Asthmatic bronchitis in children

Introduction to pediatric asthmatic bronchitis Asthmatic bronchitis (asthmatoid bronchitis) is only a clinical concept. It refers to a group of asthmatic infantile lower respiratory tract infections. It is a clinical syndrome, which refers to a group of asthmatic infants with acute bronchial infection, lung. The substance is rarely affected, and some of the sick children can develop into bronchial asthma. Because the baby's trachea and bronchus are relatively small, it is easy to be aggravated by infection or other stimuli. In addition, the child has allergic factors, causing bronchospasm or swelling after the upper respiratory tract infection, resulting in wheezing, therefore, some people think that part of the disease is infantile bronchial asthma (hereinafter referred to as asthma) or mild asthma . basic knowledge The proportion of children: the incidence rate of children under 6 years old is about 0.02% - 0.04% Susceptible people: young children Mode of infection: non-infectious Complications: pneumonia asthma

Causes of pediatric asthmatic bronchitis

(1) Causes of the disease

There are several factors that can be affected in the following ways:

Infection factor

A variety of viral and bacterial infections can be caused, more common are syncytial virus, adenovirus, rhinovirus and Mycoplasma pneumoniae. In most cases, bacterial infection can occur on the basis of viral infection.

2. Anatomical features

The trachea and bronchus of infants and young children are relatively narrow, and the surrounding elastic fibers are not well developed. Therefore, the mucosa is susceptible to infection or other irritation and swelling and congestion, causing the tube to be narrow, and the secretions are not sticky and easy to discharge, resulting in wheezing sound.

3. Allergies

There are many cases of infants and young children with viral infections. Only a small number of children have asthmatic bronchitis, suggesting that different pathophysiological changes and clinical manifestations of the same virus in different individuals are closely related to the factors in the body, such as recent years. It was found that children with asthmatic bronchitis caused by syncytial virus had gE antibody, and the concentration of histamine in the nasopharyngeal secretion was significantly higher than that of the same infection without wheezing. The relatives often had allergic rhinitis. A history of allergic diseases such as urticaria and asthma, about 30% of children have had eczema, and serum IgE levels are often increased.

(two) pathogenesis

The pathogenesis of asthmatic bronchitis is similar to that of asthma. The pathogenesis of asthma has been studied in recent years, and it can be roughly as follows.

Allergic reaction

It is the main cause of some asthmatic bronchitis and bronchial asthma. The allergic reaction refers to the reactive change of the body in contact with external antigens. This reactive change is a special type of immune response, which can be divided into 4 types, ie, speed. Allergic reaction type, cytolytic type, immune complex type and delayed type. Allergic asthma patients are mainly type I and type II abnormal reactions. Patients with allergic constitutions are exposed to specific antigens and produce reactive antibodies in vivo. Globulin E (IgE), its content in normal human serum is very small (0.01 ~ 0.09mg), specific receptors on the target cell membrane of IgE and bronchial mucosa and submucosal mast cells and blood basophils (per The basophilic cells have 40,000 to 100,000 receptors on the surface to produce sensitization. The bronchial tension is mainly regulated by the changes in the absolute value and ratio of intracellular cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate. Increased cAMP can stabilize mast cells and inhibit the release of chemically active substances. The Fc segment of specific IgE molecules can be strongly adsorbed on the cell surface, and the Fab segment reacts with the antigen (usually two IgE fractions). Combined with an antigen molecule, activates the enzymatic reaction of mast cells, causing the cell membrane calcium channel to open, calcium ions into the cell, and activation of the calcium-binding protein such as calmodulin in the cytoplasm, which activates phosphodiesterase , thereby promoting the hydrolysis of cAMP, due to the decrease of cAMP concentration, the stability of the particles in mast cells is destroyed, leading to the release of degranulation and chemical active substances, such as histamine, slow-reacting substances, bradykinin and eosinophilic super-factor (ECF-A), etc., these media can stimulate the afferent part of the vagus nerve, causing bronchospasm, histamine can increase the permeability of capillaries and cause tissue edema, slow-reactive substances mainly cause persistent bronchoconstriction, ECF-A chooses Attracting eosinophils leads to allergic tissue damage. Studies by the Capital Institute of Pediatrics have confirmed the presence of sputum-specific IgE in the serum of children with asthmatic bronchitis and asthma, and the pollen-specific IgE of Artemisia, considered dust mites and wormwood. Pollen is closely related to asthmatic bronchitis and asthma. Drug-induced asthma such as aspirin can cause asthma, and its pathogenesis Because aspirin inhibits cyclooxygenase, thereby inhibiting the biosynthesis of prostaglandins (PG), especially PGE. Because PG synthesis is blocked, arachidonic acid can synthesize leukotrienes (LT) along the lipoxygenase pathway. Ingredients LTC4, LTD4, LTE4, which is a slow-reacting substance, can cause strong and long-lasting contraction of bronchial smooth muscle. In addition to IgE, it has been found that IgG4, one of the IgG subgroups, can also induce type I allergic reaction, and SIgA is mucosa. Anti-bacterial, immune factors of viral invasion, Beijing Children's Hospital measured the salivary SIgA in children with asthma, the results were significantly lower than normal, suggesting that SIgA deficiency or reduction is closely related to the onset of asthma, infants and young children due to poor ability to synthesize SIgA, easy to get respiratory infection, External antigens also easily enter the body through the respiratory tract, causing an increase in specific IgE in the body, and thus an increase in asthmatic bronchitis and asthma. Recently, it has been suggested that IgG and IgM play a role in the pathogenesis of asthma. When children inhale allergic antigens, Delayed onset asthma response, Gallrame lung biopsy from asthma patients, using fluorescent immunoassay to detect the presence of C3 in the basement membrane of the lung, said Complement and immune complexes involved in the pathogenesis, the first type allergy performance.

2. The role of adrenal receptors

Some people think that the various causes of asthma are increased through a common way, that is, the respiratory tract of asthma patients is increased in response to various incentives. Under low threshold stimulation, smooth muscle spasm can be caused. The respiratory tract is controlled by autonomic nerves. When the vagus nerve is excited, smooth muscles are obtained. Contraction, sympathetic excitation makes the smooth muscle relax, the sympathetic nerve is directly distributed to the bronchus, but distributed to the cholinergic ganglia, which transmits the bronchoconstriction caused by the vagus nerve impulse, mainly through the circulation of catecholamines and abundant receptors. At the present time, it is known that there are at least four receptors in the respiratory tract, namely receptor, receptor, M receptor and H receptor, all of which are related to respiratory function, receptor and H2 receptor. Increased intracellular cAMP content leads to relaxation of bronchial smooth muscle and antagonizes other contractile substances. and M receptors bind to corresponding agonists, respectively, by lowering cAMP levels and increasing cyclic guanosine monophosphate (cGMP) content. To make bronchospasm, HI receptors receive histamine released by mast cells, causing bronchospasm and edema, under normal circumstances It is a receptor, and the density of receptors from the trachea to the peripheral bronchial smooth muscle cells is getting higher and higher, and more than 90% of the receptors are 2 subtypes. Therefore, the bronchial smooth muscle mainly receives the circulating catecholamines by the receptor. The stimulation of the -receptor agonist maintains the diastolic state of the airway, and the receptor often decreases in asthma. There are roughly three theories:

(1) The theory of receptor reactivity reduction.

(2) Receptor transformation theory.

(3) The -receptor autoantibodies theory shows that the adrenergic receptors are most closely related to asthma.

3. Genetic factors

As early as 1650, Sennetus reported that his wife's family had asthma for three consecutive generations. William found that 50% of asthma patients had a history of allergic diseases. The results of the Shanghai Medical University Pediatric Hospital showed that asthma incidence among relatives of asthma children It is obviously higher than the control group, and it tends to increase with the close of the parental family. The closer the parent is, the higher the incidence of asthma, indicating that asthma is closely related to heredity. At present, it is internationally agreed that asthma is a polygenic genetic disease, and the genetic law of the disease is compared. Complex, from the analysis of the family, there are the following characteristics:

(1) The incidence of relatives is often higher than the incidence of the population, and the closer the relationship is, the higher the incidence.

(2) In a family, the more the number of patients, the higher the incidence of relatives, and vice versa.

(3) In a family, if the patient's condition is more serious, the incidence of his relatives is higher, and vice versa.

(4) When the incidence of a certain polygenic genetic disease has a gender difference, the incidence of relatives of sexually transmitted patients with low incidence is rather high.

Pediatric asthmatic bronchitis prevention

For children with asthmatic bronchitis, if there is suspicious bronchial asthma, asthma prevention and treatment measures should be given as soon as possible, and preventive methods for recurrent or chronic bronchitis:

1. General method

First, look for pathogens, actively treat chronic lesions or prevent potential factors to reduce the chance of acute attacks, then give reasonable feeding, add food supplements in time to enhance physical fitness, and strengthen physical exercise, more outdoor activities, if necessary, oral vitamin A, to increase Resistance of the respiratory mucosa.

2. Tracheitis vaccine

It can stimulate the body to produce immune response, increase phagocytic function, prevent bronchitis recurrence, usage: in the intermittent period, subcutaneous injection once a week, the first 0.1m1, if there is no adverse reaction, then increase 0.1ml per week, until Each time 0.5m1 is the maximum dose, 10 times is a course of treatment. It can be used for several courses of treatment, especially in the regular season, and the suspension period is suspended.

3. Nuclear cheese

It is a hydrolysate of nucleic acid and casein, which can enhance the body's resistance. Usage: 2 times per week, 2m1, 10 times for one course of treatment, and can continue to be used when effective.

Pediatric asthmatic bronchitis complications Complications, pneumonia, asthma

Generally, there is no complication, and it can develop into pneumonia. Some children develop asthma later.

Pediatric wheezing bronchitis symptoms Common symptoms, wheezing, cough, wheezing, high fever

Age

The age of onset is small, and it is more common in children aged 1 to 3 years old.

2. General performance

Often secondary to upper respiratory tract infections, the condition is mostly not heavy, there are low or moderate fever, only a small number of sick children have high fever, prolonged expiration time, accompanied by wheezing sound and coarse wet voice, wheezing without obvious seizures, After treatment, the above symptoms were significantly alleviated on days 5-7.

Examination of pediatric asthmatic bronchitis

White blood cell count can be increased, viral infection can be normal, other routine examinations are normal, eosinophils examination, serum IgE levels can be increased in some children, chest X-ray examination without obvious abnormalities, may have bronchitis changes.

Diagnosis and diagnosis of pediatric asthmatic bronchitis

diagnosis

Diagnostic criteria (scoring method)

The National Pediatric Asthma Conference in 1988 proposed a diagnostic criteria for the assessment of asthma in infants and young children (scoring method): the principle of scoring by the author of repeated ageing of <3 years old:

(1) Infants and young children suffering from bronchiolitis or wheezing-like bronchitis, repeated wheezing episodes 3 times were 3 points.

(2) There is a wheezing sound of 2 points in the lungs.

(3) A sudden onset of wheezing symptoms is 1 point.

(4) The child has a history of other allergies 1 point.

(5) First, the second-degree relatives have a history of eczema, dermatitis, or asthma, 1 point, the total score of >5 points to diagnose infant asthma, wheezing episode only 2 times or total score 4 points, the initial diagnosis is asthmatic Bronchitis, and continue to follow-up observation, mostly children within 3 years old, occur in upper and lower respiratory tract infections, respiratory syncytial virus, parainfluenza virus, influenza virus and other infections are often pathogenic, have fever, prolonged exhalation time With wheezing sounds and coarse wet voices, after treatment, the symptoms are obviously relieved in about 1 week, which is easier to diagnose.

Differential diagnosis

For children with asthmatic bronchitis, we should pay attention to the family and children's own history of allergies, eosinophils, serum IgE levels and other data, if there is suspicious bronchial asthma, asthma should be given as soon as possible.

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