Overview
Definition:
Croup, also known as laryngotracheobronchitis, is an acute viral infection of the upper airway characterized by inflammation of the larynx and trachea, leading to characteristic inspiratory stridor and a barking cough.
Epidemiology:
It is the most common cause of acute upper airway obstruction in children aged 6 months to 3 years
Peak incidence occurs in autumn and early winter
Most cases are mild and resolve spontaneously.
Clinical Significance:
Severe croup can lead to significant respiratory distress and airway compromise, necessitating prompt recognition and management
Understanding appropriate pharmacological interventions, including steroid and racemic epinephrine therapy, is crucial for pediatric residents preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Characteristic barking cough, often described as sounding like a seal
Inspiratory stridor, which may worsen when the child is agitated or crying
Hoarseness
Mild fever
Symptoms typically worsen at night and may improve with exposure to cool, moist air.
Signs:
Audible stridor at rest
Retractions (suprasternal, intercostal, subcostal) indicating increased work of breathing
Tachypnea
Tachycardia
In severe cases, cyanosis and altered mental status may be present
Nasal flaring
Grunting respirations.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on the characteristic barking cough and inspiratory stridor
No specific laboratory tests are required for diagnosis
A plain radiograph of the neck may show subglottic narrowing (the "steeple sign"), but this is often absent in mild to moderate croup and not necessary for diagnosis or management decisions.
Diagnostic Approach
History Taking:
Duration of symptoms
Onset and progression of cough and stridor
Presence of fever
Exposure to sick contacts
History of previous croup or other respiratory illnesses
Pre-existing conditions like asthma
Age of the child.
Physical Examination:
Assess the severity of respiratory distress
Evaluate the degree of stridor (inspiratory vs
biphasic)
Note the presence and severity of retractions
Assess oxygen saturation
Examine for signs of dehydration
Assess the child's level of consciousness and hydration status.
Investigations:
Generally, no investigations are required for typical croup
If bacterial tracheitis is suspected, blood tests (CBC, CRP) and direct laryngoscopy may be considered
However, for uncomplicated viral croup, investigations are typically deferred.
Differential Diagnosis:
Foreign body aspiration
Bacterial tracheitis
Epiglottitis (rare with routine immunization)
Laryngeal edema
Viral laryngitis
Retropharyngeal abscess
Anaphylaxis
Allergic reactions
These conditions may present with stridor but often have differentiating features such as sudden onset (foreign body), high fever and toxic appearance (bacterial tracheitis/epiglottitis), or absent barky cough.
Management
Initial Management:
Assess the severity of respiratory distress using a validated score (e.g., Westley score)
Provide supplemental oxygen if hypoxic (SpO2 < 92%)
Keep the child calm and comfortable
avoid unnecessary procedures that may agitate the child
Humidified air (cool mist) may provide symptomatic relief.
Medical Management:
Dexamethasone: A single dose of corticosteroids is the mainstay of medical treatment to reduce airway inflammation
Dosing: 0.15 mg/kg to 0.6 mg/kg (maximum dose typically 16 mg) orally or intravenously
Intramuscular administration is also an option
Nebulized Epinephrine (Racemic Epinephrine): For moderate to severe croup with significant stridor and/or retractions
Dosing: 0.05 mL/kg of 1:1000 racemic epinephrine solution, nebulized
Repeat doses may be given every 20-30 minutes if significant improvement is seen after the initial dose and then symptoms recur
Monitor closely for rebound stridor after epinephrine wears off.
Surgical Management:
Rarely indicated for viral croup
Surgical airway intervention (e.g., intubation) is reserved for cases of severe respiratory failure refractory to medical management or with complete airway obstruction.
Supportive Care:
Encourage oral fluids if tolerated
Monitor vital signs, respiratory status, and oxygen saturation closely
Observe for a minimum of 3-4 hours after nebulized epinephrine to ensure no rebound symptoms before discharge
Provide clear discharge instructions to parents regarding warning signs.
Complications
Early Complications:
Secondary bacterial infection (bacterial tracheitis)
Pneumonia
Otitis media
Acute respiratory failure requiring intubation
In severe cases, cardiorespiratory arrest.
Late Complications:
Recurrent episodes of croup
Although less common, chronic stridor or voice changes are very rare
Long-term pulmonary sequelae are generally not associated with uncomplicated croup.
Prevention Strategies:
While viral transmission cannot be entirely prevented, good hand hygiene and avoiding close contact with individuals who have upper respiratory infections can help reduce exposure
Prompt and appropriate management of initial symptoms can prevent progression to severe disease.
Prognosis
Factors Affecting Prognosis:
Severity of initial presentation
Age of the child (younger children may have a higher risk of severe disease)
Presence of underlying comorbidities
Promptness and adequacy of medical intervention.
Outcomes:
Most cases of croup are mild and self-limiting, resolving within 3-7 days
With appropriate treatment, the vast majority of children recover fully without long-term sequelae
Severe cases requiring intubation have a good prognosis with prompt and skilled care.
Follow Up:
Children with mild croup typically do not require specific follow-up
Parents should be advised to seek immediate medical attention if symptoms worsen, breathing becomes difficult, or the child appears lethargic
For children who have required hospitalization or intubation, follow-up may be indicated to ensure complete recovery and address any potential complications.
Key Points
Exam Focus:
Understand the typical age group and seasonal pattern of croup
Differentiate croup from more serious conditions like epiglottitis and foreign body aspiration
Master the dosing of dexamethasone (0.15-0.6 mg/kg) and racemic epinephrine (0.05 mL/kg of 1:1000 solution)
Recognize indications for nebulized epinephrine and corticosteroid therapy.
Clinical Pearls:
The "steeple sign" is a helpful radiographic finding but is not always present and should not delay treatment
Keeping the child calm is paramount
agitation exacerbates stridor
Observe children closely after nebulized epinephrine for rebound symptoms before discharge.
Common Mistakes:
Delaying treatment in a child with significant respiratory distress
Over-reliance on radiographic diagnosis (steeple sign) instead of clinical assessment
Inappropriate dosing of medications, especially epinephrine
Discharging a child too early after epinephrine administration without adequate observation period.