ENT · Laryngotracheobronchitis
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Croup is most commonly caused by parainfluenza virus infection leading to inflammation of the larynx and trachea.
The classic clinical presentation is a barking cough and inspiratory stridor following a prodrome of upper respiratory symptoms.
An AP neck radiograph classically reveals the steeple sign, representing subglottic narrowing of the airway.
The primary treatment for all patients with croup is a single dose of dexamethasone to reduce airway edema.
Patients with stridor at rest or significant respiratory distress require the administration of nebulized racemic epinephrine.
Croup typically affects children between the ages of 6 months and 3 years.
Clinical improvement after nebulized epinephrine necessitates a period of observation to monitor for the rebound effect.
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A 14-month-old male is brought to the emergency department by his parents due to a two-day history of rhinorrhea and a low-grade fever. The parents report that the child developed a harsh, barking cough last night that sounds like a seal. On physical examination, the child is alert but exhibits inspiratory stridor at rest and mild subcostal retractions. An AP neck radiograph is obtained and demonstrates a steeple sign in the subglottic region.
What is the most appropriate next step in the management of this patient?
Nebulized racemic epinephrine and oral dexamethasone
The patient presents with moderate-to-severe croup (stridor at rest), which requires both corticosteroids for inflammation and nebulized epinephrine to provide rapid relief of airway obstruction.
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Etiology / Epidemiology
Common in 6 months to 3 years; caused by Parainfluenza virus.
Clinical Manifestations
Presents with barking cough and inspiratory stridor.
Diagnosis
Radiography shows the steeple sign.
Treatment
Dexamethasone is first-line; avoid intubation unless airway obstruction is severe.
Prognosis
Self-limiting; 95% improve with outpatient management.
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Epidemiology & Etiology
Primarily affects children aged 6 months to 3 years during late autumn and winter. The most common pathogen is Parainfluenza virus type 1. It is a viral infection of the upper respiratory tract causing subglottic inflammation.
Pertinent Anatomy
The infection targets the subglottic larynx and trachea. Because this area is the narrowest part of the pediatric airway, even minor edema causes significant airway resistance.
Pathophysiology
Viral infection leads to mucosal inflammation and edema in the subglottic space. This narrowing creates turbulent airflow, manifesting as the characteristic barking cough and inspiratory stridor. Increased work of breathing occurs as the airway diameter decreases.
Clinical Manifestations
Patients present with a sudden onset of a barking cough, inspiratory stridor, and hoarseness. Red flags include drooling, tripod positioning, or cyanosis, which suggest impending respiratory failure or epiglottitis.
Diagnosis
Diagnosis is primarily clinical. If imaging is performed, AP neck radiograph reveals the steeple sign, representing subglottic narrowing. Pulse oximetry is often normal unless the patient is in severe distress.
Treatment
Administer a single dose of Dexamethasone (0.6 mg/kg) to all patients. For moderate to severe cases, add nebulized epinephrine to reduce mucosal edema. Do not use antibiotics as the etiology is viral.
Prognosis
Most cases are mild and resolve within 3 to 7 days. Monitor for respiratory fatigue; if symptoms persist after epinephrine, hospital admission is required.
Differential Diagnosis
Epiglottitis: high fever, drooling, and toxic appearance
Bacterial tracheitis: high fever and purulent secretions
Foreign body aspiration: sudden onset without prodromal URI
Retropharyngeal abscess: neck stiffness and dysphagia
Peritonsillar abscess: uvula deviation and trismus