Basics
Description
A high-velocity expulsion of gas from the airways that serves to clear them of mucus, cellular and microbial debris, or foreign bodies. An absence or inability to cough can lead to recurrent pneumonia. Cough can be acute (<2 weeks), subacute/protracted (2-4 weeks), or chronic (>4 weeks).
Epidemiology
Cough is the most common symptom presenting to primary care physicians in the United States and worldwide. Chronic cough accounts for up to 9% of chief complaints to U.S. pediatricians.
Healthy children can have a nonpathologic cough. School-age children typically experience 10 cough episodes per day.
Pathophysiology
Cough results from a complex reflex phenomenon initiated by cough receptors that is mediated through the brainstem. The receptors are located in the respiratory tract from the larynx to the segmental bronchi, paranasal sinuses, external auditory canal, and stomach and are triggered by thermal, chemical, mechanical, or inflammatory stimuli. Cough is generally reflexive but may sometimes be voluntarily initiated or suppressed.
Diagnosis
Differential Diagnosis
Infection and asthma are the most common causes of cough in all pediatric age groups and should always be considered.
Children have an average of 6-8 upper respiratory infections (URIs) per year, with each lasting up to 2-3 weeks. Roughly 1/3 of preschool-aged children cough more than 10 days after a cold, and 10% of preschool children cough more than 25 days after a cold.
- Causes of acute (<2 weeks) or subacute/protracted (2-4 weeks) cough
- Infection
- Reactive airway disease (RAD)
- Sinusitis
- Irritants
- Allergy
- Foreign body
- Causes of chronic (>4 weeks) cough
- Bronchitis
- Postinfectious
- Sinusitis
- Asthma
- Irritants (cigarette smoke exposure, air pollution)
- Allergic rhinitis
- Foreign body
- Gastroesophageal reflux (GER)
- Habitual or psychogenic
- Anatomic abnormalities: tracheoesophageal fistula, tracheobronchomalacia, laryngeal cleft, polyps, adductor vocal cord paralysis, pulmonary sequestration, bronchogenic cyst, cystic hygroma, vascular ring, tumor
- Cystic fibrosis (CF)
- Ciliary dyskinesia
- Immunodeficiency states that result in recurrent respiratory infections: HIV, immunoglobulin deficiencies (IgA, IgG), phagocytic defects, complement deficiency
- Interstitial lung disease
- Angiotensin-converting enzyme inhibitors
- Stimulation of external auditory canal cough receptors (Arnold reflex cough)
Approach to the Patient
Given the common nature of cough and the large differential diagnosis it generates, an extremely thorough history and physical exam (H&P) should direct a rational, stepwise approach.
History
- Question: How long has the child coughed?
- Significance: Most acute and subacute coughs are associated with viral URIs. Pediatric chronic cough is defined as daily cough that lasts for >4 weeks.
- Question: Is there a recent history of URI?
- Significance: Serial URIs, the most common cause of chronic cough in children, can be diagnosed by a careful history of waxing and waning symptoms and will avoid unnecessary tests. Also consider postinfectious cough (due to heightened cough receptor sensitivity) or sinusitis (which complicates up to 5% of URIs). Overall, 8-12% of children with URIs develop complications.
- Question: What are the associated symptoms?
- Significance:
- Fever and nasal discharge suggests infection.
- Fever with chills or night sweats suggests TB in children with chronic cough.
- With rhinorrhea, halitosis, headache, or facial edema, consider sinusitis.
- With respiratory distress, suspect RAD, infection, or foreign body.
- Question: What is the quality of the cough?
- Significance:
- Acute wet cough suggests upper or lower airway respiratory infection or asthma.
- Subacute wet cough suggests sinusitis, bronchitis, or asthma.
- Chronic wet cough is always abnormal and can be associated with sinusitis, bronchitis, asthma, CF, ciliary dyskinesia, bronchitis, or anatomic lower airway abnormality such as tracheomalacia.
- Dry cough can suggest asthma.
- Barking cough is usually associated with croup.
- Brassy cough is associated with tracheomalacia.
- A honking or barking chronic cough that increases during times of stress and is absent during sleep is typical for habit cough.
- Staccato cough suggests chlamydial pneumonia in infants.
- Paroxysmal cough, with or without whoop, suggests pertussis or parapertussis.
- Question: What is the pattern of the cough?
- Significance:
- Chronic nighttime cough suggests RAD, postnasal drip from allergic rhinitis, or GERD.
- With nighttime/early morning cough, consider sinusitis or allergic rhinitis.
- Seasonal cough suggests allergy.
- Question: Are there any known triggers of cough (e.g., smoke, cold air, dust, URI)?
- Significance: Consider irritant, allergy, or RAD.
- Question: Is there any personal or familial history of atopy?
- Significance: Consider RAD.
- Question: Are there recurrent infections?
- Significance: Consider immunodeficiency, CF. Consider pulmonary sequestration if patient has recurrent pneumonias in same location.
- Question: Is there any relation of cough to feedings?
- Significance: Consider aspiration, GER, laryngeal cleft, and tracheoesophageal fistula.
- Question: Is there a history of a choking episode?
- Significance: Consider retained foreign body.
- Question: Is there exercise intolerance?
- Significance: Consider asthma, interstitial lung disease
- Question: What is the parental level of concern?
- Significance: Children's cough generates significant parental stress and concerns, and appreciation of parental worries is valuable when addressing this problem.
Physical Exam
Assess patient's general appearance
- Finding: Evidence of failure to thrive?
- Significance: Consider TB, CF, immunodeficiency, aspiration
- Finding: Cyanosis or pallor?
- Significance: Consider pneumonia, asthma
- Finding: Signs of respiratory distress such as tachypnea, accessory muscle use?
- Significance: Consider pneumonia, asthma, congenital anatomic abnormalities
- Finding: Barrel chest?
- Significance: Suggests air trapping due to chronic disease
- Finding: Clubbing?
- Significance: Consider CF, ciliary dyskinesia, interstitial lung disease, chronic aspiration
- Finding: Nasal polyp?
- Significance: Must rule out CF. Also seen with allergic rhinitis.
- Finding: Tracheal deviation?
- Significance: Suggests mediastinal mass or foreign body aspiration
- Finding: Signs of atopic disease such as eczema, allergic shiners, transverse nasal crease, rhinitis, mucosal cobblestoning, injected conjunctivae?
- Significance: Allergic rhinitis
- Finding: Rhinorrhea/purulent posterior pharyngeal drainage, sniffling, halitosis, periorbital edema, sinus tenderness?
- Significance: Suggest sinusitis
- Finding: Crackles (rales)?
- Significance: Coarse crackles suggest bronchiectasis; fine crackles suggest pneumonia, atelectasis, pulmonary edema, and interstitial lung disease.
- Finding: Rhonchi
- Significance: Bronchitis, impaired cough (from weakness, tracheostomy)
- Finding: Decreased breath sounds
- Significance: Suggests pneumonia, pleural effusion, chest mass
- Finding: Wheezing?
- Significance:
- Polyphonic inspiratory or expiratory wheezes suggest RAD.
- Monophonic or fixed wheezes should make one consider foreign body or mass/congenital lesion.
Diagnostic Tests & Interpretation
- Laboratory investigation should reflect a rational, stepwise approach based on likely etiologies after a thorough history.
- Evidence-based clinical practice guidelines for evaluating chronic cough in pediatrics were published in 2006. In general, children with chronic cough should have a chest radiograph, and spirometry should be considered for children >4 years of age.
- Test: chest x-ray posteroanterior/lateral
- Significance: Detect infection, foreign body, chronic aspiration, interstitial lung disease, pulmonary edema, diaphragmatic hernia, signs typical for asthma, CF
- Test: Spirometry
- Significance: Detect airway obstruction or lung restriction. Pre- and post-bronchodilator response is useful to diagnose asthma.
- Test: Microbiology workup as indicated (e.g., polymerase chain reaction [PCR] for pertussis, direct fluorescent antibody [DFA] for viral panel, culture for Chlamydia)
- Significance: Aids in precise diagnosis and treatment as needed
- Test: Paranasal sinus CTscan
- Significance: Should be used judiciously to evaluate sinus disease, that is, for complications of sinusitis, recurrent sinusitis
- Test: CBC
- Significance: Eosinophilia suggests atopic disease or, rarely, parasitic infection; anemia should prompt one to consider chronic disease or, rarely, pulmonary hemosiderosis; leukocytosis suggests infection.
- Test: Bronchoscopy
- Significance: Diagnose presence of foreign body, and airway anomalies (laryngeal cleft, tracheobronchomalacia, tracheoesophageal fistula [TEF], vascular ring) and perform alveolar lavage for cultures, cytology, hemosiderin-laden macrophages (suggests alveolar bleeding), lipid-laden macrophages (suggest aspiration)
- Test: Barium swallow
- Significance: Aspiration
- Test: Upper GI series
- Significance: Vascular ring
- Test: Mantoux test: purified protein derivative (PPD) skin test
- Significance: To diagnose TB
- Test: Serum IgE
- Significance: Significant elevation indicates allergy or, rarely, allergic bronchopulmonary aspergillosis
- Test: Sweat test
- Significance: To diagnose CF, but need to be sure that laboratory has experience with this test
- Test: Immune workup
- Significance: HIV, immunodeficiency
- Test: pH probe
- Significance: GER
- Test: High-resolution CT scan of the thorax, video fluoroscopy, echocardiogram, or nuclear medicine scans
- Significance: May be judiciously used; generally reserved until after referral to a specialist
Imaging
Chest x-ray
- Infiltrates may suggest pneumonia, bronchiolitis, pneumonitis, TB, CF, bronchiectasis, or foreign body.
- Volume loss may be seen with foreign body aspiration; sometimes need to obtain lateral decubitus views in young children who cannot cooperate with inspiratory/expiratory views.
- Hyperinflation suggests RAD or CF.
- Mediastinal nodes may indicate infection (especially TB or fungal) or malignancy.
Treatment
Additional Treatment
General Measures
- Cough should be treated based on etiology.
- OTC cough medicines are widely prescribed and overused.
- The U.S. Food and Drug administration (FDA) and Consumer Healthcare Products Association recommend avoiding OTC cough and cold medicines in children <4 years of age. An American Academy Pediatrics position statement questions the efficacy and safety of these medications in children <6 years of age.
- To avoid overuse of antibiotics, parents should be informed that viral URI can cause cough that commonly lasts up to 2-3 weeks.
- Educate parents about the beneficial function of cough to remove irritants and about the potential harm of suppressing a productive cough or cough secondary to RAD.
- Honey may be used in children older than age 1 year. Acute cough from URI or chronic nonspecific cough (i.e., dry cough in the absence of asthma or other identifiable disease) may be safely, effectively, and inexpensively treated with honey.
- Specific pharmacologic interventions:
- RAD: Bronchodilators ± inhaled anti-inflammatory agents, oral or inhaled steroids, removal of irritants
- Infection: Appropriate antibiotics as indicated. May be considered in cases of chronic productive cough or pneumonia.
- Antihistamines (nonsedating) should be used only when cough coexists with rhinitis.
- Self-hypnosis is a safe, effective treatment for children with habit cough.
- Children with "nonspecific cough" (i.e., without specific indicators by H&P as noted earlier) generally do not derive much benefit from medications and may undergo a period of "watchful waiting." If medications are used, patients need to be reassessed in 2-3 weeks.
Issues for Referral
- The vast majority of cases of cough, even when chronic, can be diagnosed and managed by the primary care physician.
- Factors in making a referral:
- The cough is unresponsive to treatment.
- The cause is likely to be an anatomic malformation or foreign body aspiration.
- There appears to be involvement of other organ systems (e.g., failure to thrive, CF, congestive heart failure, immunodeficiency, unusual infection).
- Hemoptysis
Admission Criteria
- Cough should be considered an emergency if there are associated signs or symptoms of respiratory distress.
- Routine emergency airway assessment should be undertaken on presentation and appropriate supportive measures started in cases in which there is concern.
Additional Reading
- Anbar RD, Hall HR. Childhood habit cough treated with self-hypnosis. J Pediatr. 2004;144(2):213-217. [View Abstract]
- Carr BC. Efficacy, abuse, and toxicity of over-the-counter cough and cold medicines in the pediatric population. Curr Opin Pediatr. 2006;18(2):184-188. [View Abstract]
- Chang AB. American College of Chest Physicians cough guidelines for children: can its use improve outcomes? Chest. 2008;134(6):1111-1112. [View Abstract]
- Chang AB. Cough. Pediatr Clin North Am. 2009;56(1):19-31. [View Abstract]
- Chang AB, Glomb WB. Guidelines for evaluating chronic cough in pediatrics. Chest. 2006;129(1)(Suppl):260S-283S. [View Abstract]
- Goldsobel AB, Chipps BE. Cough in the pediatric population. J Pediatr. 2013;156(3):352-358. [View Abstract]
- Gupta D, Verma S, Vishwakarma SK. Anatomic basis of Arnold's ear-cough reflex. Surg Radiol Anat. 1986;8(4):217-220. [View Abstract]
- Marchant JM, Morris PS, Gaffney J, et al. Antibiotics for prolonged moist cough in children (Review). The Cochrane Library. 2011;2:1-25. [View Abstract]
- Marchant JM, Newcombe PA, Juniper EF, et al. What is the burden of chronic cough for families? Chest. 2008;134(2):303-309. [View Abstract]
- Mulholland S, Chang AB. Honey and lozenges for children with non-specific cough (Review). The Cochrane Library. 2011;(2):1-14. [View Abstract]
Codes
ICD09
- 786.2 Cough
- 460 Acute nasopharyngitis [common cold]
- 493.9 Asthma, unspecified type, without mention of status asthmaticus
- 490 Bronchitis, not specified as acute or chronic
- 530.81 Esophageal reflux
ICD10
- R05 Cough
- J00 Acute nasopharyngitis [common cold]
- J45.909 Unspecified asthma, uncomplicated
- J40 Bronchitis, not specified as acute or chronic
- K21.9 Gastro-esophageal reflux disease without esophagitis
SNOMED
- 49727002 Cough (finding)
- 82272006 Common cold (disorder)
- 195967001 Asthma (disorder)
- 32398004 Bronchitis (disorder)
- 235595009 Gastroesophageal reflux disease (disorder)
FAQ
- Q: Is whooping cough still a problem despite routine childhood immunization?
- A: Yes. Pertussis often goes unrecognized as a cause of acute and chronic cough, particularly in infants who have not completed their immunization series and in older children, adolescents, and adults. Immunity from vaccination or natural infection may wane within 5 years, thus providing a reservoir of pertussis in the community. Tdap vaccination is recommended for all 11 years of age and older.
- Q: How can an ear examination help explain the cause of chronic cough?
- A: For some patients, the presence of cerumen, a foreign body, or irritation of the external auditory ear canal can stimulate the auricular branch of the vagus nerve ("Arnold nerve") and trigger a cough. This is also known as the oto-respiratory reflex. One study conducted in India suggests a 4% prevalence of this phenomenon.