17  Croup

17.1 Introduction

Croup, medically known as laryngotracheobronchitis, is a common acute upper respiratory illness in children, characterized by inspiratory stridor, a barking cough, and hoarseness. It typically results from a viral infection that causes inflammation of the larynx, trachea, and bronchi. Though it is usually self-limiting, it can occasionally lead to life-threatening airway obstruction. Croup is particularly important for medical students and healthcare providers in Ghana, where respiratory infections are a leading cause of childhood morbidity, particularly during the rainy season when viral infections peak.

17.2 Epidemiology

• Age group: Primarily affects children between 6 months and 5 years. The peak incidence occurs around 2 years of age.
• Gender: Males are slightly more affected than females.
• Seasonality: Most cases occur during the rainy or cold seasons (June to October in Ghana), coinciding with an increase in viral respiratory infections.
• Prevalence: Although there is limited Ghana-specific data, studies across sub-Saharan Africa indicate that viral croup accounts for a significant proportion of paediatric respiratory admissions, particularly in urban areas such as Accra and Kumasi.

17.3 Etiology

Viral infections most commonly cause croup. The Parainfluenza virus type 1 is the most frequent cause globally and in Ghana.

Common viral agents:

• Parainfluenza viruses (types 1, 2, 3)
• Respiratory syncytial virus (RSV)
• Influenza A and B
• Adenoviruses
• Rhinoviruses
• Coronavirus (including some SARS-CoV-2 variants)

These viruses infect and inflame the epithelial lining of the upper airway, leading to swelling, increased mucus, and narrowed air passages, especially in the subglottic region.

17.4 Pathophysiology

The hallmark of croup is subglottic inflammation. In the paediatric airway, the narrowest part is the subglottic space, located just below the vocal cords. Viral infection triggers:

• Mucosal oedema
• Cellular infiltration
• Increased mucus production

These changes reduce airway diameter, particularly during inspiration, leading to:

• Stridor (turbulent airflow)
• Barking cough (from irritated vocal cords)
• Respiratory distress in severe cases

Young children are especially vulnerable due to their smaller airway diameter and less developed respiratory musculature.

17.5 Clinical Features

The classic presentation involves:

Prodromal Phase:

• Begins with non-specific upper respiratory symptoms:

  • Nasal congestion
  • Rhinorrhoea
  • Low-grade fever
  • Mild cough

Croup Syndrome:

• Barking cough (seal-like)
• Hoarseness
• Inspiratory stridor (worse with agitation or crying)
• Respiratory distress (tachypnoea, nasal flaring, retractions)
• Fever (low to moderate)

Symptoms often worsen at night, leading to sudden parental concern.

Severity Classification:

1. Mild:
   • Occasional barking cough
   • No stridor at rest
   • No retractions
2. Moderate:
   • Frequent cough
   • Stridor at rest
   • Mild to moderate chest wall retractions
3. Severe
   • Marked stridor at rest
   • Severe retractions
   • Agitation or lethargy
   • Hypoxia (SpO₂ < 92%)
4. Impending respiratory failure:
   • Decreased level of consciousness
   • Fatigue
   • Cyanosis
   • Silent chest

17.6 Differential Diagnoses

Croup must be differentiated from other causes of upper airway obstruction:

Condition	Key Differences
Epiglottitis	Sudden onset, high fever, toxic appearance, drooling, “tripod” posture
Foreign body aspiration	Sudden choking episode, unilateral breath sounds
Bacterial tracheitis	High fever, purulent secretions, toxic look
Peritonsillar abscess	Older children, muffled voice, difficulty opening mouth
Retropharyngeal abscess	Neck stiffness, drooling, visible swelling on imaging

17.7 Diagnosis

Croup is primarily a clinical diagnosis, especially in resource-limited settings like many areas in Ghana.

Clinical Evaluation:

• Vital signs: look for tachypnoea, fever
• Oxygen saturation (pulse oximetry)
• General appearance: level of alertness, work of breathing

Investigations

• Neck X-ray (AP view): May reveal the classic “steeple sign” (subglottic narrowing), although it is not routinely needed.
• CBC, CRP: Not usually necessary unless bacterial superinfection is suspected.
• Nasopharyngeal swabs: Can confirm viral aetiology, but are rarely done due to cost and availability.

17.8 Management

Management depends on severity. The key principles are:

• Relieve airway obstruction
• Reduce inflammation
• Minimize agitation
• Monitor for deterioration

17.8.1 General Measures:

• Keep the child calm: Crying worsens stridor.
• Humidified air: Traditionally used, though evidence is weak.
• Supplemental oxygen: For SpO₂ < 92% or signs of hypoxia.

17.8.2 Pharmacologic Treatment

1. Corticosteroids

Mainstay of treatment, regardless of severity.

• Dexamethasone (preferred):
  • Dose: 0.15–0.6 mg/kg PO/IM/IV (max 10 mg)
  • Long half-life (~36–72 hours), a single dose is often enough
• Prednisolone (if dexamethasone unavailable):
  • Dose: 1 mg/kg/day PO for 3–5 days

Corticosteroids reduce airway inflammation, decrease hospital admissions, and shorten the duration of illness.

2. Nebulized Epinephrine (Racemic or L-epinephrine)

•  Used for moderate to severe croup:
• Dose: 0.5 mL of 2.25% racemic epinephrine or 5 mL of 1:1000 L-epinephrine via nebulizer.
• Acts quickly but temporarily (1–2 hours), often used while waiting for the corticosteroid effect.
• Observe the child for 3–4 hours after administration for any rebound symptoms.

3. Antibiotics

Not indicated unless there is a suspicion of bacterial tracheitis or a secondary infection (high fever, toxic appearance, purulent secretions).

Monitoring and Admission Criteria

Admit if:

•  Persistent stridor at rest following epinephrine
• Hypoxia (SpO₂ < 92% on room air)
• Severe work of breathing
• Inadequate oral intake
• Age under 6 months
• Pre-existing comorbidities (e.g., sickle cell disease, malnutrition)

In Ghana, admission should also be considered if reliable follow-up is uncertain, especially in rural or underserved areas.

17.9 Complications

• Respiratory failure
• Secondary bacterial tracheitis
• Dehydration
• Rarely, death (usually in severe, untreated cases)

17.10 Prevention

• Routine immunization: Influenza and measles vaccines reduce incidence
• Hand hygiene and cough etiquette
• Avoid exposure to sick contacts, especially during viral seasons

17.11 Public Health Considerations in Ghana

• Limited access to nebulizers or corticosteroids in rural facilities may delay treatment.
• Overcrowding and poor ventilation increase the transmission of respiratory viruses.
• Training community health workers in the recognition and referral of severecases is crucial.
• Integration of Integrated Management of Childhood Illness (IMCI) strategies can help guide early treatment at the primary care level.

17.12 Conclusion

Croup is a common, self-limiting pediatric illness that can become life-threatening without prompt recognition and management. Medical students and practitioners in Ghana should be proficient in diagnosing croup based on clinical features and effectively managing it with corticosteroids and supportive care. Knowing when to escalate care is crucial, particularly in resource-constrained settings.