Diagnostic and differential diagnostic procedures for chronic cough in children Diagnostic methods History: Ask for a detailed history including the child’s age, duration of cough, nature of cough (e.g., barking, goose cough, intermittent or paroxysmal, dry or sputum cough, coughing at night or aggravated by exercise, etc.), presence of snoring, history of foreign body or suspected foreign body aspiration, history of medication, especially prolonged use of angiotensin-converting enzyme inhibitors, history of wheezing, history of allergic diseases or positive family history of allergic diseases, etc. The child should be exposed to environmental factors (e.g. passive smoking, environmental pollution, air pollution, etc.). Physical examination: Pay attention to the assessment of the child’s growth and development, respiratory rate, the presence of thoracic deformities, the presence of hypertrophy/enlargement of the palatine tonsils and/or proliferators, the presence of follicular hyperplasia in the posterior pharyngeal wall, the presence of adhesive secretions, the presence of cyanosis, pestle finger, etc. Pay particular attention to the examination of the lungs and heart. Ancillary examinations: (1) Imaging: Children with chronic cough should routinely have chest x-ray examinations to determine the next diagnostic treatment or examination based on the presence or absence of abnormalities on the chest x-ray. If the diagnosis is still not clear on chest x-ray or if the condition is complicated, a chest CT examination can be performed to clarify the diagnosis. For children with suspected adenoids or tonsillar hypertrophy or chronic tonsillitis, fiberoptic nasopharyngoscopy may be performed. CT films of the sinuses that show mucosal thickening of more than 4 mm, or air-fluid planes in the sinus cavity, or blurred opacities, are characteristic of sinusitis. Considering the possible damage of radiation to children, CT of the sinuses should not be included as a routine examination, and the interpretation of its results should be cautious especially in children under 1 year of age, because the sinuses of children are not yet well developed (maxillary and septal sinuses are present at birth but small, frontal sinuses and pterygoid sinuses are not present until 5-6 years of age), and the bone structure is not clear, so the imaging alone can easily cause “sinusitis The diagnosis of “sinusitis” is too much. Pulmonary function: Pulmonary ventilation function tests should be routinely performed in children over 5 years of age, and further bronchodilatation tests or bronchial excitation tests can be performed based on the first second of forceful expiratory volume to aid in the diagnosis and differential diagnosis of CVA, NAEB and AC. Fiberoptic rhinolaryngoscopy: For children with suspected rhinitis, sinusitis, nasal polyps, and adenoid hypertrophy/ enlargement, fiberoptic rhinolaryngoscopy can be performed to clarify the diagnosis. Bronchoscopy: Bronchoscopy and lavage can be done for chronic cough caused by suspected airway developmental malformations, airway foreign bodies (including airway endogenous foreign bodies and sputum plugs), etc. Induced sputum or bronchoalveolar lavage fluid cytology and pathogenic microorganism isolation and culture can clarify or suggest respiratory tract infection etiology, and the diagnosis of NAEB can also be clarified based on eosinophil percentage. Total serum IgE, specific IgE and skin prick test: they are useful for suspicion of allergy-related chronic cough and for understanding whether the child has atopic constitution. Hourly lower esophageal pH monitoring: is the gold standard for confirming the diagnosis of GERC. This test should be performed in children with suspected GERC. Exhaled breath NO (eNO) measurement: Elevated eNO is associated with eosinophil-associated airway inflammation. Measurement of eNO can be used as a non-invasive test to assist in the diagnosis of CVA and EB. Cough receptor sensitivity testing: This test is feasible when AC is suspected, and experience with this technique in children is still being developed. Diagnosis and differentiation: The diagnostic process should be conscious of the fact that chronic cough is only a symptom and that the cause of chronic cough should be clarified as much as possible. The diagnostic procedure should range from simple to complex, from common to rare diseases. Attention should be paid to age as a hint to the possible etiology of chronic cough in children, and the prevalence of each etiology causing cough within 24 h should be noted. Diagnostic treatment is helpful in the diagnosis of chronic cough in children and is based on the principle of diagnostic treatment in the order of CVA, UACS and PIC in the absence of clear etiologic hints. Treatment of chronic cough in children: The principle of management of chronic cough in children is to define the etiology and treat it for the cause. If the cause is unknown, empirical symptomatic treatment can be administered; if the cough does not resolve after treatment, it should be re-evaluated. The ACCP viewpoint and the results of the Composition Ratio Study suggest that the expectations of parents should be taken into account in the diagnosis and treatment of chronic cough, emphasizing the importance of post-treatment follow-up and re-evaluation, i.e., watch (The importance of post-treatment follow-up and re-evaluation was emphasized, namely: watch, wait and review. In children with chronic cough, attention should be paid to removing or avoiding exposure to allergens, smoke, and other environmental triggers and aggravators of cough. The principles of treatment for common causes of chronic cough in children are as follows: (a) UACS treatment is based on different diseases of the upper airway that cause chronic cough in children: Allergic (allergic) rhinitis: treatment with antihistamines, nasal spray glucocorticoids, or a combination of nasal mucosal decongestants and leukotriene receptor antagonists. Sinusitis: Treatment with antibacterial drugs, such as amoxicillin or amoxicillin + potassium clavulanate or azithromycin orally for at least 2 weeks, oral antihistamines for one week, nasal hormones for 4 weeks, supplemented by nasal irrigation, topical nasal decongestants [E/B] or expectorant drugs. Adenoid hypertrophy and/or chronic tonsillitis: according to the degree of adenoid hypertrophy, mild to moderate cases can be treated with nasal spray of glucocorticoids combined with leukotriene receptor antagonists and antihistamine agents for 1 to 3 months and wait for observation, and surgery can be taken if it is not effective. (B) CVA treatment can be given oral B2 receptor agonists (such as procaterol, terbutaline, salbutamol, etc.) as diagnostic treatment for 1 to 2 weeks, and transdermal absorbable B2 receptor agonists (tolterol) are also used, and cough symptom relief is helpful for diagnosis. Once a definite diagnosis of CVA is made, long-term standardized treatment of asthma is followed, with the choice of inhaled glucocorticoids or oral leukotriene receptor antagonists or a combination of both for at least 8 weeks. (c) PIC treatment is usually self-limiting, and treatment with oral leukotriene receptor antagonists or inhaled glucocorticoids may be considered for those with severe symptoms. (d) GERC treatment advocates the use of the H2 receptor antagonist cimetidine and the pro-gastric motility drug domperidone, and proton pump inhibitors can also be used in older children. Changing the position to semi-recumbent or prone with a 30-degree forward tilt, changing the nature of food, and having small and frequent meals are effective for GERC. (v) NAEB treatment bronchodilator treatment is ineffective, inhalation or oral glucocorticoid treatment is effective. (vi) AC treatment Advocate the use of antihistamines and glucocorticoids for treatment. (vii) Drug-induced cough The best treatment is to discontinue the drug for observation. (viii) Heart-induced cough Nasal irrigation, choice of nasal local decongestants or expectorant medication. (ix) Treatment of PBB Give oral 5 syringes of antibacterial drugs, preferably 7:1 amoxicillin a clavulanic acid preparation or 2nd generation or higher cephalosporins or azithromycin, etc. The course of treatment usually takes 2 to 4 weeks.