xRead - Globus and Chronic Cough (April 2024)

Clinical Review & Education Review

Otolaryngologic Management of Chronic Cough in School-aged Children

ing cough and/or bronchospasm. 22 In more severe cases of GERD, the refluxate can reach the larynx, become microaspirated, and lead to tracheobronchitis and pneumonitis. Additionally, it is important to recognize that although esophagitis can manifest with only ex traesophageal symptoms such as cough in up to 32% of children, GERD can contribute to chronic cough even in the absence of esopha gitis (laryngopharyngeal reflux). 23 Diagnoses of GERD and laryngopharyngeal reflux can be made based on a detailed history and physical examination. However, for patients with GERD-related complications, further diagnostic test ing and referral to a gastroenterologist is indicated. A number of diagnostic testing options are available, including upper gastroin testinal series with barium contrast and fluoroscopic examination, esophageal pH monitoring, esophageal manometry, endoscopy with possible biopsies, and scintigraphy. However, recent consen sus recommendations do not recommend the routine use of these studies for the routine diagnosis of GERD unless anatomic abnor mality is suspected or specific alarm signs are present. 23 Airway Hyperreactivity Airway hyperreactivity is a key pathophysiologic feature of asthma and, along with chronic airway inflammation, can lead to chronic cough. 24 Cough is a frequent symptom in patients with asthma, par ticularly persistent nocturnal cough. 25 There are many different phe notypes under the broad category of asthma. For example, in pa tients with cough variant asthma, wheezing or dyspnea may be absent, and patients can have normal baseline spirometry but will demonstrate bronchial hyperreactivity on methacholine challenge. 26 It is postulated that patients with cough variant asthma likely have heightened cough receptor sensitivity to triggers such as allergen exposure, cold temperatures, exercise, and infection. 27,28 While asthma is one of the most common chronic illness in chil dren, it is likely overdiagnosed and overtreated. 29,30 Epidemio logic studies suggest that chronic cough in the absence of other symptoms, such as wheeze, chest tightness, and/or dyspnea, is un likely to be due to asthma, 31,32 a stance that is also emphasized in the 2006 American College of Chest Physicians evidence-based clini cal practice guidelines. 7 Given the complexities of establishing a de finitive diagnosis of airway hyperreactivity, when the diagnosis is sus pected, further evaluation by pulmonologists, often with chest radiographs, spirometry (when age appropriate), and response to bronchodilators, is indicated. Additional Causes Although far less common, other causes of cough may also be con sidered. Among these are aspiration, primary ciliary dyskinesia, and habit cough. Cough associated with aspiration often occurs when a child is eating or drinking and may be accompanied by a history of frequent or recurrent pneumonia. Instrumental assessment of swal lowing function is an essential component of the evaluation if aspi ration is suspected. Primary ciliary dyskinesia is another uncom mon cause of cough but should be suspected in children with frequent upper respiratory tract infections and recurrent acute oti tis media or in children with symptoms of cough and the presence of situs inversus. Diagnosis can be made either through ciliary bi opsy or genetic testing. Habit cough, also known as psychogenic cough, typically presents as a barking or honking cough with no de tectable organic, anatomic, or physiologic cause. A key feature of

and increased nasal secretions. These secretions can directly stimu late afferent fibers from the vagus nerve present in the posterior pha ryngeal wall and larynx to elicit cough. 12 In addition to mechanical stimulation, nasal secretions exert an inflammatory response within the pharynx, leading to further vagal stimulation and promotion of lymphoid hypertrophy. For these reasons, chronic cough is a fre quent symptom in children with rhinitis and rhinosinusitis, appear ing in up to 80% of patients. 13,14 Additionally, asthma is a frequent comorbidity in these patients and can often be exacerbated by poor control of nasal disease, thus emphasizing the importance of con sidering the entire airway. This concept, in which an inflammatory process at one level of the airway can simultaneously affect other levels, is referred to as the unified airway model. 12 Allergic rhinitis will affect approximately 10% to 30% of chil dren and can be diagnosed clinically based on the presence of aller gic symptoms and at least 1 additional symptom of nasal conges tion, rhinorrhea, itchy nose, and/or sneezing. 15 Allergy testing can be helpful for cases in which the diagnosis is uncertain, there is a treat ment failure, or identification of a specific causative agent is needed to tailor therapy. The first-line treatment for allergic rhinitis in both children and adults is intranasal steroids, which have been shown in randomized clinical trials to improve nasal symptoms and day time cough compared with placebo in adults and children older than 12years. 16 On average, children will experience 6 to 8 upper respiratory tract infections per year. The majority of these infections are viral in origin, and the associated cough will typically last less than 4 weeks. 17 Of these infections, 5% to 13% will be complicated by acute sinusitis. 18 When sinusitis symptoms have persisted for longer than 12 weeks, the patient is considered to have chronic rhinosinusitis. To definitively diagnose chronic rhinosinusitis, there must be 90 con secutive days with 2 or more subjective symptoms (nasal conges tion, nasal discharge, facial pressure/pain, or cough) and objective evidence of inflammation either on nasal endoscopy or computed tomography scan. 19 Overall, chronic rhinosinusitis will affect less than 2% of children. 19 However, for those who develop chronic rhino sinusitis, cough tends to be a predominant symptom, and the dis ease can have a substantial influence on quality of life for both pa tients and their caregivers, incur a high financial burden, and require many office and hospital visits to address symptoms. 19 Gastroesophageal Reflux/Laryngopharyngeal Reflux Gastroesophageal reflux is a physiologic event that occurs in 40% to 65% of healthy infants. 20 Reflux typically peaks around 1 to 4 months old and will spontaneously resolve around 12 months of age. 21 While reflux is a normal occurrence in infants, when it is as sociated with other symptoms, such as recurrent regurgitation, dys tonic neck posturing and back arching, cough, apnea, bradycardia episodes, and/or failure to thrive, it is considered pathologic GERD and requires further investigation and intervention. The association between cough and GERD is well described in the adult literature; however, it has not been commonly identified as a cause of pediatric cough. 4 Much of the difficulty in linking cough to GERD in children arises from the inherent difficult of proving cau sality and in the difficulty of diagnosing GERD in this population. The underlying mechanism leading to cough relies on irritation (physi cal and chemical) of vagal nerve fibers within the esophagus. The vagal stimulation then leads to a parasympathetic response produc

1060 JAMA Otolaryngology–Head & Neck Surgery November 2020 Volume 146, Number 11 (Reprinted)

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