How to Handle Chronic Cough in Kids: A Practical Approach to the Workup

The patient is a 4-year-old boy who hasbeen coughing persistently for the past 2months. The mother reports that aboutthe time the coughing began, the childhad a "cold" with nasal congestion andfever. These symptoms resolved, but acough ensued. The mother tried usingover-the-counter medications, includingcough suppressants, but the cough hasnot abated. It occurs during the day andat night. It is disrupting the child's sleep,and the teachers at his day-care centerare concerned that he may be infectingother children.This scenario is all too familiar toprimary care clinicians who are facedwith a child with chronic cough--andhis or her tired and frustrated parents.A child with a persistent cough is asource of both concern and potentialdisruption for the parents, other familymembers, and playmates and classmates.Parents want to know why theirchild is coughing and want the coughingto cease.How will you approach the childwith a chronic cough? How do you efficientlymine the history for key diagnosticclues? What diagnostic tests aremost appropriate? The answers tothese questions are the focus of this review.We present an algorithm that offersa practical approach to the diagnosticworkup.WHAT ISCHRONIC COUGH?
A cough that persists for at least 3weeks (and usually 6 weeks or longer)is considered chronic.¹ Every day inour pediatric clinic, we see childrenwith cough that lingers after a viralupper respiratory tract infection (URI).The challenge is to determine whetherthe persistent cough is just a resolvingsymptom of the URI--or whether it isa manifestation of a serious conditionthat requires more aggressive therapy.In children without a preceding URI orobvious lower respiratory tract infection,other causes must be considered.Key diagnostic possibilities includeasthma, sinusitis, and gastroesophagealreflux, which are the most commonlyreported causes of persistentcough. Allergic rhinitis often goeshand in hand with asthma and sinusitisand contributes to exacerbations ofboth these conditions.WHAT CAUSE?
Many studies detail the causes ofchronic cough in childhood.^2-6 Bacteriallung infections usually produceacute respiratory symptoms that readilypoint to the diagnosis. However,some infectious agents can invade thepulmonary system and produce insidiousor prolonged symptoms: theseagents include respiratory syncytialvirus, cytomegalovirus, Mycoplasma,Bordetella pertussis, Ureaplasma urealyticum,Chlamydia trachomatis, andMycobacterium tuberculosis.The usual causes. Holinger andSanders4 determined that the mostcommon causes of chronic coughamong patients in their otolaryngologyclinic between 2 months and 15 yearsof age were (in descending order ofoccurrence):

• Cough variant asthma.
• Sinusitis.
• Gastroesophageal reflux.

Gastroesophageal reflux and vascularanomalies were the most commoncauses of chronic cough in children18 months and younger.

⁴

Asthmawas a close third, followed by tracheomalacia,sinusitis, and subglottic stenosis.Other diagnoses included "viral"infection, bronchogenic cyst, cystic fibrosis,and foreign-body aspiration. Sinusitiswas the most common cause ofchronic cough among those aged 18months to 6 years, followed by asthma,subglottic stenosis, and gastroesophagealreflux. The most common causesof chronic cough among children 6to 16 years old were (in descendingorder) asthma, psychogenic cough, sinusitis,gastroesophageal reflux, andsubglottic stenosis. Interestingly, eventhough asthma was the most commoncause of cough in this age group, itwas also the most erroneous diagnosismade by the referring clinician; thisfinding serves as a reminder that othercauses need to be considered.Palombini and colleagues

⁵

describedthe multicausal pathogenesisof chronic cough in their teenage andadult patients and stressed the frequentassociation of asthma, postnasaldrip, and gastroesophageal reflux.These 3 conditions--alone or in combination--accounted for 93.6% of thecauses of chronic cough.

Clues to uncommon causes.

Astudy in India found that the mostcommon causes of chronic cough inchildren between ages 1 and 12 yearswere (in descending order of frequency)asthma, tuberculosis, sinusitis, pertussis,gastroesophageal reflux, andinfections other than tuberculosis.6This study brings to light the role thatsome infectious agents play in causingchronic cough and underscores theimportance of a detailed history ofwhere a child lives or has traveled.Pertussis may cause persistent coughin a susceptible adult who serves asthe source of infection for the child.Tuberculosis deserves specialmention because of its impact worldwide.Children who are in contact witha high-risk adult are vulnerable to tuberculosisinfection. High-risk adultsare those born in countries in whichtuberculosis is endemic; residents ofcorrectional facilities, shelters, or nursinghomes; illicit drug users; personsinfected with HIV; health care workers;and the homeless.

⁷

Miscellaneous causes

. Childrenwho are exposed to first- or secondhandsmoke, environmental air pollution,or allergens may also present withchronic cough.

⁸

Congenital anatomicdefects, cystic fibrosis, and immotilecilia syndrome can cause chroniccough; typically, other symptoms ofthese disorders are evident--such asfailure to thrive, GI abnormalities, andrecurrent infection.

The importance of the historyand physical.

The clinical history offersclues to the cause of chroniccough. For example, exacerbation ofcough with exercise or meals suggestsasthma or gastroesophageal reflux disease,while unrelenting URI symptomssuggest sinusitis. Past personal andfamily history of allergies, asthma, recurrentinfections, failure to thrive, andsmoke exposure needs to be detailed.A history of travel to foreign countriesor contact with an adult with a chroniccough offers clues to the possibilityof tuberculosis or pertussis.A thorough examination--especiallyof the respiratory and GI tractsand the cardiovascular system--is indicated,and signs of pulmonary dis-ease (eg, tachypnea, wheezing, orclubbing of the nails) should besought. Positive factors in the historyand physical examination suggest theappropriate diagnostic path.

IMAGING STUDIES

The

Algorithm

outlines our approachto the child with a chroniccough. The sequence of testing is flexibleand depends on the availabilityand practicality of obtaining specifictests for specific patients.

Chest films.

We recommend obtaininga chest roentgenogram in allchildren with chronic cough. The goalis to detect any suggestion of a pulmonary,cardiac, or thoracic abnormalitythat may prompt further investigation--such as bronchoscopy or CTor MRI of the chest. Often, the chestfilm is normal, but it may reveal a possiblepneumonia, hyperinflation, atelectasis(as in a patient suffering fromasthma or foreign-body aspiration), orother cardiac and pulmonary abnormalities(Figure). Keep in mind thatnot all foreign bodies are visualized onplain chest films.

Sinus x-ray films and CT scans.

Infected sinuses should be consideredin all children with chronic cough.Whether to order a sinus x-ray film ora sinus CT scan to confirm this diagnosisis controversial, however. TheAmerican Academy of Pediatrics(AAP) recommends against imagingof the sinuses in children aged 6 yearsor younger as an aid in the diagnosisof acute bacterial sinusitis. The AAPrecommends CT scanning for patientswho are possible candidates forsurgery.

⁹

High-quality sinus x-ray films canbe nearly impossible to obtain in ayoung child, and interpretation can bequite challenging and subjective. Wehave not found sinus x-ray films to behelpful in the very young child withchronic cough, although these filmshave occasionally helped us diagnosesinus disease in older children.Although studies refer to CT asthe "gold standard,"

¹⁰

it is not alwayspractical to obtain such a scan immediately,and a child may need to be sedatedfor the procedure. Nevertheless,a CT scan can provide valuableinformation and should be consideredfor a child who is coughing persistently.At the lead author's institution,a sinus x-ray film can be obtained andreviewed within a few hours; a sinusCT scan, however, must be scheduledfor a later time--especially if sedationis required for the procedure.

DIAGNOSTIC TESTS

Pulmonary function tests. Inchildren who are able to cooperate,spirometry aids in the diagnosis ofasthma. It is possible to obtain consistentpulmonary function test results inchildren aged 5 years or younger, butthis is not always feasible.

¹¹

In theseyoung children, the diagnosis of asthmais based on a history of recurrentcough and wheezing that responds tobronchodilators, such as albuterol.

Barium swallow.

This test canprovide additional information aboutthe child's anatomy; abnormal resultsmay prompt further evaluation withCT or MRI of the chest.Consider ordering a barium swallowespecially for the child who has achronic cough during the first fewyears of life. This test may suggest thepresence of a vascular anomaly (suchas an aberrant innominate artery), amajor cause of chronic cough amongyoung children.

³

pH Probe.

If the chest film, sinusfilm, sinus CT scan, and/or bariumswallow fail to elucidate the cause ofchronic cough, a pH probe study isrecommended to determine whethergastroesophageal reflux is the underlyingproblem. Referral to a pediatricgastroenterologist for this proceduremay be warranted.

Miscellaneous tests.

Considertesting for tuberculosis with a purifiedprotein derivative test, performing asweat chloride test, and ordering anevaluation for immunodeficiency disorders.Because laboratory confirmationof many uncommon infectiousagents can be difficult, an infectiousdisease specialist should be consulted.The anatomy must be examinedvia endoscopy from the nares to thelungs and the mouth to the stomach.Endoscopy is particularly helpful in theyoung infant,

⁴

but can be helpful in personsof all ages.An allergist/immunologist canaid in the evaluation for underlying allergiesor immunodeficiency.

TREAT THEUNDERLYING CAUSE

Here we offer treatment suggestionsfor the most common causes ofchronic cough. A discussion of treatmentof various infections is beyondthe scope of this article; the Red Bookserves as an excellent source for up-todaterecommendations.

¹²

The consensuspanel report by Irwin and colleagues

¹³

summarizes the AmericanCollege of Chest Physicians' recommendationsfor managing cough; mostof these recommendations can be appliedto pediatric patients as well.At any point during the workupfor chronic cough (see

Algorithm

),you may want to consider empiric therapyfor asthma or sinusitis--especiallywhen optimal testing may not be availablebecause of the patient's age. Thesafety and cost-effectiveness of this approachhave not been established forpediatric patients (as they have foradults

^14,15

), but a trial may be desirablein some children (for example, in aninfant with a persistent cough followingan uncomplicated URI).

Asthma.

This disease must betreated aggressively so that the childis symptom-free. Anti-inflammatorymedications, such as inhaled corticosteroids--at the lowest effectivedosages--are recommended for thetreatment of all "persistent" grades ofasthma, with the possible addition ofleukotriene modifiers. Inhaled longactingβ

₂

-agonists are also recommendedwhen a child experiences se-vere persistent asthma (ie, symptomsthat occur daily and frequently atnight).

¹⁶

Inhaled short-acting β

₂

-agonistsare also used for symptom relief.The clinician's time is well-spent in educatingthe family about asthma andits treatment--and in reinforcing thateducation

Sinusitis.

The AAP recommendsantibiotic therapy for pediatric patientswith acute bacterial sinusitis but acknowledgesthat the optimal durationof therapy has not been determined.Chronic inflammation of the sinusesaccompanied by symptoms that persistfor at least 90 days may be caused bydisorders such as gastroesophagealreflux, underlying allergies, pollutionexposure, and cystic fibrosis.

⁹

As withchronic cough, the precise cause ofthe chronic sinus disease needs to bedetermined and treated. Certainly,many children suffer from asthma,allergies, and sinusitis simultaneously--and all need to be aggressivelycontrolled.

Gastroesophageal reflux

. Themany available treatment modalities--such as upright positioning, thickenedfeeding formula for very youngchildren, H

₂

blockers, proton pumpinhibitors, motility agents, and surgery--have been studied to varyingdegrees in children. The severity ofthe child's symptoms dictates the extentof therapy.

Psychogenic cough.

This phenomenoncan sometimes be alleviatedby wrapping a bedsheet tightly aroundthe patient's chest and convincing himthat the bedsheet will aid the chestmuscles in eliminating the cough.

¹⁷

Bye18 reported that a peak flow meterprovided positive feedback to an asthmaticchild suffering from a psychogeniccough and helped eliminate thatcough. Perhaps offering a non-asthmaticchild concrete evidence of a normalpeak flow may bring relief frompsychogenic cough. In some cases, abehavioral medicine consultation maybe required to stifle the psychogeniccough.

CONGENITAL ANOMALIES,FOREIGN BODIES

Congenital anomalies and otherless common causes of chronic coughoften require the expertise of a pediatricspecialist (such as a pulmonologist,cardiologist, or surgeon) for definitivetreatment. Whether they areneeded to correct an anatomic abnormality,remove a foreign body, or offerfurther treatment options, the pediatricspecialist needs to be involved. Patientswith certain illnesses, such ascystic fibrosis, require a multidisciplinaryapproach.

References:

REFERENCES:

1.

Black P. Evaluation of chronic or recurrentcough. In: Hilman CH, ed. Pediatric Respiratory Disease:Diagnosis and Treatment. Philadelphia: WBSaunders Company; 1993:143.

2

. Holinger LD. Chronic cough in infants and children.Laryngoscope. 1986;96:316-322.

3

. Bremont F, Micheau P, LeRoux P, et al. Etiologyof chronic cough in children: analysis of 100 cases.Arch Pediatr. 2001;8(suppl 3):645-649.

4

. Holinger LD, Sanders AD. Chronic cough in infantsand children: an update. Laryngoscope. 1991;101(6, pt 1):596-605.

5.

Palombini BC, Villanova CA, Araujo E, et al. Apathogenic triad in chronic cough. Chest. 1999;116:279-284.

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Mogre VS, Mogre SS, Saoji R. Evaluation of chroniccough in children: clinical and diagnostic spectrumand outcome of specific therapy. Indian Pediatr. 2002;39:63-69.

7.

Ampofo KK, Saiman L. Pediatric tuberculosis.Pediatr Ann. 2002;31:98-108.

8.

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Crenesse D, Berlioz M, Bourrier T, et al.Spirometry in children aged 3 to 5 years: reliabilityof forced expiratory maneuvers. Pediatr Pulmonol.2001;32:56-61.

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13.

Irwin RS, Boulet LP, Cloutier R, et al. Managingcough as a defense mechanism and as a symptom.A consensus panel report of the American Collegeof Chest Physicians. Chest. 1998;114:133S-181S.

14.

Lin L, Poh KL, Lim TK. Empirical treatment ofchronic cough-a cost-effectiveness analysis. ProcAMIA Symp. 2001:383-387.

15.

Ours TM, Kavuru MS, Schilz RJ, Richter JE. Aprospective evaluation of esophageal testing and adouble-blind, randomized study of omeprazole in adiagnostic and therapeutic algorithm for chroniccough. Am J Gastroenterol. 1999;94:3131-3138.

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18.

Bye MR. Use of a peak flow meter for positivefeedback in psychogenic cough. Pediatrics. 2000;106:852-853.

19.

Bell EA. Pharmacologic treatment of cough:which product to use in children? Infect Dis Children.2001;June:6-9.

20.

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