above 4000/mm3.
　　Methotrexate is convenient for oral administration, 10mg taken once a week orally.

　　3. Other:Lung transplantation has been listed as a recognized treatment plan for completely treating pulmonary fibrosis, and some technologically advanced countries have carried it out and achieved effects.