Cough is one of the most common symptoms of respiratory diseases in children. The clinical causes of cough are complex, especially in children with chronic cough, which is difficult to diagnose, and prolonged treatment affects the physical and mental health of the child and his or her school life, and imposes an additional economic burden on parents and society.
In the past 20 years, systematic studies on the causes and treatment of cough in adults have been conducted in Europe and the United States, and guidelines for the diagnosis and treatment of cough have been developed.
Evidence from evidence-based medicine suggests that the etiology of chronic cough in children is different from that of adults, and the causes of chronic cough in children of different ages also vary, so the diagnosis and treatment of cough in children should not follow adult guidelines, but should have guidelines for the diagnosis and treatment of chronic cough that meet the characteristics of children. In this regard, guidelines for the diagnosis and treatment of chronic cough in children have been developed in the United States, Europe, Singapore, Australia, and Japan. In recent years, there have been discussions, reviews and clinical reports on this topic in domestic pediatric journals, but in general, it is still in its infancy, and there is a lack of multicenter prospective epidemiological investigations on the etiology and unified criteria for the diagnosis and treatment of chronic cough.
This guideline was developed mainly with reference to the 2006 American College of Chest Physicians (ACCP) Clinical Evidence-Based Practice Guidelines for Chronic Cough in Children, and also incorporates relevant clinical experience in China as far as possible, with the aim of standardizing and guiding pediatricians in the diagnosis and treatment of chronic cough.
The first draft of the guidelines was widely consulted by pediatric respiratory experts and clinical pediatricians at the Symposium on Chronic Cough and Recurrent Respiratory Tract Infections in Children held in Yangzhou, Jiangsu Province in September 2007; the second draft of the guidelines was again reviewed by more than 10 experts from the Respiratory Group of the Pediatric Branch of the Chinese Medical Association. On this basis, the editorial board of the Chinese Journal of Pediatrics held another final draft meeting to determine the relevant contents of this guideline: including the level of evidence-based medical evidence and recommendation level for the diagnosis and treatment of chronic cough in children, the definition of chronic cough in children, its etiology, diagnosis and its procedures and treatment.
I. Age characteristics
1. Age should be fully considered in the clinical diagnosis of chronic cough in children
2. Congenital respiratory disorders: mainly seen in infants and children, especially within 1 year of age. The Gormley study reported that 75% of children with tracheoesophageal cartilage (second only to congenital vascular malformation) had persistent cough, and the mechanism may be related to tracheal cartilage obstructing the discharge of secretions and inflammatory damage to the terminal bronchi. The mechanism may be related to the obstruction of secretion drainage by softened airways and inflammatory damage to the terminal bronchi. This condition is often misdiagnosed as asthma.
3. psychogenic cough: ACCP recommends that psychogenic cough in children should be diagnosed only if tic disorders are excluded and the cough improves after behavioral interventions or psychotherapy; cough features are only suggestive of psychogenic cough, not diagnostic [E/B].
4. The clinical features and diagnostic clues of psychogenic cough are: (1) it is more common in older children; (2) the cough is predominantly daytime and disappears when focusing on an event or resting at night; (3) it is often accompanied by anxiety symptoms; and (4) it is not accompanied by organic disease and other causes of chronic cough are excluded.
5. Other etiologies.
(1) Foreign body aspiration (foreign bodya spiration): cough is the most common symptom after aspiration of foreign bodies in the airway, and foreign body aspiration is an important cause of chronic cough in children, especially those 1-3 years old. Studies have found that 70% of patients with foreign body aspiration present with cough, and other symptoms include decreased breath sounds, wheezing, and a history of asphyxia. Once the foreign body enters the area below the small bronchus, there can be no cough, i.e. the so-called “silent zone”.
(2) Drug-induced cough: Angiotensin-converting enzyme inhibitors (ACEl) are less commonly used in children, and some children with renal hypertension may have cough induced by the use of ACEIs such as captopril. The mechanism may be related to the secretion of bradykinin, prostaglandins, and substance P. ACEI-induced cough usually manifests as a chronic persistent dry cough, which is aggravated at night or when lying down, and can be significantly reduced or even disappeared by discontinuing the drug for 3-7 d. B-adrenergic receptor blockers such as tretinoin can cause bronchial hyperresponsiveness, so they may also lead to drug-induced cough.
(3) Otogenic cough: 2%-4% of the population has the vagus nerve branch (arnold nerve). In this group, when the middle ear is diseased, the vagus nerve is stimulated and causes a chronic cough. Otogenic cough is a rare cause of chronic cough in children.
[Diagnosis of chronic cough in children and its process]
I. Diagnostic tools
1. History and physical examination: Take a detailed medical history to find out the cause of chronic cough including physical, chemical and biological causes as much as possible, which is important for etiological diagnosis. Pay attention to the nature of the cough, such as barking, goose, intermittent or paroxysmal, and the aggravating factors of the cough and its accompanying symptoms. In chronic cough with sputum, attention should be paid to the presence of bronchiectasis and underlying diseases such as cystic fibrosis and immunodeficiency disease. Physical examination of the lungs and heart, presence of nail bed cyanosis, pestle fingers, etc. Attention should be paid to the assessment of the child’s growth and development, respiratory rate, and the presence of thoracic deformities.
2.Auxiliary examinations.
(1) Radiological examination: Children with chronic cough should be routinely examined with chest X-ray, and the next diagnostic treatment or examination should be decided based on whether the chest X-ray is normal or not. A cavitation is taken when sinusitis is suspected or further consultation in otorhinolaryngology is recommended. CT of the chest helps to detect small and medium-sized lesions in the mediastinum, hilar lymph nodes and lung fields, while high-resolution CT helps to diagnose atypical bronchiectasis, interstitial lung disease, etc. CT sinus films showing thickening of the nasal mucosa >4 mm or air-fluid flat or fuzzy opacity in the sinus cavity are characteristic changes of sinusitis. CT and MRI of the sinus region is one of the indispensable diagnostic tools, but it should not be included as a routine test and can be performed at the discretion of the doctor depending on the condition. The interpretation of the results also needs to be cautious in children, especially in children under 1 year old, because the sinuses are not well developed (maxillary sinus and septal sinus are present at birth but small, frontal sinus and pterygoid sinus appear only at 5-6 years old) and the structure is not clear, so the diagnosis of “sinusitis” can easily be overdiagnosed by imaging alone.
(2) Pulmonary function: Children over 5 years of age should routinely undergo pulmonary ventilation function tests and, if necessary, further bronchodilatation tests or bronchial excitation tests based on the force expiratory volume in one second (FEVl) to aid in the diagnosis of asthma (including CVA) and the differentiation from EB.
(3) Bronchoscopy (fiberoptic bronchoscopy, rigid bronchoscopy, etc.): bronchoscopy is feasible for chronic cough caused by suspected airway developmental malformations, foreign bodies (including airway endogenous foreign bodies and sputum plugs), and when anti-pollution pathogenic microbial examination is required.
(4) Induced sputum or bronchoalveolar lavage fluid cytology and isolated culture of pathogenic microorganisms: can clarify or suggest respiratory tract infection pathogens, and if eosinophils are elevated is the main indicator for diagnosis of allergic inflammatory diseases such as EB.
(5) Others: PPD skin test, serum total IgE and specific IgE assay, skin prick test (SPT), 24-hour esophageal pH monitoring, esophageal luminal impedance test, etc. In contrast, the diagnostic value of exhaled breath nitric oxide assay, tracheobronchial biopsy, and cough receptor sensitivity testing for chronic cough in children is uncertain.
II. Diagnostic procedures
Pediatricians 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 in clinical practice. The diagnostic procedure should range from simple to complex and from common to rare diseases. Diagnostic treatment contributes to the diagnosis of chronic cough in children and is based on the principles of UACS, CVA, and GERC sequence in the absence of a clear indication of the cause. The diagnostic process is detailed in Figure 1.
[Treatment]
The principle of management of chronic cough in children is to identify the cause and treat it for that cause. If the etiology is unknown, empirical symptomatic treatment may be administered with a view to achieving effective control; if the cough symptoms do not resolve after treatment, it should be re-evaluated. ACCP recommends that the expectations of parents should be taken into account in the management of non-specific chronic cough in children and emphasizes the importance of post-treatment follow-up and re-evaluation, i.e., watch, wait and review.
I. Drug therapy
1. Expectorant drugs: If chronic cough is accompanied by sputum, the principle of expectorant should be adopted, and the cough should not be stopped simply to avoid aggravating or causing airway obstruction, and N-acetylcysteine, aminoglycerol hydrochloride, guaiacol glycerol ether, myrtle oil and herbal expectorants can be used.
2, antihistamines: H1 receptor antagonists such as chlorpheniramine, loratadine, cetirizine, etc. can be used to treat UACS.
3, antibacterial drugs: antibacterial drugs can be considered for chronic cough with clear bacterial or Mycoplasma pneumoniae or Chlamydia pathogenic infections. Macrolide antibiotics, including erythromycin, azithromycin, and clarithromycin, may be chosen for Mycoplasma pneumoniae or Chlamydia infections. After initial experience with other pathogenic infections, if antibiotics need to be adjusted, they should be selected according to the results of drug sensitivity tests.
4. Asthma and anti-inflammatory drugs: including glucocorticoids, β2 agonists, M-blockers, leukotriene receptor antagonists, theophylline and other drugs. Mainly used for the targeted treatment of CVA, EB, allergic rhinitis, etc. Glucocorticoid therapy should be re-evaluated after 2 to 4 weeks . Post-infection cough can generally be relieved by itself, and short-term use of inhaled or oral glucocorticoids, leukotriene receptor antagonists or M receptor blockers can be considered for those with severe symptoms.
5. Digestive system drugs: H2 receptor antagonists such as cimetidine and pro-gastric motility drugs such as domperidone are advocated. Lack of experience in the use of proton pump inhibitors in children.
6. Cough suppressants: The use of cough suppressants is not advocated for chronic cough especially before the etiology is clear, and the use of such drugs is associated with morbidity and mortality of some diseases. The American Academy of Pediatrics warns that codeine is prohibited for the treatment of all types of cough. The sedative effect of promethazine (finasteride) has the potential to mislead parents to apply the drug to reduce their child’s fussiness while ignoring the adverse effects of the drug, including irritability, hallucinations, abnormal muscle tone, and even apnea and sudden infant death. Adverse reactions are evident in infants, leading the WHO to warn that promethazine is contraindicated in children under 2 years of age and is prohibited as a cough suppressant, and the Cochrane Review of Symptomatic Drugs for Pertussis also noted no significant benefit from the use of diphenhydramine.
II. Non-pharmacological treatment
Take care to remove or avoid factors that trigger or aggravate cough.
1. Avoid exposure to allergens, exposure to cold, and smoky environments.
2. nasal irrigation, optional decongestants for sinusitis.
3.Changes in body position, changes in food properties, small and frequent meals, etc. are effective for GERC.
4, for foreign bodies in the airway should be promptly removed foreign bodies.
5. the best treatment for drug-induced, cough is to stop the drug.
6. psychotherapy can be given for psychogenic cough.
7. Timely vaccination to prevent respiratory infections and respiratory tract infections.