Environmental factors refer to all kinds of allergens, including irritating gases, virus infection, climate, drugs, exercise, food, etc., which may become the inducement of asthma.
Allergens are an important cause of asthma. Allergens can be divided into human allergens and human allergens. Human allergens include dust, dust mites, pollen, fungi and animal fur shavings; Carnivorous allergens are mainly foreign proteins, such as fish, shrimp, meat, eggs and other animal proteins.
Both human inhalant allergens and human feeding allergens belong to exogenous allergens. When exogenous allergens enter the human body for the first time, people with allergic constitution can produce a large number of immunoglobulin E, such as reagin, which can be fixed on mast cells of bronchial mucosa. When the human body is exposed to the same allergen again, the allergen will combine with immunoglobulin E fixed on the surface of bronchial mast cells, and the two will react. This antigen-antibody reaction will destroy mast cells. Releasing a variety of bioactive substances, such as slow-response allergic substances SRS-A, histamine, bradykinin, serotonin, etc., leads to bronchial smooth muscle spasm, lumen stenosis, mucosal edema, excessive secretion of mucus glands, and leads to asthma attacks.
There is also an allergen from the body, such as the metabolites of bacteria or viruses, which is also a cause of this disease. Metabolites of these bacteria or viruses urge B cells to produce antibodies, such as precipitate or immunoglobulin M, which combine with corresponding allergens to form antigen-antibody complexes, which deposit under bronchial mucosa, destroy granulocytes with the participation of antibodies, release slow-response allergic substance SRS-A, cause bronchospasm, increase mucus secretion, and lead to asthma attacks.
Most asthma patients are caused by mixed allergens inside and outside.
People with allergies are prone to asthma. There is a disease in dermatology called atopic dermatitis, which is an allergic skin disease such as urticaria and eczema that occurs in asthma patients. In fact, this is also a manifestation of asthma, which is closely related to primary asthma. If asthma is controlled, atopic dermatitis will get better.
No matter what causes asthma, it will make bronchiole smooth muscle spasm, mucosal swelling, increased secretion, poor lung ventilation and expiratory dyspnea; Due to the stenosis of bronchiolar cavity, the ventilation resistance is obviously increased, which makes the alveoli over-inflated and temporary emphysema appears. After the bronchospasm was relieved, asthma was controlled and emphysema disappeared.
Clinical manifestations: Before the onset of asthma, the patient's throat itched or sneezed, and he felt chest tightness, cough, expectoration and dyspnea during the attack. Dyspnea is more obvious when exhaling, and the attack can last for several minutes to several hours, often at night or in the early morning. If the asthma attack lasts more than 24 hours and can't be controlled, it is called asthma status quo. In the current situation of asthma, in addition to the above symptoms, patients also have symptoms such as pale face, cold sweat, cold limbs, cyanosis, slow breathing, prolonged exhalation, frequent cough and sticky phlegm. If the sputum blocks the bronchus, the auscultation wheezing sound disappears instead, indicating that the condition is critical. If bronchospasm lasts too long, it will also cause respiratory failure and endanger life. The reasons for the persistence of asthma are uncontrolled infection, persistent allergens, phlegm, severe hypoxia and acidosis.
Clinical examination shows that the patient has chest tightness, and the chest has palpated a voiceless sound. During auscultation, wheezing can be heard in the exhalation. When complicated with infection, the lungs can hear wet rales, prolonged exhalation and increased heart rate. Some asthma patients are cyanotic due to lack of oxygen. Laboratory examination showed that the white blood cell count was generally normal and increased when secondary infection occurred. Leukocyte classification increases eosinophils; A large number of eosinophils can also be detected in sputum; X-ray examination showed that the texture of both lungs increased or the light transmittance increased.
Diagnosis of bronchial asthma: According to the symptoms and signs of repeated, sudden, expiratory dyspnea, cough, expectoration, auscultation of the lungs, wheezing, etc., combined with the medical history, such as respiratory tract infection before the attack, or contact with allergens, it is not difficult to diagnose.
The treatment principles of asthma attack are: correcting hypoxia, relieving bronchial smooth muscle spasm, relieving cough and asthma, and preventing secondary infection. The medicine can be Vantorin aerosol, twice each time; Pulmicort aerosol, 2-4 sprays each time; Hydroxypropyl theophylline 1-2 tablets, 2-3 times a day; Antibiotics can be used for secondary infections. Asthma state should be given oxygen inhalation to correct hypoxia and improve hypoxia; Besides aerosol, other drugs, such as bronchodilators, antibiotics and adrenocortical hormones, should be injected intravenously to relieve bronchial smooth muscle spasm as soon as possible and improve the persistent symptoms of wheezing.
Asthma patients should exercise properly in the stable period to enhance their physique and improve their reaction ability. At the same time, we should try our best to find out allergens, carry out desensitization treatment, and also prevent respiratory tract infections and remove infected lesions in the body. With the improvement of physical fitness, the number of asthma attacks decreases accordingly.