Nocturnal asthma

Introduction to nocturnal asthma Night and early morning wheezing are the most common symptoms in asthma patients. Often from midnight to early morning, you can start with a severe cough, no sputum or less sputum, followed by asthma attacks, patients wheezing, shortness of breath, severe cyanosis, sweating, changing the seat from the lying position without reducing asthma symptoms When the condition is heavier, the wheezing sound can be heard without a stethoscope. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: pneumothorax mediastinal emphysema pulmonary edema

Nocturnal asthma cause

(1) Causes of the disease

The causes of nocturnal asthma are complex, except for the subjective factors such as the patient's own "genetic quality", immune status, mental state, endocrine and health status, allergens, viral infections, occupational factors, climate, drugs, exercise and Environmental factors such as diet are also important causes of asthma development.

(two) pathogenesis

To explore the pathophysiological changes of nocturnal asthma, it is necessary to involve phase biology, that is, the time-related rhythm expressed in biological processes. Asthma has typical phase biological characteristics, and 24 hours of day and night rhythm is very important for asthma. The effect of sleep itself on breathing has been relatively clear. Its effect is that the ventilation is slightly reduced, the blood oxygen level is lowered, the driving to the respiratory center is reduced, and there is no obvious adverse effect in normal people, but in chronic airway diseases. In particular, asthma patients have changes, sleep can affect the regulation of the respiratory center, airway resistance and muscle contraction, the respiratory center has reduced reactivity to chemical, mechanical and cortical impulses during sleep, and respiratory muscles feel respiratory The central impulse is also reduced. The respiratory muscles in the respiratory muscles are more affected than the diaphragm muscles. Due to the decrease in the activity of the intercostal muscles, the thoracic effect on the respiratory phase during the rapid eye movement phase (REM) is better than the awake period and non-fast. The eye movement phase (NREM) is to be reduced, and both the REM and NREM sleeps are noticed with a decrease in functional residual capacity (FRC). The main effect of sleep on breathing is the change of airway resistance, which is the main stimulator of nighttime airway contraction. Most normal human airway diameters have periodic changes day and night, accompanied by mild nighttime bronchoconstriction. The contraction effect is amplified in asthma patients, which shows that PEF can decrease by 50%, and it changes rapidly with the change of sleep time, while the normal person's mutation rate averages about 8%.

Mechanisms that cause nighttime airway contraction in asthmatic patients:

1. Changes in autonomic tone: increased parasympathetic tone of the heart and bronchial tension during sleep, this change is related to changes in the circadian rhythm of airway function, and can be blocked by anticholinergic drugs in nocturnal asthma patients. The degree of airway contraction is greatly reduced, but it will not be eliminated. Morrison et al. can increase PEF at 4 o'clock in the morning after injection of atropine in asthmatic patients at night, and it is considered that hyperactivity of cholinergic tone is a major cause of nocturnal asthma.

Another nervous system is also distributed on the bronchial smooth muscle, the non-adrenergic, non-cholinergic (NANC) system, and nitrous oxide (NO) is the neurotransmitter of NANC. Recently there is evidence that NANC is in the early morning. The expansion of the bronchus is inhibited, and the bronchoconstriction by the parasympathetic nerves at night and the decrease in the bronchodilation of the NANC are reduced. The result of the regulation of the bronchial tone balance by the nervous system tends to bronchoconstriction.

2. Changes in airway inflammation: In the past, people have noticed an increase in plasma histamine levels in asthmatic patients. Currently, they mainly focus on changes in airway inflammation in bronchoalveolar lavage fluid (BALF) and bronchial biopsy in nocturnal asthma patients. Acidic granulocytes, macrophages and neutrophils play an important role. Martin et al reported that the number of leukocytes, neutrophils and eosinophils in BALF at 4 o'clock in the morning was higher than that at 4 o'clock in the afternoon. Mackay et al also found early morning. At 4 o'clock, eosinophils increased in BALF, and eosinophil cationic protein (ECP) also increased. In addition to eosinophils, lymphocytes also participated in the inflammatory process of asthma. In patients with severe asthma, IL was expressed. The number of T lymphocytes (Tc) in the -2 receptor was significantly increased. After allergen challenge, the peripheral blood Tc aggravated the inflammatory response to the lung parenchyma. In nighttime asthma patients, the Tc was also significantly increased in BALF at 4 o'clock in the morning. The study suggests that the inflammatory activity in the airway of patients with nocturnal asthma increases in the early morning, and the stimulating factors are still unclear. It may be related to changes in autonomic tone, which may cause changes in bronchial blood flow. , Endothelial hyperpermeability can also make easy inflammatory cells into the bloodstream, and other factors that may be hormone related and catecholamine levels decreased, resulting in persistent neurological bronchoconstriction.

3. Changes in hormone levels: It has been found that changes in respiratory resistance in patients with nocturnal asthma are related to changes in the circadian rhythm of some hormones in the body. The changes in day and night rhythm of cortisol are most typical, and the peak concentration of blood appears in waking, while the concentration in the valley is at midnight. Although normal people and asthma patients have corticosteroid circadian rhythm changes, nocturnal asthma can not be completely attributed to the reduction of nocturnal cortisol concentration, but due to the antagonistic effect of cortisol on chronic airway inflammation, the concentration of cortisol at night Decreased is one of the important factors of nocturnal asthma. In addition, the catecholamine level also has a rhythm of day and night. Injecting a physiological dose of adrenaline to nocturnal asthma patients can reduce the decrease of PEF to a certain extent. In addition to relaxing bronchial smooth muscle, adrenaline can inhibit mast cells. The release of histamine and other mediators, so the decline in adrenaline also promotes nocturnal asthma.

4. Beta adrenergic receptor decline: -adrenergic receptor density in nocturnal asthma patients decreased in response to isoproterenol at 4 am, a phenomenon associated with 2 adrenergic receptor polymorphism At the Argl6 site, the frequency of change was increased and the beta receptor function was down-regulated.

5. Reduction of lung volume: FRC decreases during sleep, causing passive contraction of the bronchus. There is evidence that decreased FRC in asthma patients can cause bronchoconstriction during sleep and continue to awake, which will form a nighttime airway in patients with nocturnal asthma. .

6. Hysteria: The incidence of snoring in asthma patients is higher than that in normal people. It may be associated with rhinitis in asthma patients, resulting in increased nasal resistance. The negative pressure of the pharynx is greater when inhaling, and some patients may have airway stenosis. Others such as supine position, gastroesophageal reflux, and prolonged time interval of nighttime medication may have a certain relationship with nocturnal asthma. Therefore, the occurrence of nocturnal airway contraction is multifactorial, whether it occurs in normal or asthma patients. However, asthma patients are more prominent in the presence of external stimuli and underlying factors.

The results of nighttime airway stenosis can worsen the symptoms of asthmatic patients at night or early morning, causing acute attacks, affecting the quality of life of their own and family members, often requiring night visits, poor sleep quality, daytime activity, and more importantly, nocturnal asthma. Recurrence of symptoms suggests that the disease is not controlled, which may be related to inadequate control of asthma inflammation, but may also be associated with increased airway responsiveness due to airway remodeling in patients with chronic persistent asthma.

Night asthma prevention

1. It is necessary to actively eliminate the cause and prevent acute attacks, which are closely related to asthma attacks and infections, allergens, air pollution and mental factors.

2. Mental factors are closely related to asthma attacks and remission. Nighttime dreams can induce asthma or worsen the condition. Therefore, avoiding mental stimulation is very important for preventing asthma attacks.

Nocturnal asthma complications Complications, pneumothorax, mediastinal emphysema, pulmonary edema

Can be combined with hypoxemia, pneumothorax, mediastinal emphysema, severe acute pulmonary edema.

Symptoms of asthma at night Common symptoms Bronchial smooth muscle spasm, difficulty breathing, wheezing

Often from midnight to early morning, you can start with a severe cough, no sputum or less sputum, followed by asthma attacks, patients wheezing, shortness of breath, severe cyanosis, sweating, changing the seat from the lying position without reducing asthma symptoms When the condition is heavier, the wheezing sound can be heard without a stethoscope.

Nighttime asthma checkup

Laboratory tests: Patients with severe illness may have a reduction in PaO2.

Other auxiliary examinations: patients with forced vital capacity asthma have a long-term tolerance to symptoms, and objective examination of respiratory function is especially important for the assessment of the disease. Before the nap, the nighttime wake-up and the early morning, the peak speed meter dynamically measures the maximum call. Air flow (PEF), while PEF was measured at noon to determine the best respiratory function status of the day as a baseline value.

Through the dynamic observation of the humerometer, you can understand the state of asthma, take correct treatment, can avoid the wrong judgment caused by one measurement at the time of diagnosis, so comprehensively evaluate the daytime and nighttime status, and when the patient is in a stable period, the dynamic hornometer Monitoring can often indicate changes in the condition, and patients should be reminded in time. Usually, patients with asthma have an acute attack. PEF can gradually decrease in a few days, and the variation of PEF is increased. It can be treated or treated in time. Suspected and have a sleep pause. Syndrome patients need to perform nighttime sleep monitoring.

Nighttime asthma diagnosis

diagnosis

Asthma patients have symptoms at night, and it is usually difficult to diagnose. However, for middle-aged and old-aged asthma, it is often accompanied by other diseases such as heart disease, COPD, etc. Therefore, attention should be paid to the diagnosis and cardiac asthma, and COPD night wheezing is intensified. And repeated small pulmonary embolism to identify, in fact, most diseases have day and night rhythm changes, nighttime symptoms worsen, so when certain diseases affect the upper airway (such as allergic rhinitis) and lower airway, the symptoms will also Confused with nocturnal asthma.

Differential diagnosis

Attention should be paid to the identification of cardiogenic asthma, increased COPD nighttime wheezing, and recurrent small pulmonary embolism.

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