The Indian Journal of Pediatrics

, Volume 78, Issue 11, pp 1396–1400

Approach to a Child with Lower Airway Obstruction and Bronchiolitis

Authors

  • Sudhanshu Grover
    • Department of Pediatrics, Advanced Pediatrics CentrePostgraduate Institute of Medical Education and Research
  • J. Mathew
    • Department of Pediatrics, Advanced Pediatrics CentrePostgraduate Institute of Medical Education and Research
  • Arun Bansal
    • Department of Pediatrics, Advanced Pediatrics CentrePostgraduate Institute of Medical Education and Research
    • Department of Pediatrics, Advanced Pediatrics CentrePostgraduate Institute of Medical Education and Research
Symposium on PGIMER Protocols on Respiratory Emergencies

DOI: 10.1007/s12098-011-0492-z

Cite this article as:
Grover, S., Mathew, J., Bansal, A. et al. Indian J Pediatr (2011) 78: 1396. doi:10.1007/s12098-011-0492-z
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Abstract

Lower airway obstruction can occur at the level of trachea, bronchi or bronchioles. It is characterized clinically by wheeze and hyperinflated chest, apart from other signs of respiratory distress. Common causes include bronchiolitis, asthma, pneumonia, laryngotracheo-bronchitis, congenital malformations and foreign body inhalation. Bronchiolitis usually occurs in children aged 2 months to 2 years. It is most commonly caused by respiratory syncytial virus infection. The diagnosis is mainly clinical, and investigations have a very limited role. Humidified oxygen and supportive therapy are the mainstays of treatment. A trial of inhaled epinephrine or parenteral steroids may be considered for non-responders. It is usually associated with good outcome.

Keywords

ChildrenLower airway obstructionWheezeBronchiolitis

Lower Airway Obstruction

Obstruction in the lower airways (i.e. airways within the thorax) may occur in the trachea, bronchi or bronchioles. The general symptoms/signs of respiratory tract disease include cough, tachypnea, and increased respiratory effort. The most characteristic symptom and sign of lower airway obstruction is wheezing. Wheeze is a high pitched whistling sound usually heard during expiration (sometimes heard with stethoscope only). It is caused by vibrations of airways during passage of air through narrow lumen. Other relatively specific clinical pointers are prolonged expiration and hyperinflated chest. Wheeze is most often expiratory, but it may also be inspiratory or biphasic. Expiration becomes an active rather than a passive process in such cases. There are many causes of wheezing in infancy and childhood. These are summarized in Table 1. The most common among these, presenting with an acute illness in authors’ emergency department are bronchiolitis, acute asthma, pneumonia, congestive cardiac failure, laryngotracheo-bronchitis, airway foreign bodies and congenital malformations. In a study published in 2002 from a teaching hospital in north India, the common causes of wheezing in children aged 2 months to 1 year were bronchopneumonia(50%), bronchiolitis(34%), bronchial asthma(16%) after excluding foreign body inhalation, congestive cardiac failure, and anatomical malformations [1]. In Singapore, 22.7% children had at least one episode of wheeze by the second year of life [2], while in the West one-third children had at least one lower respiratory tract infection with wheeze in the first 3 years of life [3].
Table 1

Differential diagnosis of acute wheezing in infants

1. Infection

• Viral: Respiratory syncytial virus bronchiolitis, Parainfluenza, Influenza, Adenovirus, Rhinovirus, Human metapneumovirus

• Bacterial pneumonia

• Chlamydia pneumonia

2. Asthmaa

3. Aspiration syndromesa

4. Heart diseasea

• Congestive cardiac failure

• Myocarditis

• Cardiomyopathy

5. Anatomic abnormalitiesa

 • Extrinsic airway compression

 - Vascular ring/sling

 - Mediastinal lymph node/mass

 • Intrinsic airway anomalies

 - Airway hemangioma

 - Cystic adenomatoid malformation

 - Bronchial lung cyst

 - Congenital lobar emphysema

 - Sequestration of lung

 - Mediastinal lymph node/tumor/TB lymphadenitis

 • Central airway obstruction: laryngotracheo-malacia

6. Foreign body

7. Anaphylaxis

8. Inhalational injuries (burns)

9. Mucociliary clearance disordersa

• Cystic fibrosis

• Primary ciliary dyskinesia

• Bronchiectasis

10. Gastro-esophageal reflux

11. Immunodeficiencies – HIV, IgA deficiency, B-cell deficiency

aThese conditions can be associated with recurrent wheezing

Older patients with lower airway obstruction tend to breathe at a slower rate; however infants breathe faster. This is because of a highly compliant chest wall; wherein slower breathing would lead to subatmospheric intrapleural pressure and collapse of the chest wall.

Approach to a Wheezing Child

In pediatric emergency, important points in history and examination are as follows:
  • History
    • Age of onset: Onset in neonatal period/early infancy suggests CCF, anatomic malformation, or immunodeficiency.

    • Frequency: Recurrent or persistent symptoms point towards asthma, cardiac cause, or anatomical malformation.

    • A positive family history or a personal history of atopy indicates asthma.

    • Other specific symptoms like fever, cardiac symptoms, GERD may suggest the definitive cause of wheeze.

    • Previous treatment and response to the treatment is also important in making a diagnosis.

  • Examination
    • Clubbing is an indicator of chronic disease (e.g. bronchiectasis)

    • Chest shape: Barrel shaped chest is seen in asthma/chronic lung disease; precordial pulsation/bulge is seen in congenital heart disease.

    • Lateralization of findings suggests foreign body, anatomical malformations, mediastinal lymph nodes/mass.

    • Signs of allergy or atopy like rhinitis, conjunctivitis, eczema suggest asthma/allergic bronchitis.

    • Look for the signs of CCF like hepatomegaly, neck veins, dependent edema, and growth pattern.

  • Remember
    • In a child with acute onset wheezing, with history of preceding fever and abdominal pain, and presence of temperature >38°C at presentation, pneumonia is the likely diagnosis [4].

    • All infants/children with bilateral wheezing do not have bronchial asthma [4]

    • Foreign body aspiration can present with non-lateralization of findings; it should be suspected in non-responders to inhaled bronchodilators and corticosteroids [4].

    • Asthma and congenital heart disease can coexist [4].

    • In a young infant (2 to 6 months) with mild to moderate grade fever and wheeze along with respiratory distress, bronchiolitis is the most likely diagnosis.

Bronchiolitis

“Bronchiolitis” refers to inflammation of peripheral airways. It is the most common cause of wheezing in young infants.

Etiology

Respiratory syncytial virus (RSV) is responsible for more than 50% cases. Other etiologic agents include Parainfluenza, Adenovirus, Mycoplasma, and Human Metapneumovirus. Human Metapneumovirus is an important primary cause or it can occur as a co-infection. There is no evidence for a bacterial cause of bronchiolitis.

Clinical Features

  • Age—Bronchiolitis generally occurs in young infants 2 to 6 months of age. It may occur up to 2 years of age.

  • History—Fever (mild to moderate grade), refusal to feed, breathing difficulty, wheeze, lethargy

  • On examination: wheeze, hyperinflation, hyper- resonant percussion note, obliteration of liver and cardiac dullness.

Differential Diagnoses

The differential diagnoses of wheezing in infants/children are presented in Table 1. First episode of asthma, pneumonia, and congestive cardiac failure are the most important diagnoses that should be ruled out. The following points should be kept in mind.
  • First episode of bronchial asthma—often has a family history and shows good response to bronchodilators

  • Pneumonia—usually a sick looking child, with moderate to high grade fever; signs of obstruction are less pronounced; and crackles are audible on auscultation.

  • Cardiac failure due to myocarditis or congenital heart disease—is associated with tachycardia, tender hepatomegaly, basal crackles, murmur and cardiomegaly on chest radiography.

Investigations

Indications for investigations: possible alternate diagnosis, severe distress, worsening, and absence of clinical improvement.

The following investigations may be required:
  • Chest radiograph

  • Viral studies (nasopharyngeal swab): Nasopharyngeal swab may be positive for RSV.

  • Blood gas analysis

Chest radiograph provides information about the baseline lung condition for any infant with respiratory distress and helps to rule out other differential diagnoses such as foreign body and pneumonia, and to look at chronic lung conditions e.g. bronchiectasis. In bronchiolitis, it typically shows hyperinflation and patchy atelectasis.

Figure 1 shows a typical chest radiograph of bronchiolitis. This one and a half month infant was brought with fever and paroxysmal cough for 4 days. Long bouts of cough were associated with apnea. He had family history of asthma. On examination: respiratory rate was 65/min with chest wall retractions, decreased air entry and wheeze and scattered crepts all over chest. Nasophryngeal swab was positive for Respiratory Syncitial Virus.
https://static-content.springer.com/image/art%3A10.1007%2Fs12098-011-0492-z/MediaObjects/12098_2011_492_Fig1_HTML.jpg
Fig. 1

Chest radiograph of a two and a half month infant, with bronchiolitis showing bilateral hyperinflation (hyperaerated lungs, widening of intercostals space, straightening of ribs).

Treatment

An outline of treatment plan for suspected cases of bronchiolitis is given in Fig. 2.
https://static-content.springer.com/image/art%3A10.1007%2Fs12098-011-0492-z/MediaObjects/12098_2011_492_Fig2_HTML.gif
Fig. 2

Flowchart showing outline of management in suspected case of bronchiolitis

  1. 1.

    Humidified oxygen is the mainstay of treatment in bronchiolitis.

     
  2. 2.

    Careful attention to fluid therapy is necessary; liberal fluid therapy may lead to water intoxication [5]. Bronchiolitis of infancy is characterized by water retention which is caused by impaired renal water excretion.

     

Other modalities of treatment have been studied extensively. These include inhaled epinephrine, parenteral steroids (dexamethasone), inhaled salbutamol, inhaled hypertonic saline etc. Their role is unproven; none of them is supported by robust evidence of significant clinical efficacy.

Nebulized Epinephrine

Epinephrine has been aptly described as the “least ineffective” intervention [6, 7]. There is no benefit in terms of admission rate or duration of hospitalization; however subgroup analysis suggests that epinephrine has some benefit among outpatients. Similarly, there is no difference for surrogate outcomes including change in oxygen saturation, heart rate and respiratory rate, although epinephrine results in more favourable clinical score change from baseline. A meta-analysis of the treatment effects of nebulized epinephrine suggested a decrease in clinical symptoms as compared with either placebo or salbutamol [8].Nebulized epinephrine has been shown to improve symptoms better than oral or nebulized salbutamol [911].

Some infants may experience worsening of symptoms with nebulized epinephrine. Therefore, a trial should be considered but treatment should be stopped if there is no response.

Nebulized Salbutamol

There is no benefit of inhaled salbutamol on admission rate or duration of hospitalization [12]. A meta-analysis of the treatment effects of nebulized selective beta-agonists failed to show any consistent benefits [13].

Nebulized Hypertonic Saline

It has been suggested that hypertonic saline nebulization may be useful in making secretions less viscous and promoting their excretion, thereby resulting in clinical improvement. However, nebulized hypertonic saline has a limited role in bronchiolitis [14].

Steroids (Oral/Inhaled)

Steroids are no different from placebo with respect to hard outcomes and several surrogate outcomes (clinical scores, oxygenation parameters, respiratory rate, readmission rate). One trial (n = 174) showed that a single dose of intravenous dexamethasone (0.6 mg/kg) results in (statistically but not clinically significant) shorter duration of hospitalization and time for resolution of respiratory distress [15, 16].

Inhaled dexamethasone does not show any difference in clinical score and oxygenation compared to saline [17].

A recent randomized controlled trial studied 800 patients divided in 4 intervention groups: 1) Epinephrine–dexamethasone group, 2) Epinephrine group 3) Dexamethasone group 4) Placebo group. The doses used were:- Epinephrine: 3 ml of generic epinephrine in a 1:1000 solution; Dexamethasone: 1.0 mg/kg body weight (maximum dose, 10 mg) or placebo given after the first nebulized treatment in the emergency department, followed by five once-daily doses of dexamethasone (0.6 mg/kg; maximum daily dose, 10 mg). The study concluded that combined therapy with dexamethasone and epinephrine may significantly reduce hospital admissions [18].

Ribavirin (Aerosol)

Ribavirin should not be used routinely in children with bronchiolitis [19]. Indications for using ribavirin include selected patients with life threatening RSV infection [20]: such as prematurity, infants with congenital heart disease, chronic lung disease and immunocompromised host.

One systematic review and two subsequent RCTs found that, in children and infants admitted to hospital with RSV bronchiolitis, ribavirin did not significantly reduce mortality, respiratory deterioration, or duration of hospital stay compared with placebo [21], but it significantly reduced the duration of ventilation compared with placebo [22].

Use of CPAP (Continuous Positive Airway Pressure)

A recent randomized controlled trial (n = 31) compared the use of nasal CPAP with standard treatment. CPAP improved ventilation and hypercapnea [23].

Treatment Modalities That Should Be Avoided

  • Chest physiotherapy should not be used routinely in the management of bronchiolitis.

  • No antibiotics should be given routinely [19].

Indications for Hospitalization

Indications for hospitalization are mentioned in Table 2.
Table 2

Indications for hospitalization/markers for severe disease

• Age less than 3 months

• Gestational age at birth < 34 weeks

• Cardiopulmonary disease/immunodeficiencies

• Anatomical defects of airways

• Neurological disease associated with hypotonia and pharyngeal in-coordination

• Respiratory rate > 70/min

• Lethargic appearance

• Wheezing and respiratory distress associated with SpO2 < 92%

• Atelectasis or consolidation on chest radiography

Criteria for Discharge

The following criteria are recommended for sending home an infant with bronchiolitis [24]:
  • Normal respiratory rate

  • Oxygen concentration of at least 94%

  • Adequate oral intake

  • Absence of respiratory distress

Conflict of Interest

None.

Role of Funding Source

None.

Copyright information

© Dr. K C Chaudhuri Foundation 2011