Clinical Presentation

A 2-year-old presents with a sudden onset of barky cough and inspiratory stridor in the middle of the night.

Figure 29A

Radiologic Findings

Croup

Differential Diagnosis

• Post-intubation subglottic inflammation/fibrosis
  
• Subglottic masses such as hemangioma
  
• Subglottic mucocele
  
• Glottic or subglottic foreign body
  
• Bacterial tracheitis

Discussion

Background

Croup is the most common cause of acquired upper respiratory obstruction in children. It is characterized by subglottic inflammation caused by an acute viral infection, most commonly from a parainfluenza infection. Many upper respiratory acute viral pathogens can produce a similar picture.

Clinical Findings

Croup is most commonly seen in the winter months, when parainfluenza and influenza viruses are most active. Characteristically, the child develops inspiratory stridor and intercostal retractions. The symptoms are frequently worse at night, improve with exposure to cool outside air, and commonly present in association with a nonspecific upper respiratory tract infection. Physics principles dictate that airway resistance is inversely proportional to the radius of the airway (1/R⁴