A 2-year-old boy is brought to the emergency department by his babysitter due to noisy breathing. The patient has had rhinorrhea, congestion, and a cough for 2 days. The cough worsened last night when he developed a high-pitched noise during inspiration that worsens when he cries. Earlier today, the patient was playing in the same room as his 6-year-old brother, who also has cold symptoms. He has no chronic medical conditions. The babysitter is unsure of the patient's immunization status. Temperature is 38 C (100.4 F), pulse is 140/min, and respirations are 44/min. Pulse oximetry is 96% on room air. On examination, the patient is alert with mild suprasternal retractions and a harsh, dry cough. The pharynx is mildly erythematous without tonsillar enlargement or asymmetry. The lungs are clear on auscultation. Which of the following is the most likely diagnosis?
Key respiratory tract infections in children | ||
Diagnosis | Classic pathogen | Presentation |
Laryngotracheitis (croup) |
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Epiglottitis |
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Bronchiolitis |
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Croup (laryngotracheitis), a viral upper respiratory illness most commonly caused by parainfluenza virus, typically presents in children age 6 months to 3 years. The illness usually begins with nonspecific upper respiratory symptoms (eg, rhinorrhea, congestion) with subsequent development of fever, hoarseness, stridor (ie, high-pitched noise), and a harsh, barking, seal-like cough. The stridor worsens with agitation (eg, crying) or excitement and is typically inspiratory due to upper airway edema, but it may be biphasic (inspiratory and expiratory) in severe cases.
Croup is generally a clinical diagnosis. If the diagnosis is unclear, radiographs will reveal subglottic edema known as the steeple sign. Treatment is aimed at reducing subglottic edema. Corticosteroids (eg, dexamethasone) are useful for mild cases (eg, stridor with agitation), and nebulized racemic epinephrine is added for severe cases (ie, stridor at rest).
(Choices A and D) Bacterial tracheitis and epiglottitis are rare, severe upper airway infections classically caused by Staphylococcus aureus and Haemophilus influenzae type b, respectively. Patients typically appear ill and have an acute onset of high fever, stridor, and significant respiratory distress. Patients with epiglottitis are often unvaccinated and may assume a tripod position (leaning forward with hands on knees and neck hyperextended) to open the upper airway. This patient's gradual symptom onset, low-grade fever, and mild distress are more consistent with croup.
(Choice B) Bronchiolitis is a lower respiratory tract illness most commonly caused by respiratory syncytial virus. Patients have fever, respiratory distress, and wheezing, not inspiratory stridor.
(Choice E) Foreign body aspiration often presents after a choking episode with sudden-onset respiratory distress or stridor. This patient's stridor began before he started playing with his brother and occurred in the setting of fever and upper respiratory symptoms, making foreign body aspiration less likely than croup.
(Choice F) Laryngomalacia, caused by the collapse of supraglottic structures during inspiration, presents with chronic inspiratory stridor that begins in the neonatal period and is worse in the supine position. This otherwise healthy child has acute upper respiratory symptoms consistent with croup.
Educational objective:
Croup is a viral illness most commonly caused by parainfluenza virus. It presents with fever, hoarseness, inspiratory stridor, and a harsh, barking, seal-like cough.