**Laryngotracheobronchitis** **Definition:** * Inflammation of the larynx, trachea, and bronchi. * Also known as croup. * Viral infection is the usual cause. **Clinical Features:** * **Symptoms:** * Barking cough (seal-like cough) * Stridor * Hoarseness * Difficulty breathing * Fever * Rhinorrhea * Pharyngitis * **Signs:** * Suprasternal and intercostal retractions * Tachypnea * Tachycardia * Decreased oxygen saturation **Classification:** * **Mild:** Barking cough, stridor, mild respiratory distress * **Moderate:** Increased respiratory distress, retractions, tachypnea, tachycardia * **Severe:** Severe respiratory distress, cyanosis, altered mental status **Management:** * **Mild disease:** * Supportive care at home * Increased fluids * Humidified air * Acetaminophen or ibuprofen for fever * **Moderate disease:** * Hospitalization * Close monitoring * Oxygen therapy * Nebulized racemic epinephrine * Corticosteroids * **Severe disease:** * Intubation and mechanical ventilation **Diagnosis:** * **Clinical diagnosis** is usually sufficient. * **Imaging:** * Chest X-ray: Steeple sign * CT scan: Subglottic narrowing * **Laboratory tests:** * CBC: Elevated WBC count * Blood gas: Hypoxemia * Viral PCR: To identify the virus **Complications:** * **Respiratory failure** * **Pneumonia** * **Cardiac arrest** **Other:** * **Soft tissue infections:** Epiglottitis, bacterial tracheitis * **Foreign body aspiration** **Additional Notes:** * **Viral causes:** Parainfluenza virus, RSV, influenza, adenovirus * **Bacterial causes:** Less common, usually in children with underlying conditions * **Risk factors:** Age (6 months to 3 years), male sex, exposure to smoke * **Prevention:** Vaccination against influenza and RSV * **Prognosis:** Most children recover fully. **Note:** The handwritten text is sometimes difficult to read and may have minor inaccuracies.