Cough

The 5 Minute Pediatric Consult


	Cough

Margaret McNamara

Database
Differential Diagnosis
Approach to the Patient
Data Gathering
Physical Examination
Laboratory Aids
Emergency Care
Common Questions and Answers
Bibliography

DATABASE

DEFINITION

Cough is a symptom of a variety of underlying conditions, which results from a complex reflex phenomenon initiated by cough receptors and mediated in the brainstem’s cough center. These receptors are located throughout the large- to medium-sized airways (and not the lower airways), pharynx, paranasal sinuses, external auditory canal, and stomach, and are triggered by thermal, chemical, mechanical, or inflammatory stimuli. The resultant high velocity expiration, which removes airway secretions, is generally reflexive, but may sometimes be voluntarily initiated or suppressed.

DIFFERENTIAL DIAGNOSIS

Infection and reactive airway disease are the most common causes of cough in all age groups and should always be considered.

CAUSES OF ACUTE COUGH

Infection
Reactive airway disease (RAD)
Sinusitis
Irritative
Allergic
Foreign body

CAUSES OF CHRONIC COUGH

Infection
Asthma or asthmatic bronchitis
Sinusitis
Irritative/Post-infectious
Allergic
Foreign body (FB)
Gastroephageal reflux (GER)
- Aspiration
Habitual or psychogenic
Anatomic abnormalities
- Tracheoesophageal fistula
- Tracheobroncheomalacia
- Laryngeal cleft
- Polyps
- Adductor vocal cord paralysis
- Pulmonary sequestration
- Bronchogenic cyst
- Cystic hygroma
- Vascular ring
- Tumor
Cystic fibrosis (CF)
Ciliary dyskinesia syndromes
Immunodeficiency states
- Human Immunodeficiency Virus (HIV)
- Immunoglobulin deficiencies (IgA, IgG)
- Phagocytic defects
- Complement deficiency
Pulmonary hemosiderosis
Angiotensin-converting enzyme inhibitors
External auditory canal irritation

APPROACH TO THE PATIENT

GENERAL GOAL

The presenting symptom of cough is a familiar one to most physicians and accounts for nearly 7% of chief complaints to pediatricians. Cough is an easily identifiable symptom that frequently provokes parental concern and can be troublesome to the physician. The possible etiologies of cough are diverse, and may range from a minor illness to a life-threatening condition. Therefore, a stepwise approach is required in an effort to prevent a costly and lengthy investigation. In particular, a thorough history and physical examination are of paramount importance in the evaluation.

Phase 1: Complete history and physical examination to determine time course and severity of cough and to ascertain whether it represents a significant problem of respiratory function or a serious underlying disease.

Phase 2: Initiate focused work-up and treatment plan depending on differential diagnosis (see previous section).

Phase 3: Refer to pediatric pulmonologist if cough persists or if concerned about significant pathology (see following section).

DATA GATHERING

HISTORY

Question: Is the cough acute or chronic?
Significance: Generally considered to be chronic if present longer than 3 weeks. Although there is significant overlap, differential diagnosis varies depending on the time course.

Question: How is this problem different in children as compared with adults?
Significance: Differential diagnosis varies considerably based on the patient’s age.

Question: Is there a recent history of upper respiratory infection (URI)?
Significance: Consider serial URIs (children have average of 6 to 8 per year with each lasting up to 2 weeks), post-infectious/irritative or sinusitis (which complicates up to 5% of URIs).

Question: What are the associated symptoms?
Significance:

Fever, nasal discharge suggest infection.
Fever with chills or night sweats suggests tuberculosis.
Sputum production indicates bronchiectasis or other lower airway pathology.
With headache or facial edema, consider sinusitis.
With respiratory distress, suspect RAD.

Question: What is the quality of the cough?
Significance:

Productive cough suggests lower airway infection, CF/bronchiectasis.
Dry cough suggests RAD, fungal infection.
Barking cough is usually associated with croup.
Honking or brassy cough is typical in habitual or psychogenic cough.

Question: What is the pattern of the cough?
Significance:

Night-time cough suggests RAD.
With night-time/early morning cough, consider sinusitis.
Seasonal cough suggests allergy.

Question: Are there any known triggers of cough (e.g., cold air, dust, smoke, URI)?
Significance: Consider irritant, allergic, or reactive airway disease.

Question: Is there any personal or familial history of atopy?
Significance: Consider RAD.

Question: Is there a history of recurrent infections?
Significance: Consider immunodeficiency, CF.

Question: Is there any relation of cough to feedings?
Significance: Consider aspiration, tracheoesophageal fistula.

Question: Is there a history of a choking episode?
Significance: Consider retained foreign body, although there may not be a history of a choking episode in this case and cough may be episodic as FB moves along respiratory tract.

Question: Is there failure to thrive?
Significance: Rule out CF, immunodeficiency.

PHYSICAL EXAMINATION

Finding: Patient’s general appearance
Significance:

Evidence of failure to thrive—consider CF, immunodeficiency.
Cyanosis or pallor—rule out hypoxemia.
Signs of respiratory distress such as tachypnea, accessory muscle use—most likely RAD or infection.

Finding: Barrel chest
Significance: Suggests air-trapping due to chronic disease.

Finding: Clubbing
Significance: May be seen with bronchiectasis.

Finding: Nasal polyps
Significance: May be associated with allergic conditions or CF.

Finding: Tracheal deviation
Significance: Suggests mediastinal mass or FB aspiration.

Finding: Signs of atopic disease
Significance: Eczema, allergic shiners, transverse nasal crease, rhinitis, mucosal cobblestoning, injected conjunctivae suggest allergy, RAD.

Finding: Periorbital edema, sinus tenderness, purulent posterior pharyngeal drainage, halitosis
Significance: Sinusitis

Finding: Wheezing
Significance: Polyphonic inspiratory or expiratory wheezes suggest RAD, while monophonic or fixed wheezes should make one consider FB or mass/congenital lesion.

LABORATORY AIDS

Laboratory investigation should reflect a rational, stepwise approach based on likely etiologies after a thorough history and physical examination.

Test: Chest radiograph
Significance:

Infiltrates may suggest pneumonia, bronchiolitis, pneumonitis, TB, CF, bronchiectasis, FB.
Volume loss may be seen with FB 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, fungus) or malignancy.

Test: Mantoux test—purified protein derivative (PPD)
Significance: Rule out tuberculosis

Test: Complete blood count
Significance: Eosinophilia suggests atopic disease or, rarely, parasitic infection; anemia should prompt one to consider chronic disease or, rarely, pulmonary hemosiderosis.

Test: Sputum sample must contain alveolar macrophages
Significance:

Eosinophils suggest asthmatic process or hypersensitivity reaction of lung.
Polymorphonuclear cells suggest infection.
Predominance of macrophages suggests post-infectious hyperresponsive cough receptors.
Hemosiderin staining suggests pulmonary hemosiderosis.
Lipid-laden macrophages suggest recurrent aspiration.
Routine or special cultures based on likely pathogens.

Test: Serum IgE
Significance: Significant elevation indicates allergy or, rarely, parasites.

Test: Sweat chloride test
Significance: Need to be sure that laboratory has experience with this test.

Test: Wright peak flow rate
Significance:

Easy to perform in the office with the proper flowmeter.
Helpful to get pre-bronchodilator and post-bronchodilator rates if RAD suspected.
Standardized tables available with values based on height and race.

Test: Immune work-up
Significance: HIV; immunoglobulins

Test: Barium swallow or pH probe
Significance: Reflux

Test: Bronchoscopy
Significance: To remove FB or obtain tissue samples.

EMERGENCY CARE

Cough should be considered an emergency if there are associated signs or symptoms of respiratory distress.
Routine emergency airway assessment (i.e., ABCs) should be undertaken on presentation and appropriate supportive measures started in cases in which there is concern.
Refer for additional treatment as outlined previously.

COMMON QUESTIONS AND ANSWERS

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 adolescents (and adults) in whom immunity from vaccination will have waned.

Q: Is it possible for a child to have asthma if they have never wheezed?
A: Yes, there is cough-variant reactive airway disease.

Issues for Referral

Factors that may alert you to make a referral include:

The cough is unresponsive to treatment.
The cause is likely to be an anatomic malformation or FB aspiration.
There appears to be involvement of other organ systems (e.g., failure to thrive, GER, congestive heart failure, immunodeficiency, unusual infection).
There is hemoptysis.

Clinical Pearls

The goal is to treat the underlying cause of the cough, not the symptom.
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.
Specific pharmacologic interventions:
- RAD: bronchodilators ±inhaled antiinflammatory agents (e.g., cromolyn sodium), oral or inhaled steroids, removal of irritants
- Infection: appropriate antibiotics
- Cough suppressants have not been shown to be efficacious in children under 5 years, and have been associated with significant toxicity in this age group.

BIBLIOGRAPHY

Committee on Drugs. Use of codeine and DM-containing cough remedies in children. Pediatrics 1997;99(6):918–920.

Kamei RK. Chronic cough in children. Pediatr Clin North Am 1991;38(3):593–605.

Katcher ML. Cold, cough and allergy medications: uses and abuses. Pediatr Rev 1996;17(1):12–17.

Kemper KJ. Chronic asthma: an update. Pediatr Rev 1996;17(4):111–117.

Taylor JA, Novack AH, Almquist JR, Rogers JE. Efficacy of cough suppressants in children. J Peds 1993;122(5):799–802.

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