Asthma is a reversible airway inflammation and airway spasm that recurs under the influence of endogenous or extrinsic stimuli, and can cause expiratory dyspnea characterized by obstruction of small airways. Long-term diagnosis and treatment can cause irreversible narrowing and damage of the airway.
The prevalence of asthma in people over 20 years old in mainland China is 4.2%. Asthma exacerbations include upper respiratory tract infections, exercise, sinusitis, gastroesophageal reflux, or exposure to soot or other irritating gases, and patients may have a history of wheezing, cough, shortness of breath, chest tightness, and nocturnal symptoms. Be careful to ask about the frequency, duration, medications used, and whether there are concomitant conditions such as dermatitis or allergic rhinitis.
Physical examination
pulse, blood pressure, respiratory rate, body temperature, oxygen saturation; presence of nasal mucosal edema, increased nasal discharge, nasal polyps; rapid expiratory respiratory rate, breathing dyspnea, prolonged expiratory phase, deep end-expiratory wheezing, crackles, rapid heart rate, thoracic hyperdistention; Whether there are non-specific dermatitis or eczema-like changes in the skin, etc.
Diseases that need to be differentiated
(1) Upper respiratory tract diseases: such as upper respiratory tract mass, edema, stenosis, foreign body aspiration, etc., and the dyspnea caused by upper respiratory tract diseases is mainly inspiratory dyspnea. Asthma, on the other hand, is predominantly characterized by expiratory dyspnea.
(2) Lower respiratory tract diseases: dyspnea/wheezing caused by chronic obstructive pulmonary disease, lung mass, pneumonia, other pulmonary/bronchial/pleural diseases, etc., chronic obstructive pulmonary disease causes irreversible decline in lung function, which is different from reversible lung function changes that are basically normal in the non-exacerbative phase of asthma. A medical history, physical examination, chest x-ray, and other tests can also help identify causes.
(3) Differentiation of other systemic/systemic diseases: Differentiation of dyspnea caused by pulmonary and systemic changes in cardiac insufficiency, uremia or rheumatic diseases. History, physical examination, laboratory tests, and other ancillary tests can help differentiate.
diagnosis
History of reversible dyspnea, typical pulmonary signs. Among the pulmonary function, a positive bronchodilator test (FEV1 in lung function is measured 20 minutes after inhalation of bronchodilator, if it increases by 12% compared with before medication, and the absolute value increases by more than 200ml, it is positive, or the average daily PEF diurnal variation rate for 7 consecutive days is greater than 10%, or the PEF weekly variation rate is greater than 20%, indicating reversible changes in the airway. An oxygen saturation test (which can be done with a portable pulse oximeter) can help diagnose asthma and determine the severity of asthma. A chest x-ray is done if necessary to rule out other cardiopulmonary disorders. Primary care doctors can prepare pulse oximeters and peak velometers for patients. Other tests include complete blood tests, allergen-specific IgE antibodies, exhaled nitric oxide tests, etc.
Goal of treatment
Asthma is well controlled, and medication side effects are reduced. Good asthma control criteria: not regularly affected by asthma symptoms, short-acting β agonist use for less than 2 days/week (excluding use for the prevention of exercise-induced asthma); No nocturnal awakenings, no absenteeism from work or school affected by asthma, and satisfaction with treatment for individuals and families.
Specific treatment
1. Find and avoid allergens
2. Patient education: Learn about asthma diseases, medication and self-monitoring
3. Gradual drug treatment in the non-acute exacerbation phase to achieve good control, if not well controlled, escalate to the next step of treatment.
Step 1: Short-acting β agonists as needed; Should not exceed 3-4 times a day (see below for specific medications and doses)
Step 2: Low-dose inhaled corticosteroids plus short-acting β-receptor agonists as needed; (Other treatment options: leukotriene modulators plus short-acting β agonists as needed)
Step 3: Low-dose inhaled glucocorticoids-formoterol for maintenance and remission therapy (preferred); (Other treatment options: intermediate-dose inhaled glucocorticoids plus short-acting β-receptor agonists as needed, or low-dose inhaled glucocorticoids as needed with long-acting bronchodilators, or daily low-dose inhaled corticosteroids with long-acting anti-M receptor antagonists, or daily low-dose inhaled corticosteroids plus leukotriene modulators, and short-acting β-receptor agonists as needed)
Step 4: Medium-dose hormone inhaler - formoterol for maintenance and remission therapy (preferred); (Other treatment options: daily medium-dose inhaler-inhaled glucocorticoids, or medium-dose inhaled corticosteroids plus long-acting anti-M receptor antagonists, or daily medium-dose inhaled corticosteroids plus leukotriene modulators, and short-acting β-receptor agonists as needed)
Step 5: Moderate to high-dose inhaled corticosteroids - long-acting bronchodilation plus long-acting anti-M receptor antagonists and short-acting β agonists as needed (preferred), or moderate- to high-dose hormonal inhalers - long-acting bronchodilation plus leukotriene modulators and short-acting β agonists as needed. Consider biologics.
Commonly used drugs and dosage specific practical methods:
(1) Use short-acting β receptor agonists as needed: 100 micrograms/spray of albuterol aerosol, 1-2 sprays/time, which can be repeated every 4-6 hours. If the daily dosage is more than 4 times and does not relieve, you should go to the hospital for follow-up
(2) Long-acting β receptor agonists: formoterol (such as formoterol 4.5 micrograms, twice a day, inhaled), generally combined with glucocorticoid inhalers.
(3) Inhaled glucocorticoid drugs: beclomethasone, budesonide, fluticasone; Beclomethasone aerosol: small dose 100-250 micrograms/day, medium dose: 250-500 micrograms/day, large dose: 500 micrograms-1000 micrograms/day; Fluticasone aerosol: low dose 125 to 250 mcg/day, medium dose: 250 to 500 mcg/day, high dose: 500 mcg-1000 mg/day
(4) Long-acting β receptor agonists and inhaled glucocorticoid combination inhalers: salmeterol fluticasone inhalers (50 micrograms/100 micrograms, 50 micrograms/250 micrograms, 50 micrograms/500 micrograms) and formoterrobide inhalers (4.5 micrograms/80 micrograms, 4.5 micrograms/160 micrograms), etc
(5) Leukotriene regulator: montelukast (10 mg/time, once a day, oral);
4. Treatment of acute asthma exacerbation:
(1) Short-acting β receptor agonist: albuterol 2.5-5 mg/time, nebulized inhalation, repeated every 20 minutes for a total of 3 times; Then it can be 2.5 mg every 1-4 hours, nebulized. Inhaled and oral or injectable corticosteroids are added at the same time. or albuterol aerosol 100 micrograms/spray, 4 to 8 sprays/time, can be given every 20 minutes, and can be repeated as necessary within 4 hours, and then every 1 to 4 hours, if necessary.
(2) Inhaled glucocorticoids: As mentioned above, they can start with high and high doses, and gradually reduce the dose after the condition stabilizes
(3) Oral/intravenous glucocorticoids: such as prednisone 40-60 mg/day, once a day or orally in two parts, 3-7 days, short-term use can be directly discontinued. The drug needs to be tapered and discontinued for a long time; After discontinuation, it can be changed to inhaled corticosteroid maintenance; prednisolone injections, etc.
(4) Treatment of other intercurrent diseases (e.g., plus antibiotics for respiratory tract infections, etc.)
(5) Oxygen inhalation: Usually after the above treatment, the patient's airway spasm will improve, inflammation will be reduced, and blood oxygen saturation will be improved. If the oxygen saturation is < 90%, oxygen should be inhaled, because it is difficult for primary hospitals/rural doctors to measure blood carbon dioxide concentration in time, so low-flow oxygen is recommended to prevent blood carbon dioxide retention.
(6) If the condition continues to be unrelieved or aggravated, timely referral will be made.
Ya-jian
Deputy Chief Physician of General Medicine (Family Medicine).
Master of Emergency Medicine, China Medical University
Academic: He has been invited by Capital Medical University, China Medical University and other medical universities and general practice training and education institutions to provide general medicine knowledge and general practice training. He has served as an interpreter and translator for many national conferences in general practice. He is a member of the editorial board of the Chinese Journal of General Practice, and a columnist of the column of "General Practitioner's Clinic". Participated in the compilation of "Theory and Evidence-based Practice of General Medicine" and "Training Materials for General Practitioners".