pulmonary fibrosis



OVERVIEW

Definition

Pulmonary fibrosis is an end-stage pathological change that results from abnormal repair of lung tissue after injury from various causes.

It is characterized by proliferation of fibroblasts and their transformation into myofibroblasts, accumulation of large amounts of extracellular matrix and inflammation, and destruction of lung tissue structure. Aggregation and inflammatory reaction, lung tissue structure destruction is characterized.

Pulmonary fibrosis is not a disease, but a pathological change that occurs in many end-stage lung diseases.

Morbidity

Overall: There are no results of a large-scale epidemiologic survey of pulmonary fibrosis, but there is a clear trend of increasing incidence of pulmonary fibrosis in general.

Prevalence: The prevalence of specific pulmonary fibrosis in the general population ranges from 2/100,000 to 29/100,000, with onset in middle-aged or older individuals, and is more common in older males who are heavy smokers (>20 packs/year).

Causes

Causes

Related diseases: Lungs are an important site of systemic diseases, including rheumatoid arthritis, scleroderma, dry syndrome, inflammatory myelopathy, systemic lupus erythematosus and other autoimmune diseases may cause pulmonary fibrosis; gastroesophageal reflux disease (GERD) may also cause pulmonary fibrosis due to the irritation of refluxed material to the airways.

Medications: Certain medications may damage the lungs and cause pulmonary fibrosis, including chemotherapeutic drugs such as methotrexate and cyclophosphamide, and newer tumor-targeting and immunologic drugs, amiodarone for arrhythmia, certain antibacterials (furotoxin or ethambutol, sulfadiazine), and propylthiouracil for hyperthyroidism.

Radiation therapy: Irradiation of the lungs while undergoing chest radiation therapy may lead to damage to the lungs, which may result in the development of pulmonary fibrosis.

Genetic factors: While familial pulmonary fibrosis is rare, certain mutations in the telomerase gene may be associated with familial idiopathic pulmonary fibrosis.

Environmental exposure to harmful substances: Pulmonary fibrosis may be induced by long-term exposure to harmful substances and polluted air. Examples include smoking or exposure to secondhand smoke, dust, asbestos fibers, metal dust, and bird or other animal feces.

Viral infections: EBV and Hepatitis C virus infections can induce pulmonary fibrosis.

Accidental consumption of paraquat: Paraquat enters the body and triggers acute lung injury, which then induces pulmonary fibrosis.

No clear cause: in addition to the above factors, there are some pulmonary fibrosis without finding a clear cause. The disease that causes this type of pulmonary fibrosis is called idiopathic interstitial pneumonia, in which idiopathic pulmonary fibrosis is an important type of disease that causes pulmonary fibrosis.

Pathogenesis

When lung tissue is damaged for various reasons, structural damage occurs and “scar tissue” grows, resulting in stiffness, poor elasticity, and difficulty in passing gas.

Excessive accumulation of inflammatory cells in the lungs and inflammatory exudation make the lungs even more inelastic, making gas passage even more difficult.

Failure to remove the damaging factors, inhibit the inflammatory response, or impair the repair function will result in even more structural damage to the lungs, further scar tissue growth, structural damage to the lungs, and an inability to perform the “breathing” function, which will result in symptoms due to a lack of oxygen.

Symptoms

Main Symptoms

Lung fibrosis affects the normal gas exchange function of the alveoli, resulting in the following respiratory symptoms:

Unrelieved dry cough.

Difficulty in breathing, which gets progressively worse.

Other symptoms

Patients with pulmonary fibrosis may also have a variety of systemic symptoms.

Fatigue and weakness.

Weight loss.

Feeling of pressure in the chest.

Bluish-purple lips and finger/toe nails.

Pestle-like fingers, where the tips of the fingers and toes become rounded and widened.

Complications

Respiratory failure: When the tissue in the lungs undergoing fibrosis gradually increases, the lung function further decreases and respiratory failure can occur, which is manifested by dyspnea, decreased blood pressure, arrhythmia, coma, and cardiac arrest.

Pulmonary arterial hypertension: there are no obvious symptoms in the early stage of pulmonary arterial hypertension, but in the middle and late stage, patients will have palpitation, and in serious cases, heart failure, dyspnea, lower limb edema and so on can occur.

Lung cancer: long-term pulmonary fibrosis will increase the risk of lung cancer. Lung cancer patients usually present clinical symptoms such as cough, chest tightness and chest pain.

Consultation

Department of Medicine

Respiratory Medicine

Prompt medical consultation is recommended when there is dry cough, dyspnea, fatigue and weakness, or obvious changes in the color of the nails of the mouth and lips.

Emergency Department

If you experience strong discomfort after exercise, immediate medical attention is recommended.

Preparation for medical treatment

Preparation for medical consultation: registration, preparation of documents, frequently asked questions

Tips for the doctor

Chest X-rays or chest CT are often needed, so avoid wearing clothing made of metal, and inform your doctor if you are pregnant or planning to become pregnant.

Preparation Checklist

Pay particular attention to the time of onset of symptoms and special signs and symptoms.

Is there difficulty in breathing?

Is there chest pain? Is it worse with activity?

Have you lost weight recently?

Is there a cough? Any phlegm?

How long have the symptoms been present?

Have you been smoking heavily for a long time?

What is your occupation? Have you been exposed to large amounts of dust, asbestos fibers, etc. for a long time?

Are you taking medications such as methotrexate, cyclophosphamide, etc., or have you received radiation therapy to the chest?

Does anyone in the family have pulmonary fibrosis?

Test results in the last six months, which can be brought to the doctor’s office

Laboratory tests: blood tests, liver and kidney functions

Imaging: Chest X-ray, Chest CT scan

Others: blood oxygen test, lung function test, bronchoscopy

Medication in the last 3 months, if available, bring the box or package with you to the clinic.

Anti-fibrotic drugs: pirfenidone, nidaneb

Glucocorticoids: prednisone, methylprednisolone

Others: methotrexate, cyclophosphamide, omeprazole, ranitidine, thalidomide

Diagnosis

Diagnosis is based on

Medical history

There may be a history of environmental and occupational exposures, connective tissue disease, related drug use, or radiation therapy.

There may be a family history of idiopathic pulmonary fibrosis.

Clinical manifestations

The patient has chest tightness, cough, fatigue and weakness, hypoxia, mortar and pestle fingers, and progressively worsening dyspnea.

Blood test

Blood tests can determine the function of the liver and kidneys, and exclude some infectious diseases.

Imaging examination

Chest CT examination: Compared with ordinary X-ray examination, CT examination can better observe the changes in the lungs, and can accurately determine the scope and degree of pulmonary fibrosis with high sensitivity and specificity.

Echocardiography: Echocardiography can show a visual image of the heart and is used to assess the function of the heart. Echocardiography is required for cardiac evaluation because pulmonary fibrosis predisposes to pulmonary hypertension and right heart failure.

Pulmonary Function Tests

Pulmonary function testing will involve a series of non-invasive tests that can help your doctor determine how well your lungs are functioning and whether there is any ventilation dysfunction.

Oximetry

An instrument will need to be worn on the fingertips or ears for testing blood oxygen levels to determine if there is a lack of oxygen.

Bronchoscopy

Bronchoscopy is performed to find out the conditions related to the lungs. In addition, bronchoscopy allows for biopsy of lung tissue or bronchoalveolar lavage, where the lavage fluid is examined, and can help in the differential diagnosis of disease.

Biopsy

Histopathologic examination of tissues removed by bronchoscopy, thoracoscopy, direct fine-needle aspiration, or surgery is used to identify pathologic changes.

Differential Diagnosis

Pneumonia

Similarities: symptoms of shortness of breath and cyanosis of the lips and nails.

Differences: Pneumonia may have systemic symptoms such as fever and chills, while pulmonary fibrosis is a non-infectious disease, and the two can be combined with blood gas analysis and pathogenetic examination for differential diagnosis.

Lung cancer

Similarities: cough, sputum, chest pain, dyspnea, weakness. Interstitial changes of lungs can be seen in imaging examination.

Differences: Lung cancer can be clinically differentiated by chest CT, bronchoscopy and sputum exfoliative cytology.

Chronic obstructive pulmonary disease

Similarity: cough, sputum, dyspnea symptoms.

Differences: COPD can be seen as pulmonary pustules on imaging, which is easier to differentiate from pulmonary fibrosis. When the imaging is atypical, it is necessary to combine with medical history and lung function to make a differentiation.

Treatment

Principles of treatment

There is no treatment that can reverse the fibrosis that has already appeared in the lung tissues, but medication can help to slow down the progression of fibrosis and reduce clinical symptoms.

Lung transplantation may be considered in patients with severe pulmonary fibrosis.

Treatment

Medication

Pirfenidone: used to treat idiopathic pulmonary fibrosis.

Nidanib: Used in the treatment of idiopathic pulmonary fibrosis (IPF), it can inhibit the development of pulmonary fibrosis.

This class of drugs reduces the inflammatory response and, in combination with other immunosuppressants (cyclosporine, azathioprine, etc.), slows the progression of pulmonary fibrosis caused by certain types of disease. Commonly used drugs are prednisone and methylprednisolone.

Generally used in combination with glucocorticoids to treat pulmonary fibrosis caused by certain types of diseases and to slow the progression of the disease.

Commonly used drugs include cyclophosphamide, azathioprine, mycophenolate mofetil, tacrolimus, cyclosporine, methotrexate, hydroxychloroquine, and sirolimus.

These drugs have adverse effects such as gastrointestinal toxicity or myelosuppression, and care should be taken during administration.

Pulmonary fibrosis is often accompanied by gastroesophageal reflux, and gastroesophageal reflux can be treated with antacid drugs. These drugs include proton pump inhibitors (e.g. omeprazole, esomeprazole, pantoprazole, etc.) and H2 receptor antagonists (e.g. ranitidine, famotidine, nizatidine, etc.), which can alleviate the symptoms of gastroparesis caused by gastroesophageal reflux accompanied by pulmonary fibrosis, such as gastric pain, heartburn and acid reflux.

Dry cough is a common symptom of pulmonary fibrosis. Conventional cough suppressants are usually helpful in relieving the symptoms, and for stubborn and severe cough, application of low-dose thalidomide may be considered.

The therapeutic effect of TCM on pulmonary fibrosis needs to be confirmed by evidence-based medical evidence. Clinical practice suggests that combining TCM may be helpful in improving patients’ conditions, reducing adverse drug reactions, and improving immunity, and appropriate TCM should be selected and matched according to the dialectical results of each patient.

Surgery

Lung transplantation may be required when fibrosis severely affects respiratory function.

Suitability for lung transplantation needs to be assessed by a doctor. The doctor may need to consider the overall physical condition, the presence of other serious illnesses, and the ability to accept the risks of the surgery.

Lung transplants can be performed on one side of the lung or on both sides of the lung. Both breathing capacity and survival may improve after transplantation.

Lung transplantation is usually a general anesthesia procedure that takes 4 to 8 hours for unilateral lung transplantation and 6 to 12 hours for bilateral lung transplantation.

Hospitalization is required for recovery after surgery, along with breathing exercises and slow, deep breathing.

Doctors will evaluate graft rejection after surgery, and it is possible that long-term anti-rejection medications may be needed.

Prognosis

Cure

Pulmonary fibrosis is a potentially fatal disease with a poor prognosis, and there are no medications that can reverse fibrotic lung tissue.

Aggressive treatment with medications can be effective in slowing the progression of lung fibrosis, relieving symptoms, and improving quality of life.

Lung transplantation significantly prolongs survival.

Early diagnosis and aggressive treatment can prolong survival.

Hazards

Survival time varies with different causes of pulmonary fibrosis.

If left untreated, the disease progresses more rapidly and survival is compromised.

Respiratory failure is the most common cause of death.

Daily

Daily Management

Dietary management

Avoid spicy and stimulating, fried and greasy foods as well as fish, shrimp and eggs. The above foods are prone to produce phlegm, leading to coughing up phlegm and coughing, etc. Particular attention should be paid to coughing, coughing up phlegm or manifestation of infection.

Avoid foods that cause inflammation and drink plenty of water. Drinking water can dilute phlegm and promote phlegm discharge.

Avoid alcohol, quit smoking, and avoid inhaling harmful substances (dust, wood dust, etc.).

Diet should be well-balanced and light. Low-fat foods, fruits and vegetables should be the mainstay of the diet, and a light diet can reduce the formation of phlegm. Eat lean meat in moderation.

Eat more almonds, white radish, sweet almonds, lotus root, yam or lotus seed, etc. which have the effect of moisturizing and preserving the lungs or relieving cough and phlegm.

Maintain nutrition by choosing high-protein foods such as lean meat, animal liver, tofu and soy milk to promote further health. Prevent symptoms such as malnutrition and respiratory muscle weakness caused by insufficient protein intake.

High-fiber and high-vitamin diets such as carrots, pumpkin, apricots, jujubes, grapefruit, green peppers, tomatoes, etc. can be chosen to prevent respiratory infections.

Patients with severe pulmonary fibrosis can be given soft food or semi-fluid food when they have difficulty in chewing and swallowing due to respiratory urgency. It helps to reduce pain and facilitates digestion and absorption, and also prevents food reflux.

Exercise management

Total Body Exercise: Physical exercise helps to develop good mood and energy. You can start with an amount of exercise that suits you and exercise two to four times a week for 20 to 40 minutes.

Breathing exercises: Relax your neck and arm muscles and breathe in through your nose for 2 seconds, then pucker your lips and exhale for 4 seconds. Try to slow down your breathing while exercising and focus your attention on the puckering and exhaling process.

Others

Oxygen therapy

Avoid strenuous physical labor, avoid crowded places to avoid cross infection.

Due to occupational fatalities, stay away from dusty environments and allergens.

Regular review for monitoring.

Prevention

Quit smoking and stay away from second-hand smoke.

Avoid exposure to occupational dust, metal dust, wood dust, etc.

Regular lung imaging should be done during immune disorders and application of radiotherapy drugs.

During radiotherapy treatment, you should follow the doctor’s instructions to take proper protective measures.

Pay attention to keep warm and prevent cold, avoid respiratory tract infection.

Strengthen physical exercise to enhance physical fitness.