Chronic Cough in Children and Teens: A Simplified Approach to the Evaluation
ABSTRACT: A cough is considered chronic when it persists for greater than 4 to 8 weeks. Typically, chronic cough is a lingering manifestation of a viral upper respiratory tract infection; other, more serious causes—such as asthma, upper airway disorders, or gastroesophageal reflux—must also be considered. Look to the history for diagnostic clues and order a chest film, which may point to pneumonia, hyperinflation, atelectasis, or cardiac or pulmonary abnormality. Diagnostic methods will depend, in part, on the child’s age. For example, pulmonary function tests can be useful in diagnosing asthma if the child is able to cooperate. Consider ordering a barium swallow for a very young child whose cough may be the result of a vascular anomaly. A pH probe study can help you determine whether cough is secondary to gastroesophageal reflux. Treatment is directed at the underlying cause. Consider referral to a pediatric pulmonologist if cough persists and further work-up is required.
The patient is a 4-year-old boy who has been coughing persistently for the past 2 months. The mother reports that about the time the coughing began, the child had a “cold” with nasal congestion and fever. These symptoms resolved, but a cough ensued. The mother tried using over-the-counter medications, including cough suppressants, but the cough has not abated. It occurs during the day and at night. It is disrupting the child’s sleep, and the teachers at his day-care center are concerned that he may be infecting other children.
This scenario is familiar to all primary care clinicians, who are frequently faced with a child with chronic cough—and his or her tired and frustrated parents. A child with a persistent cough is a source of both concern and potential disruption for the parents, other family members, and playmates and classmates. Parents want to know why their child is coughing and want the coughing to cease.
How will you approach the child with a chronic cough? How do you efficiently mine the history for key diagnostic clues? What diagnostic tests are most appropriate? The answers to these questions are the focus of this review. In this update of our previously published article “How to Handle Chronic Cough in Kids: A Practical Approach to the Workup” (Consultant For Pediatricians, September 2003, pages 315-321), we present a simplified approach to the evaluation of the child with a chronic cough in the primary care office (Table).
WHAT IS CHRONIC COUGH?
Depending on which definition one uses from the medical literature, chronic cough in childhood is a cough that persists for at least 4 to 8 weeks.1-3 Every day in our pediatric clinic, we see children with cough that lingers after a viral upper respiratory tract infection (URI). The challenge is to determine whether the persistent cough is just a resolving symptom of the URI—or whether it is a manifestation of a serious condition that requires more aggressive therapy. In children without a preceding URI or obvious lower respiratory tract infection, other causes must be considered.
Many studies detail the causes of chronic cough in childhood.4-9 Bacterial lung infections usually produce acute respiratory symptoms that readily point to the diagnosis. However, some infectious agents can invade the pulmonary system and produce insidious or prolonged symptoms: these agents include respiratory syncytial virus, cytomegalovirus, Mycoplasma, Bordetella pertussis, Ureaplasma urealyticum, Chlamydia trachomatis, Mycobacterium tuberculosis, and rarely fungal infections.
The usual causes. Holinger and Sanders6 determined that the most common causes of chronic cough among patients in their otolaryngology clinic between 2 months and 15 years of age were (in descending order of occurrence):
•Asthma (cough variant).
Gastroesophageal reflux and vascular anomalies were the most common causes of chronic cough in children 18 months and younger.6 Asthma was a close third, followed by tracheomalacia, sinusitis, and subglottic stenosis. Other diagnoses included “viral” infection, bronchogenic cyst, cystic fibrosis, and foreign-body aspiration. Sinusitis was the most common cause of chronic cough among those aged 18 months to 6 years, followed by asthma, subglottic stenosis, and gastroesophageal reflux. The most common causes of chronic cough among children 6 to 16 years old were (in descending order) asthma, psychogenic cough, sinusitis, gastroesophageal reflux, and subglottic stenosis. Interestingly, even though asthma was the most common cause of cough in this age group, it was also the most erroneous diagnosis made by the referring clinician; this finding serves as a reminder that other causes need to be considered.
Palombini and colleagues7 described the multicausal pathogenesis of chronic cough in their teenage and adult patients and stressed the frequent association of asthma, postnasal drip, and gastroesophageal reflux. These 3 conditions—alone or in combination—accounted for 93.6% of the causes of chronic cough.
In a more recent study, Asilsoy and colleagues8 applied the evaluation method described in the 2006 recommendations of the American College of Chest Physicians (ACCP), which is briefly described below, to 108 children with chronic cough. The most common diagnoses were as follows: asthma, protracted bronchitis, upper airway cough syndrome, and gastroesophageal reflux disease. Upper airway cough syndrome refers to the presence of postnasal drip and nasal inflammation that responds to treatment with antihistamines, nasal corticosteroids, or nasal saline.8
Clues to uncommon causes. A study in India found that the most common causes of chronic cough in children between ages 1 and 12 years were (in descending order of frequency) asthma, tuberculosis, sinusitis, pertussis, gastroesophageal reflux, and infections other than tuberculosis.9 This study brings to light the role that some infectious agents play in causing chronic cough and underscores the importance of a detailed history of where a child lives or has traveled. Pertussis may cause persistent cough in a susceptible adolescent or adult who serves as the source of infection for the younger child.
Tuberculosis deserves special mention because of its impact worldwide. Children who are in contact with a high-risk adult are vulnerable to tuberculosis infection. High-risk adults are those born in countries in which tuberculosis is en-demic; residents of correctional facil-ities, shelters, or nursing homes; illicit drug users; persons infected with HIV; health care workers; and the homeless.10
Miscellaneous causes. Children who are exposed to first- or second-hand smoke, environmental air pollution, or allergens may also present with chronic cough.11 Congenital anatomic defects, cystic fibrosis, and primary ciliary dyskinesia (immotile cilia syndrome) can cause chronic cough; typically, other symptoms of these disorders are evident—such as failure to thrive, GI abnormalities, and recurrent infection. Rarely, a foreign body present in the ear canal can cause chronic cough.12 Suspect psychogenic cough when coughing sounds like an exaggerated honking noise and disappears during sleep. The younger the child the less likely the cough is psychogenic.
The importance of the history and physical. The clinical history offers clues to the cause of chronic cough. The 2006 ACCP evidence-based clinical practice guidelines include inquiry about the quality of the cough, specifically whether it is “wet” or “dry.”1 Exacerbation of cough with exercise or meals suggests asthma or gastroesophageal reflux disease respectively, while unrelenting URI symptoms suggest sinusitis. Past personal and family history of allergies, asthma, recurrent infections, failure to thrive, and smoke exposure needs to be detailed. A history of travel to foreign countries or contact with an adult with a chronic cough offers clues to the possibility of tuberculosis or pertussis.
A thorough examination—especially of the respiratory and GI tracts and the cardiovascular system—is indicated, and signs of pulmonary disease (eg, tachypnea, wheezing, or clubbing of the fingers) should be sought. Positive factors in the history and physical examination suggest the appropriate diagnostic path.
Watch, wait, and review. The 2006 ACCP guidelines provide a detailed algorithm on how to evaluate the patient younger than 15 years with chronic cough.1 The algorithm emphasizes a “watch, wait, and review” approach for the child without an obvious underlying diagnosis (or a “nonspecific cough”), which allows for eventual resolution of the cough. An alternate to the watch and wait route is to give empiric treatment with inhaled corticosteroids for a “dry cough” and antibiotics for a “wet cough.” When empiric trials of medications are prescribed, have a time limit for the length of treatment to look for improvement, such as 2 to 3 weeks. Any child with persistent productive cough requires aggressive evaluation for more serious underlying conditions, such as cystic fibrosis. Consider referral to a pediatric pulmonologist if further evaluation is necessary.
Imaging studies. We recommend obtaining a chest roentgenogram in all children with chronic cough. The goal is to detect any suggestion of a pulmonary, cardiac, or thoracic abnormality that may prompt further investigation—such as bronchoscopy or CT or MRI of the chest.
Chest films and CT scans. Often, the chest film is normal, but it may reveal a possible pneumonia (Figure), hyperinflation, atelectasis (as in a patient suffering from asthma or foreign-body aspiration), or other cardiac and pulmonary abnormalities (such as bronchiectasis, mediastinal adenopathies, or less frequently a congenital lung malformation). Keep in mind that not all foreign bodies are visualized on plain chest films. A CT scan should be obtained on a case-by-case basis, and perhaps after consultation with a pediatric pulmonologist, because of the increased exposure to radiation with use of this modality.
Sinus x-ray films and CT scans. The use of sinus radiographs is not addressed in the 2006 ACCP guidelines, and the use of CT scans of the sinuses is not routine.1 The American Academy of Pediatrics (AAP) recommends against imaging of the sinuses in children aged 6 years or younger as an aid in the diagnosis of acute bacterial sinusitis. The AAP recommends CT scanning for patients who are possible candidates for surgery.13
Pulmonary function tests. In children who are able to cooperate, spirometry aids in the diagnosis of asthma. It is possible to obtain consistent pulmonary function test results in children aged 5 years or younger, but this is not always feasible.14 The diagnosis of asthma in general can be suspected when there is a history of recurrent cough and wheezing that responds to bronchodilators, such as albuterol.
Barium swallow (esophagram or upper GI series). This test can provide additional information about the child’s anatomy; abnormal results may prompt further evaluation with CT or MRI of the chest.
Consider ordering a barium swallow especially for the child who has a chronic cough during the first few years of life. This test may suggest the presence of a congenital vascular anomaly (such as an aberrant innominate artery, or a vascular ring compressing onto the trachea), a major cause of chronic cough among young children.5
pH Probe. Consider a pH probe study to determine whether gastroesophageal reflux is the underlying problem. Referral to a pediatric gastroenterologist for this procedure may be warranted.
Miscellaneous tests. Consider testing for tuberculosis with a purified protein derivative test, performing a sweat chloride test, and ordering an evaluation for immunodeficiency disorders. Because laboratory confirmation of many uncommon infectious agents can be difficult, an infectious disease specialist consultation should be considered.
Referral to a pediatric pulmonologist is recommended when endoscopy (flexible bronchoscopy) is required for further evaluation. Endoscopy is particularly helpful in the young infant,6 but can be helpful in persons of all ages. The 2006 ACCP guidelines provide indications for flexible bronchoscopy. These include evaluation for possible airway disorders, abnormal radiographic findings, possible foreign-body inhalation or aspiration syndrome, and the need for lavage studies.1
An allergist/immunologist can aid in the evaluation for underlying allergies or immunodeficiency.
TREAT THE UNDERLYING CAUSE
Here we offer treatment suggestions for the most common causes of chronic cough. A discussion of treatment of various infections is beyond the scope of this article; the Red Book serves as an excellent source for up-to-date recommendations.15 On a case-by-case basis, empiric therapy is an option for the child with asthma or infection—especially when the clinical history is suggestive and optimal testing may not be available because of the patient’s age. The safety and cost-effectiveness of this approach have not been established for pediatric patients, as they have for adults,16,17 but a trial may be desirable in some children (eg, in an infant with a persistent cough after an uncomplicated URI). The 2006 ACCP guidelines emphasize that any treatment of chronic cough should be etiologically based.1
Asthma. This disease must be treated aggressively so that the child is symptom-free. If response to short-acting ß-agonists has been observed, these inhaled medications should be used for symptom relief. In addition, anti-inflammatory medications, such as inhaled corticosteroids—at the lowest effective dosages—are recommended for the treatment of all “persistent” grades of asthma, with the possible addition of leukotriene modifiers. However, if no response is observed with this intervention, a consult with a pulmonologist should be considered. Inhaled long-acting ß2-agonists may also be added in step-up therapy. The reader is referred to the most up-to-date treatment guidelines for childhood asthma.18 The clinician’s time is well-spent in educating the family about asthma and its treatment—and in reinforcing that education.
Upper airway disorders. The AAP recommends antibiotic therapy for pediatric patients with acute bacterial sinusitis but acknowledges that the optimal duration of therapy has not been determined. Chronic inflammation of the sinuses accompanied by symptoms that persist for at least 90 days may be caused by disorders such as gastroesophageal reflux, underlying allergic rhinitis, pollution exposure, and cystic fibrosis.13 As with chronic cough, the precise cause of the chronic sinus disease needs to be determined and treated. Certainly, many children suffer from asthma, allergies, and sinusitis simultaneously. In addition, recurrent/chronic sinusitis may be a manifestation of uncontrolled allergic rhinitis, both of which may perpetuate asthma symptoms, thus, all of these conditions need to be aggressively treated.
Gastroesophageal reflux. The many available treatment modalities—such as upright positioning, thickened feeding formula for very young children, H2 blockers, proton pump inhibitors, motility agents, and surgery—have been studied to varying degrees in children. The severity of the child’s symptoms dictates the extent of therapy.
Psychogenic cough. This phenomenon has been reported to be alleviated by wrapping a bedsheet tightly around the patient’s chest and convincing him that the bedsheet will aid the chest muscles in eliminating the cough.19 Bye20 reported that a peak flow meter provided positive feedback to an asthmatic child suffering from a psychogenic cough and helped eliminate that cough. Perhaps offering a non-asthmatic child concrete evidence of a normal peak flow may bring relief from psychogenic cough. In some cases, a behavioral medicine consultation may be required to stifle the psychogenic cough.
CONGENITAL ANOMALIES, FOREIGN BODIES
Congenital anomalies and other less common causes of chronic cough often require the expertise of a pediatric specialist (such as a pulmonologist, cardiologist, or surgeon) for definitive treatment. Whether they are needed to correct an anatomic abnormality, remove a foreign body, or offer further treatment options, the pediatric specialist needs to be involved. Patients with certain illnesses, such as cystic fibrosis, require a multidisciplinary approach.
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