What Is Bronchial Asthma?

Bronchial asthma is a heterogeneous airway inflammation characterized by a variety of cells (such as eosinophils, mast cells, T lymphocytes, neutrophils, airway epithelial cells, etc.) and cellular components. Qualitative disease, this chronic inflammation is associated with airway hyperresponsiveness, usually with extensive and changeable reversible expiratory airflow limitation, causing recurrent wheezing, shortness of breath, chest tightness and / or cough, etc., intensity Change with time. Attacks and exacerbations occur at night and / or early in the morning, and most patients can resolve on their own or after treatment. If bronchial asthma is not diagnosed and treated in time, the irreversible narrowing of the airway and remodeling of the airway can occur with the prolongation of the disease course.

Basic Information

English name

bronchial asthma

Visiting department

Respiratory

Common locations

bronchus

Common symptoms

Recurrent wheezing, shortness of breath, chest tightness, and / or cough

Contagious

no

Causes of bronchial asthma

Genetic factor

Individual allergies and the influence of the external environment are risk factors for disease. Asthma is related to polygene inheritance. The prevalence of relatives in asthma patients is higher than the prevalence in the population. The closer the relationship is, the higher the prevalence. The more severe the patient's condition, the higher the prevalence of relatives.

Allergen

(1) Indoor and outdoor allergens Dust mite is the most common and most harmful indoor allergen. It is an important cause of asthma worldwide. Dust mites are present in secretions such as fur, saliva, urine and feces. Fungi are also one of the allergens that exist in indoor air, especially in dark, humid, and poorly ventilated places. Common outdoor allergens: Pollen and grass powder are the most common outdoor allergens that cause asthma attacks, and other specific and non-specific inhalants such as animal hair debris, sulfur dioxide, and ammonia.

(2) Occupational allergens Common allergens Original grain flour, flour, wood, feed, tea, coffee beans, silkworm, pigeons, mushrooms, antibiotics (penicillin, cephalosporin), rosin, reactive dyes, persulfuric acid Salt, ethylenediamine, etc.

(3) Drugs and food Aspirin, propranolol (propranolol) and some non-corticosteroid anti-inflammatory drugs are the main allergens of drug-induced asthma. In addition, fish, shrimp, crab, eggs, milk and other foods can also induce asthma.

3. Trigger factors

Common air pollution, smoking, and respiratory infections, such as bacterial, viral, protozoan, and parasitic infections, pregnancy, strenuous exercise, and climate change; a variety of non-specific stimuli such as inhalation of cold air, distilled water mist, etc. can induce asthma attacks. In addition, mental factors can induce asthma.

Clinical manifestations of bronchial asthma

Paroxysmal dyspnea accompanied by wheezing or paroxysmal cough and chest tightness. Severe cases are forced to take a seated or end-to-end breath, dry or cough a lot of white foamy sputum, and even cyanosis. Sometimes cough is the only symptom (cough variant asthma). Some adolescent patients have chest tightness, cough, and dyspnea during exercise as their only clinical manifestations (exercise asthma). Asthma symptoms can occur within minutes, and after hours to days, they can be relieved with bronchodilators or spontaneously. Some patients can relapse after several hours of remission. Night and morning attacks and exacerbations are often a feature of asthma.

Bronchial asthma examination

Physical examination

The onset of the chest was over-inflated, the thorax was swollen, and the percussion was hyperphonic. Most of them had extensive wheezing based on exhalation and prolonged exhalation. Severe asthma attacks often have signs such as strenuous breathing, sweating, cyanosis, abnormal movements of the chest and abdomen, increased heart rate, and odd pulses. There may be no abnormal signs during the remission period.

2. Laboratory and other inspections

(1) Routine blood test Some patients may have eosinophilia during the onset, but most of them are not obvious. If they are complicated by infection, there may be an increase in the number of white blood cells, and the proportion of classified neutrophils will increase.

(2) Sputum examination smears There are more eosinophils. If combined with respiratory bacterial infection, sputum smears with Gram staining, cell culture and drug sensitivity tests can help diagnose and guide the treatment of pathogenic bacteria.

(3) Pulmonary function examination Most of the pulmonary ventilation functions during remission are in the normal range. At the onset of asthma, due to the limited expiratory flow rate, the expiratory flow rate indicators have decreased significantly, manifested as forced expiratory volume in the first second (FEV1), one-second rate (FEV1 / FVC%) (forced expiratory volume in 1 second) Occupied vital capacity ratio), maximum mid expiratory flow rate (MMER), maximum expiratory flow (MEF50% and MEF75%) at 50% and 75% expiratory capacity, peak expiratory flow (PEFR), and maximum expiratory flow ( PEF). Lung capacity indicators can effectively reduce vital capacity, increase residual capacity, functional residual capacity, and total lung capacity, and increase residual gas percentage in total lung capacity. It can gradually recover after treatment. If the lesion is prolonged and repeated, the ventilation function may gradually decrease.

(4) Blood gas analysis Due to airway obstruction and uneven ventilation distribution during severe asthma, the ventilation / blood flow ratio imbalance can cause the alveolar-arterial oxygen partial pressure difference (A-aDO2) to increase; hypoxia, PaO ₂ and SaO ₂ decreased. PaCO ₂ decreased and pH increased due to hyperventilation, which showed respiratory alkalosis. Such as severe asthma, further development of the condition, severe airway obstruction, hypoxia and CO ₂ retention, PaCO ₂ rise, showing respiratory acidosis. If hypoxia is obvious, metabolic acidosis can be combined.

(5) Chest X-ray examination During the early stage of asthma attacks, the transillumination of both lungs can be seen to increase, showing an over-inflated state; there is no obvious abnormality during the remission period. Such as concurrent respiratory infections, increased lung texture and inflammatory infiltrates can be seen. At the same time, attention should be paid to complications such as atelectasis, pneumothorax, or mediastinal emphysema.

(6) Detection of specific allergens Most patients with asthma are associated with allergies and are sensitive to numerous allergens and irritants. Determination of allergic indicators combined with medical history can help diagnose the patient's etiology and exposure to allergens. However, allergic reactions should be prevented.

(7) Others Skin skin allergen test, inhalation allergen test, and specific IgE of patients that can be detected in vitro can be done as appropriate.

Bronchial asthma diagnosis

For patients with typical symptoms and signs, except for wheezing, shortness of breath, chest tightness, and cough caused by other diseases, a clinical diagnosis can be made; for atypical cases, bronchodilatation or provocation tests should be performed, and the positive can be confirmed.

Differential diagnosis of bronchial asthma

1. Asthmatic dyspnea caused by left heart failure

More common in older people. The reasons are: hypertension, coronary arteriosclerosis, mitral valve stenosis or chronic nephritis, etc., the attacks are more common at night. Symptoms are chest tightness, shortness of breath and difficulty, cough and wheezing, severe cases with cyanosis, gray complexion, cold sweats, nervousness and fear, similar to an acute attack of asthma. In addition to wheezing, patients often have a large amount of thin watery or foamy sputum or pink foamy sputum, and typical wet base snoring sounds. The heart enlarges to the left, heart valve murmurs, and heart sounds may be irregular or even Running horse law. The chest X-ray shows that the heart shadow may be enlarged. In patients with mitral valve stenosis, the left atrial appendage is often enlarged. The lungs show signs of pulmonary edema, and blood vessels are blurred. Due to pulmonary edema, the leaf interval becomes wider, and the leaf interval line can be moved down to the basal lung lobe, which is helpful for identification.

2. Chronic obstructive pulmonary disease

More common in middle-aged and elderly people, with a history of chronic cough, wheezing persists throughout the year, and there is an exacerbation period. Most patients have a history of long-term smoking or exposure to harmful gases, emphysema signs, and both lungs may be audible and wet rales. However, it is sometimes difficult to strictly distinguish chronic obstructive pulmonary disease from asthma clinically. Therapeutic diagnosis with bronchodilators, oral or inhaled hormones may be helpful, and sometimes both can coexist.

3. Allergic pulmonary infiltration

This is a group of pulmonary eosinophilic diseases, including simple eosinophilic pneumonia, persistent eosinophilic pneumonia, asthmatic eosinophilic pneumonia, tropical pulmonary eosinophilia, and pulmonary necrotizing vasculitis. Diseases can be included in this group of diseases, they may have asthma symptoms, especially asthmatic eosinophilic pneumonia is particularly obvious. The disease can be seen at any age, and most are associated with bacterial infections of the lower respiratory tract. The patient is allergic to Aspergillus, so it is also called allergic bronchopulmonary aspergillosis. Patients often have fever, and chest X-rays show multiple, thin patches of infiltrating shadows that can disappear or recur on their own. Lung biopsy can help identify.

4. Trachea and main bronchial lung cancer

Due to cancer compression or invasion of the trachea or main bronchi, the upper airway lumen is narrowed or incompletely blocked, coughing or wheezing, or even wheezing. However, patients usually do not have a history of asthma, expectoration can be bloody, wheezing symptoms are mostly inspiratory dyspnea, or wheezing is limited, and asthma medication is not effective. As long as the disease is taken into consideration, further chest X-ray examination, CT, sputum cytology, and fiberbronchoscopy are not difficult to identify.

Bronchial asthma treatment

There are no effective treatments at present, but long-term standardized treatment can keep asthma symptoms under control, reduce recurrence or even no more outbreaks.

Treatment goal

(1) Complete control of symptoms;

(2) To prevent the onset of or worsening of the disease;

(3) Lung function is close to the optimal value of the individual;

(4) Normal activity ability;

(5) Improve self-awareness and ability to deal with acute exacerbations, and reduce the chance of emergency department or hospitalization;

(6) Avoid adverse drug reactions;

(7) Prevent irreversible airway obstruction;

(8) Prevent death from asthma.

2. Basic clinical strategies for the prevention and treatment of asthma

(1) Long-term anti-inflammatory treatment is the basic treatment, and inhaled hormones are preferred. Commonly used inhaled drugs are beclomethasone (BDP), budesonide, fluticasone, mometasone, etc. The latter two are more biologically active and have a longer lasting effect. It usually takes inhalation for more than a week to take effect.

(2) The drug of choice for emergency relief of symptoms is inhaled 2 agonists. 2 agonist mainly activates adenylate cyclase by stimulating 2 receptors in the respiratory tract, which increases the content of cyclic adenosine monophosphate (cAMP) in the cell and reduces free Ca, thereby relaxing bronchial smooth muscle. It is the first choice for controlling acute asthma drug.

(3) If the condition is not satisfactory after regular inhalation of hormones, it is advisable to add inhaled long-acting 2 agonists, or slow-release theophylline, or leukotriene modulators (combined drugs); consider increasing the amount of inhaled hormones.

(4) In patients with severe asthma, intensive treatment may be considered when they have recurrent episodes after long-term treatment. That is, according to the treatment of severe asthma, large doses of hormones and other treatments are given. After the symptoms are completely controlled, the optimal level of pulmonary function is restored, and the PEF fluctuation rate is normal, the dosage of hormones is gradually reduced after 2 to 4 days. Some patients have satisfactory disease control after intensive treatment.

3. Therapeutic measures for comprehensive treatment

(1) Eliminate the cause and cause.

(2) Prevention and treatment of co-existing diseases, such as allergic rhinitis and reflux esophagitis.

(3) Immunomodulatory therapy.

(4) Regularly check whether the inhaled medicine is used correctly and follow the doctor's order.

Prognosis of bronchial asthma

The outcome and prognosis of asthma varies from person to person and is closely related to the correct treatment plan. Childhood asthma can reach 95% clinical control rate through active and standardized treatment. It is easy to recover from mild disease, severe condition, obvious increase of airway responsiveness, or difficult to control with other allergic diseases. If prolonged episodes are complicated by chronic obstructive pulmonary disease (COPD) and pulmonary heart disease, the prognosis is poor.

Education and management of bronchial asthma

The education and management of asthma patients is an important measure to improve efficacy, reduce recurrence, and improve the quality of life of patients. Doctors should develop a prevention and treatment plan for each newly diagnosed asthma patient, so that patients understand or master the following:

1. Believe that asthma attacks can be effectively controlled through long-term, appropriate and adequate treatment;

2. Understand the motivating factors of asthma, combine each person's specific situation, find out their own stimulating factors, and ways to avoid incentives

3. Briefly understand the nature and pathogenesis of asthma;

4. Familiar with the symptoms of asthma attacks and the corresponding treatment methods;

5. Learn to monitor the changes of your own condition at home and make assessments. Focus on mastering the use of the peak flow meter, and record your asthma diary if possible;

6. Learn to perform simple emergency self-management methods when asthma attacks;

7. Understand the functions, correct dosage, usage and adverse reactions of commonly used asthma drugs;

8. Master the correct usage of different inhalation devices;

9. Know when to go to the hospital for treatment;

10. Work with your doctor to develop a plan to prevent recurrence of asthma and maintain long-term stability.