A CHILD WITH NOISY BREATHING

The most likely diagnosis is laryngotracheobronchitis (croup). This child has stridor, which is an inspiratory sound secondary to narrowing of the upper airway. In contrast, wheeze is an expiratory sound caused by narrowing of the lower airways. The effort required to shift air through the narrowed airway has resulted in tachypnoea and recession. The upper airway of a child with stridor should not be examined and the child should not be upset by performing painful procedures such as blood tests. This is because there is a small risk that this may lead to a deterioration, causing partial obstruction to progress to complete obstruction and a respiratory arrest.

Differential diagnosis of acute stridor

• Laryngotracheobronchitis

• Inhaled foreign body

• Anaphylaxis

• Epiglottitis

• Rare causes include:

– Bacterial tracheitis

– Severe tonsillitis with very large tonsils

– Inhalation of hot gases (e.g. house fire)

– Retropharyngeal abscess

Croup typically occurs in children aged 6 months to 5 years. It is characterized by an upper respiratory tract infection that is followed by a barking-type cough, a hoarse voice, stridor and a low-grade fever. Croup is most commonly caused by the parainfluenza virus. When a foreign body is inhaled, there is usually a history of sudden coughing and/or choking in a child that was previously well. There may be accompanying cyanosis. The foreign body is usually a food (e.g. peanut) but may be a small toy. On examination there may be a unilateral wheeze with decreased air entry on one side. This case is not typical of anaphylaxis, in that there is no history of the child having had peanuts. Nor are there features that often accompany anaphylaxis, such as an itchy urticarial rash, facial swelling, vomiting, wheeze or hypotension. Epiglottitis would be very unlikely in a fully immunized child who would have received the Haemophilus influenzae vaccine. Initial management deals with the ABC. As the oxygen saturation is low, high-flow 100 per cent oxygen will be needed to elevate the saturation to 95 per cent. The first step in the treatment of croup is oral dexamethasone. A less frequently used alternative is nebulized budesonide. If 2–3 hours later the child has improved and the oxygen saturation is 95 per cent in air, the child can be discharged. In some cases a further dose of steroids can be administered 12–24 hours later. If the child deteriorates then nebulized adrenaline can be administered. If adrenaline is required then senior help and an anaesthetist should be summoned urgently. If the child deteriorates further (increasing tachypnoea, recession and exhaustion) then intubation and ventilation are   required to secure the airway and to prevent hypoxia and its sequelae. If intubation is unsuccessful, an ENT surgeon will be required to perform an emergency tracheostomy.

KEY POINTS

• Stridor is due to upper airway obstruction.

• The upper airway of a child with stridor should not be examined as this may precipitate total obstruction.

• Laryngotracheobronchitis is the commonest cause of acute stridor.