Sinusitis and chronic cough in children

WAO-ARIA consensus on chronic cough - Part II: Phenotypes and mechanisms of abnormal cough presentation - Updates in COVID-19

BACKGROUND

Chronic cough can be triggered by respiratory and non-respiratory tract illnesses originating mainly from the upper and lower airways, and the GI tract (ie, reflux). Recent findings suggest it can also be a prominent feature in obstructive sleep apnea (OSA), laryngeal hyperresponsiveness, and COVID-19. The classification of chronic cough is constantly updated but lacks clear definition. Epidemiological data on the prevalence of chronic cough are informative but highly variable. The underlying mechanism of chronic cough is a neurogenic inflammation of the cough reflex which becomes hypersensitive, thus the term hypersensitive cough reflex (HCR). A current challenge is to decipher how various infectious and inflammatory airway diseases and esophageal reflux, among others, modulate HCR.

OBJECTIVES

The World Allergy Organization/Allergic Rhinitis and its Impact on Asthma (WAO/ARIA) Joint Committee on Chronic Cough reviewed the current literature on classification, epidemiology, presenting features, and mechanistic pathways of chronic cough in airway- and reflux-related cough phenotypes, OSA, and COVID-19. The interplay of cough reflex sensitivity with other pathogenic mechanisms inherent to airway and reflux-related inflammatory conditions was also analyzed.

OUTCOMES

Currently, it is difficult to clearly ascertain true prevalence rates in epidemiological studies of chronic cough phenotypes. This is likely due to lack of standardized objective measures needed for cough classification and frequent coexistence of multi-organ cough origins. Notwithstanding, we emphasize the important role of HCR as a mechanistic trigger in airway- and reflux-related cough phenotypes. Other concomitant mechanisms can also modulate HCR, including type2/Th1/Th2 inflammation, presence or absence of deep inspiration-bronchoprotective reflex (lower airways), tissue remodeling, and likely cough plasticity, among others.

Approach to chronic cough

Chronic cough does affect quality of life in children. Most of the times it is treated with over-the-counter cough syrups and antibiotics. The etiology of chronic cough is so diverse, that treatment needs to be directed to the specific etiology, rather than treating symptomatically. Grossly, chronic cough is classified as specific and non-specific cough. Allergic conditions, followed by tuberculosis are more commonly encountered etiologies in India. Baseline investigations to be performed are chest radiograph and peak flow metry. If specific cause of cough is not obvious, then therapeutic trial with β2 agonist, followed by peak flowmetry to evaluate reversibility of airway hypersensitivity, is useful to label the child asthmatic or non-asthmatic. Rampant uses of antibiotics need to be avoided for conditions like asthma. If tuberculosis is diagnosed or suspected, it is better to treat the child, rather than giving therapeutic trial. Over-the-counter cough syrups are as good as placebo, and should be avoided. Trial of anti asthma, anti allergic rhinitis and anti reflux therapies are avoided, unless the diagnosis is one of these conditions. If the child is distressed or the case seems to be complicated, it is best to refer the child to a tertiary care centre and keep a close follow up.

Chronic cough in children

Cough is probably the most common cause of seeking medical care in pediatric practice. Most acute cough is caused by infection and usually resolves within less than 4 weeks. If it lasts longer, it is considered chronic and deserves investigation to identify the underlying cause, which can be almost any of a wide variety of illnesses of the respiratory tract and certain extrathoracic conditions. This review provides an optimal approach for diagnosis through a skillful history taking, physical examination, and selection of appropriate tests.

Chest radiography in supporting the diagnosis of asthma in children with persistent cough

OBJECTIVE

To establish whether chest radiographic findings suggestive of lower airway obstruction (LAO) disease support the diagnosis of asthma in pediatric patients with persistent cough in an outpatient setting.

METHODS

180 patient charts were reviewed. The patients were children aged 1 to 18 years referred over a 3-year period to a pediatric pulmonary subspecialty clinic for evaluation of cough lasting ≥ 4 weeks. Chest radiographic images obtained after the initial evaluation of 90 patients diagnosed with cough-variant asthma and 90 patients diagnosed with persistent cough from nonasthma origins were compared with radiologic findings of a control group consisting of patients with a positive tuberculin skin test and no respiratory symptoms. Increased peribronchial markings/peribronchial cuffing and hyperinflation were considered radiographically suggestive findings of LAO disease.

RESULTS

Children diagnosed with cough-variant asthma at the initial evaluation had higher rates of chest radiographic findings suggestive of LAO disease (30.00%) than children with persistent cough from other causes (17.80%) or those with a positive tuberculin skin test and no respiratory symptoms (8.16%) (overall P value = 0.0063). They also had higher rates of spirometry abnormalities suggestive of an LAO defect. Children with chest radiographic findings suggestive of LAO disease were found to be younger than those with normal chest radiographic findings (5.0 ± 2.7 years vs 8.6 ± 4.7 years; P < 0.0001).

CONCLUSION

This study suggests that chest radiographic findings indicative of an LAO in correlation with the clinical presentation can support the diagnostic suspicion of asthma, especially in younger children unable to perform spirometry.