The symptoms of cough last for >4 weeks are called chronic cough.

1. Age characteristics

When diagnosing chronic cough in children in clinical diagnosis, age factors should be fully considered. The common causes of chronic cough in children of different ages are shown in Table 2.

Table 2 Common causes of chronic cough in children of different ages

Age Causes

Infancy

Respiratory tract infection and post-infection cough, congenital trachea, lung development abnormality, gastroesophageal reflux, tuberculosis, other congenital cardiothoracic abnormalities

Early childhood

Respiratory infection and post-infection cough, upper airway cough syndrome, cough variant asthma, airway foreign body, gastroesophageal reflux, tuberculosis

Preschool

The same causes of early childhood, and there are also bronchodilation, etc.

School-age

Upper airway cough syndrome, cough variant asthma, post-infection cough, tuberculosis, cardiac cough, foreign body of the airway, bronchodilation, etc.

2. Specific cough

It refers to coughing with other symptoms or signs that can indicate specific causes, that is, cough is one of the symptoms of these well-diagnosed diseases. For example, coughing is accompanied by dyspnea, auscultation with expiratory dyspnea or wheezing, often suggests intrathoracic airway lesions such as tracheobronchiolitis, asthma, congenital abnormal airway development, etc.; accompanied by shortness of breath, hypoxia or cyanosis, lung inflammation; accompanied by growth and development disorders, clubbing fingers often indicate severe chronic lung diseases and congenital heart disease; accompanied by purulent sputum, lung inflammation, bronchodilation, etc.; accompanied by hemoptysis, severe lung infection, pulmonary vascular disease, lung hemosiderinosis or bronchodilation, etc.

3. Nonspecific cough

It refers to chronic cough that is the main or only manifestation and does not show abnormalities in chest X-rays. Currently, chronic cough in clinical practice mainly refers to this type of cough, also known as "chronic cough in a narrow sense". The causes of non-specific cough in children are of age characteristics, and require careful systematic evaluation, detailed medical history inquiries and physical examinations. Chest X-rays are required for this type of children, and those with appropriate age should undergo lung ventilation function examination.

1.

Respiratory tract infection and post-infection cough: Respiratory tract infection caused by many pathogenic microorganisms such as Bacillus pertussis, Bacillus tuberculosis, viruses, Mycobacteria pneumonia, and Chlamydia are common causes of chronic cough in children, and are more common in

Acute respiratory infection, cough after cough lasts for more than 4 weeks, may be considered after infection. The mechanism may be that the integrity of the airway epithelium caused by the infection and the squamous cattle of ciliated columnar epithelial cells and persistent airway inflammation accompanied by temporary airway hyperresponsiveness. The clinical characteristics and diagnostic clues of post-infection cough include: a clear recent history of respiratory infection; a irritating dry cough or a small amount of white sticky sputum; no abnormalities in the chest x-ray examination; normal lung ventilation function; cough is usually self-limiting; other causes of chronic cough. If the cough lasts for more than 8 weeks, other diagnoses should be considered.

2.

Cough variant asthma: CVA is one of the common causes of chronic cough in children, especially preschool and school-age children.

3.

Lower airway cough syndrome: various upper airway diseases such as rhinitis, sinusitis, chronic pharyngitis, chronic tonsillitis, nasal polyps, adenoid hypertrophy and other upper airway diseases can cause chronic cough. They were previously diagnosed as postnasal drip syndrome, which means cough caused by nasal secretions flowing backwards to the pharynx through the posterior nasal hole. ACPP recommends the name upper airway cough syndrome to replace PNDs.

The clinical characteristics and diagnostic clues of UACS include: chronic cough with or without sputum, cough is worse in the early morning or when the position changes, often accompanied by nasal congestion, runny nose, dry throat and foreign body sensation, repeated clearing of the throat, mucus adhesion of the posterior wall of the pharyngeal wall, a few children complain of headache, dizziness, low fever, etc.; tenderness may be found in the sinus area, yellow and white secretions may flow out at the opening of the sinus, follicles of the posterior wall of the pharyngeal wall are obviously hyperplasia, pebbles, and sometimes mucus adhesion of the posterior wall of the pharyngeal wall can be seen; targeted treatments such as antihistamines and leukotriene receptor antagonists, glucocorticoids for nasal use are effective; for sinusitis, corresponding changes can be seen in the sinus x-ray flat film or CT tablet.

4.

Gastroesophageal reflux cough: Gastroesophageal reflux is a physiological phenomenon in infancy. The incidence of GER in healthy infants is 40% to 65%, reaching a peak of 1 to 4 months, and it is often relieved naturally at the age of 1. When symptoms and gastroesophageal dysfunction are accompanied by gastroesophageal dysfunction, it becomes a disease, namely gastroesophageal reflux disease. The prevalence of GER in children is about 15%. The latest study found that only 4 of the 49 children with chronic cough were GER, while Zhao Shunying and others showed that only 1 of the 50 chronic coughs was GER, so there is currently no definite evidence that GER is a common cause of chronic cough in children in my country.

The clinical characteristics and diagnostic clues of GERC include: paroxysmal cough, sometimes severe cough, which often occurs at night; the symptoms mostly occur after diet and are difficult to feed. Some children are accompanied by discomfort in the upper abdomen or underxiphay, burning sensation behind the sternum, chest pain, sore throat, etc. In addition to causing cough, babies can also cause suffocation, bradycardia and arched back; it can lead to stagnation or delay in the growth and development of the children.

5.

Eosinophilic bronchitis: EB was first reported by Gibso in 1989. A recent prospective study revealed that EB accounts for 13.5% of adult chronic cough patients. EB is considered to be one of the important causes of chronic cough in adults, but its incidence in children is still unclear.

The clinical characteristics and diagnostic clues of EB include: chronic irritating cough; normal chest X-rays; normal lung ventilation function and no high airway response; relative percentage of eosinophils in sputum >3%; oral or inhaled glucocorticoid treatment is effective.

6.

Congenital respiratory diseases: mainly occur in infants and young children, especially in younger than 1 year old. They include congenital tracheoesophageal fistula, congenital vascular malformation compressing the airway, laryngeal tracheal bronchial softening and stenosis, bronchial pulmonary cysts, ciliary movement disorders, mediastinal tumors, etc. Gormley study reported that 75% of children with tracheal softening manifests as persistent cough, and its mechanism may be related to tracheal softening hinders the discharge of secretions and inflammatory damage to the peripheral bronchial. This condition is often misdiagnosed asthma.

7.

Psychogenic cough: ACCP recommends that children with chordal cough can only be diagnosed if tic diseases are excluded, and the cough is improved after behavioral intervention or psychological treatment; cough characteristics can only have a prompt effect on chordal cough and have no diagnostic effect.

The clinical characteristics and diagnostic clues of psychogenic cough include: it is common in older children; it is mainly about daily coughing, focusing on something or the cough disappears during night rest; it is often accompanied by anxiety symptoms; it is not accompanied by organic diseases, and other causes of chronic cough are excluded.

8.

Other causes: Foreign body inhalation: Cough is the most common symptom after airway foreign body is inhaled. Foreign body inhalation is an important cause of chronic cough in children, especially children aged 1-3. Studies have found that 70% of patients with airway foreign body inhalation are coughing, and other symptoms include reduced breathing sound, wheezing, suffocation history, etc. Cough is usually manifested as paroxysmal and violent choking, and can only manifest as chronic cough with obstructive emphysema or atelectasis. Once foreign bodies enter the area below the small bronchus, there can be no cough, which is the so-called entry into the "silent area".

Drug-induced cough: Children rarely use angiotensin-converting enzyme inhibitors. Some children with renal hypertension will induce cough after using ACEI such as captopril. The mechanism may be related to bradykinin, prostaglandin, substance P secretion, etc. ACEI-induced cough is usually manifested as chronic persistent dry cough, which is aggravated at night or in lie down. Discontinuation of medication for 3 to 7 days can significantly reduce the cough or even disappear. B adrenaline receptor blockers such as propeptyl alcohol can cause high responsiveness of the bronchials, so it may also lead to drug-induced cough.

Ear-derived cough: 2%-4% of the population have vagus nerve ear branches. In this group, when the middle ear is lesions, the vagus nerve will be stimulated to cause chronic cough. Ear-derived cough is a rare cause of chronic cough in children.

1. Diagnostic means

1.

Medical history and physical examination: Ask for the medical history in detail and find out the causes of chronic cough as much as possible, including physical, chemical, biological causes, etc., which plays an important role in the diagnosis of the cause. Pay attention to the nature of the cough, such as barking like dogs, geese whispers, intermittent or paroxysmal, and pay attention to the aggravation factors and accompanying symptoms of the cough. Those with chronic cough with sputum should pay attention to whether there is bronchodilation and underlying underlying diseases such as cystic fibrosis and immunodeficiency diseases. Physical examination of the lungs and heart, whether there is cyanosis of the nail bed, clubbing, etc. Pay attention to assessing the growth and development of the child, respiratory rate, and whether there is a deformity in the chest.

2.

Auxiliary inspection:

Radiological examination: Children with chronic cough should have routine chest X-rays, and the next diagnostic treatment or examination should be determined based on whether the chest X-ray is normal or not. When sinusitis is suspected, Cava's position is taken or it is recommended to go to the otolaryngology department for further diagnosis and treatment. Chest CT helps to detect small and medium-sized lesions in the mediastinum, hilar lymph nodes and lung fields, and high-resolution CT helps diagnose atypical bronchodilation, interstitial lung diseases, etc. CT sinus slices show that nasal mucosa thickens >4mm or flat or blurred or opaque in the sinus cavity are characteristic changes of sinusitis. Sinus CT and MRI examination are one of the indispensable diagnostic methods, but they should not be listed as routine examinations, and the doctor can decide to implement them according to the condition. The explanation of the results should also be cautious in children, especially children under 1 year old, because the sinus development in children is not perfect and the structure is unclear. Imaging alone can easily cause excessive diagnosis of "sinusitis".

Lung function: Children over 5 years old should undergo routine lung ventilation function examination. If necessary, bronchodilation test or bronchial excitation test can be further performed based on the forceful exhalation volume of one second to assist in the diagnosis of asthma and the identification of EB.

Bronchoscopy: Bronchoscopy can be performed when suspected of chronic cough caused by airway development deformities, foreign bodies, etc., and pathogenic microorganisms that require anti-contamination.

Inducing sputum or bronchial alveolar lavage fluid cytology and isolation and culture of pathogenic microorganisms: it can clarify or suggest respiratory infection pathogens. If eosinophils are elevated, it is the main indicator for diagnosing allergic inflammation such as EB.

Others: PPD skin test, serum total IgE and specific IgE measurement, skin prick test, 24-hour esophageal pH monitoring, esophageal cavity impedance detection, etc. The diagnostic value of exhaled nitric oxide measurement, tracheal bronchial biopsy, cough receptor sensitivity detection, etc. in children's chronic cough is still uncertain.

2. Diagnostic procedures

Pediatricians should be aware that chronic cough is just a symptom, and clinically they should be as clear as possible about the cause of chronic cough. The diagnostic procedures should range from simple to complex, from common diseases to rare diseases. Diagnostic treatment helps diagnose chronic cough in children. The principle is to conduct diagnostic treatment in the order of UACS, CVA, and GERC when there is no clear cause prompt. See Figure 1 for details of the diagnostic process.

Meet the diagnostic criteria for chronic cough in children

Evaluation inquiry about medical history and physical examination

Chest X-ray pulmonary ventilation function examination

Selective check

Sinus X-ray, 24-hour esophageal pH monitoring, bronchoscopy, CT, serum IgE and specific IgE, skin prick test, inducible sputum examination, etc.

Clarify diagnosis and treatment

There are clues to the cause

Differential diagnosis of specific cough

Bronchial excitation test

Diagnostic treatment: according to the order of upper airway cough syndrome, cough variant asthma, gastroesophageal reflux cough

Cough variant asthma

The principle of treating chronic cough in children is to clarify the cause and treat the cause. If the cause is unknown, empirical symptomatic treatment can be carried out in order to achieve effectiveness.

Control; if the cough symptoms do not relieve after treatment, they should be re-evaluated. Antipnea drugs should not be used in infants. ACCP recommends diagnosis of non-specific chronic cough in children

During the treatment process, the expectations of the parents of the child should be paid attention to and paid attention, emphasizing the importance of follow-up and re-evaluation after treatment, namely: observation, waiting and follow-up.
Chapter completed!