Wheezing in Children

Wheezing is a high pitched, whistling sound that occurs when smaller airways are narrowed by presence of any of the following:

• Bronchospasm
• Swelling of mucosal lining
• Excessive amounts of secretions
• Inhaled foreign body

• Common throughout childhood, except in immediate neonatal period when it relatively rare.
• 18.9% of 10 year old children shown to be wheezing on Isle of Wight with average age of onset of 3 years¹.

• Two main forms of presentation depending upon onset and age:
  • Acute onset of wheezing in an infant
  • Recurrent or persistent wheeze
• Wheezing starting perinatally suggests structural abnormalities.
• Clubbing occurs in chronic lung infection, congenital heart disease and rarely in uncomplicated asthma.
• Allergic rhinitis, urticaria and eczema suggest asthma (or an allergic reaction in a child with eczema)
• Nasal polyps are found in allergic conditions or cystic fibrosis

Acute onset of wheezing in infant - bronchiolitis

• Bronchiolitis usually presents at age 1-9 months with 2-5 day history of cold symptoms with progressive tachypnoea (may occasionally reach above100 breaths per minute), difficulty with feeding and gross hyperinflation. Fine crepitations, sometimes with rhonchi.
• Chest X-ray shows hyperinflation, occasionally with patchy areas of collapse/consolidation²
• Nasopharyngeal secretions usually tested for respiratory syncytial virus, parainfluenzae, influenza A and B, adenovirus.
• Give oxygen to maintain transcutaneous O₂ saturation at above 92%.
• Monitor heart and respiratory rates. May require IV fluids or nasogastric tube feeding.
• Antibiotics used empirically for very ill child or evidence of pneumonia with secondary bacterial infection
• Assisted ventilation via CPAP or endotracheal intubation is indicated if there is inadequate ventilation (i.e. rising CO₂ or falling oxygen saturations), severe respiratory distress, falling level of consciousness, exhaustion, cyanosis or respiratory failure.
• Infants usually recovers within 10-14 days but may have recurrent bouts of coughing and wheezing for several years³.

Recurrent or persistent wheeze

• Caused by obstruction anywhere from intrathoracic trachea to large bronchioles.
• Wheezing persisting for or recurring for more than 4 weeks is most commonly caused by reactive airways disease (asthma).
• This diagnosis is also suggested by recurring cough and response to bronchodilator therapy.

Other causes

• Cigarette smoke or other forms of pollution
• Infection-associated airways reactivity
• Asthmatic bronchitis
• Other hypersensitivity reactions
• Aspiration of foreign body: often sudden onset of severe wheezing in previously healthy child (look for tracheal deviation).
• Cystic fibrosis: most common in first year of life.
• Gastro-oesophageal reflux

Rarer causes

• Aspiration of food, saliva or gastric contents (laryngotracheo-oesophageal cleft; tracheo-oesophageal fistula; pharyngeal incoordination or neuromuscular weakness)
• Primary ciliary dyskinesia
• Heart failure
• Bronchiectasis
• Bronchiolitis obliterans
• Extrinsic compression of airways (tumours, vascular rings, etc)
• Tracheobronchomalacia
• Endobronchial masses
• Pulmonary haemosiderosis
• Sequelae of bronchopulmonary dysplasia
• 'Hysterical' glottic closure

• Chest X-ray: can demonstrate presence of foreign body, structural anomalies, enlarged heart, masses, pulmonary infiltrates
• Sweat chloride test for cystic fibrosis
• Allergy testing
• Barium swallow for tracheosophageal fistula and other anomalies⁴
• Spirometry in children aged over 6 years
  May need further investigations for rarer causes, e.g. echocardiogram, MRI/CT scan of chest