Common childhood illness usually caused by inflammation of the upper respiratory tract as a result of (usually viral) infection

Aetiology

• Typically affects children aged 6 months old to 6 years old; most common in children aged under 3 years old
• Majority of cases in autumn and winter
• Most commonly caused by parainfluenza virus I, can also be caused by parainfluenza virus types II, III, IV, RSV, adenovirus and others
  • Bacteria can also cause croup, and these cases are a lot more severe

Pathophysiology

• Viral upper respiratory tract infection (URTI) causes nasopharyngeal inflammation that may spread to the larynx and trachea, causing subglottal inflammation, oedema and compromise of the airway at its narrowest portion
• The movement of the vocal cords is impaired leading to the characteristic cough

Clinical features

• Normally starts with nonspecific symptoms of viral URTI - runny nose, sore throat, fever and cough
• This progresses over the course of a couple of days to include increased work of breathing, characteristic barking cough, hoarseness and stridor; these symptoms tend to be worse at night

Investigations

• Usually clinical diagnosis

Management

• Most children will have mild croup, which can be managed at home
• Mild croup (seen in most children) is largely self-limiting and can be managed at home, but treatment with a single dose of a corticosteroid (e.g. dexamethasone) by mouth may be of benefit
• In moderate-severe croup requiring hospital admission:
  1. Oral dexamethasone - if too unwell to receive oral medication can give IM dexamethasone or nebulised budesonide
  2. Oxygen
  3. Nebulised adrenaline - if significant concerns about the airway
  4. Intubation and ventilation
• It is vital not to upset children with croup as their crying can worsen their upper airway obstruction