🫁 Chapter 3: Respiratory Distress

Nelson's Pediatric Symptom-Based Diagnosis | Tachypnea · Stridor · Wheezing · Asthma · Croup · Epiglottitis · Bronchiolitis · Respiratory Failure

🔍 Respiratory Distress in Children: Key Concepts

📊 Definitions & Signs
Tachypnea: RR >50 (2-12mo), >40 (1-5y), >30 (>5y). Signs: nasal flaring, retractions (intercostal, subcostal, suprasternal), grunting, head bobbing, cyanosis, altered mental status.
🔄 Stridor (Upper Airway)
Inspiratory → supraglottic/glottic (croup, laryngomalacia). Biphasic → fixed subglottic/tracheal (foreign body, stenosis). Expiratory → intrathoracic tracheal lesion.
⚠️ Wheezing (Lower Airway)
Expiratory musical sound: asthma (most common), bronchiolitis (RSV), foreign body, anaphylaxis, vocal cord dysfunction. Unilateral wheeze → foreign body until proven otherwise.
💧 Asthma Exacerbation
Severity: mild (talks in sentences, PEF ≥70%), moderate (phrases, PEF 40-69%), severe (words, PEF <40%), impending arrest (silent chest, bradycardia). Tx: SABA + systemic corticosteroids + O2.
🧬 Croup vs Epiglottitis
Croup: viral, barking cough, gradual, dexamethasone + racemic epinephrine. Epiglottitis: bacterial (Hib), toxic, drooling, tripod, thumb sign on X-ray, airway emergency.
🚩 Red Flags for Impending Failure
Silent chest, decreased breath sounds, bradycardia, cyanosis despite O2, altered consciousness, fatigue, PaCO2 >50 mmHg, hypoxemia unresponsive to oxygen.

💡 Key Takeaway: Rapid recognition of respiratory distress patterns (stridor vs wheeze vs tachypnea) guides diagnosis. Secure airway first. Differentiate croup vs epiglottitis; never examine oropharynx if epiglottitis suspected. Asthma treatment escalates from bronchodilators to steroids to ICU for impending failure.

🩺 Clinical Approach to Respiratory Distress: Step-by-Step Algorithm

🔹 Step 1: Immediate assessment (ABC)
• Airway: stridor, drooling, aphonia → suspect upper airway obstruction (epiglottitis, FB, angioedema).
• Breathing: tachypnea, retractions, wheezing, grunting, SaO2.
• Circulation: heart rate, blood pressure, perfusion.
🔹 Step 2: Localize obstruction by sound & timing
• Inspiratory stridor → extrathoracic (croup, laryngomalacia, epiglottitis).
• Expiratory wheeze → intrathoracic (asthma, bronchiolitis, foreign body).
• Grunting → parenchymal disease (pneumonia, pulmonary edema).
🔹 Step 3: Red flags requiring emergency intervention
• Stridor at rest, drooling, toxic appearance → epiglottitis (DO NOT examine throat; immediate OR for airway).
• Sudden onset choking + unilateral wheeze → foreign body aspiration → bronchoscopy.
• Altered mental status, fatigue, silent chest → impending respiratory failure.
🔹 Step 4: Diagnostic tools
• Pulse oximetry, blood gas if severe.
• Lateral neck X-ray (epiglottitis: thumb sign; croup: steeple sign; retropharyngeal abscess: widened prevertebral space).
• Chest X-ray (hyperinflation, infiltrate, FB, pneumothorax).
• Spirometry for asthma (children >5y).
🔹 Step 5: Management by etiology
• Croup: dexamethasone 0.6 mg/kg (oral/IM/IV); racemic epinephrine for moderate-severe.
• Asthma: albuterol + ipratropium + systemic steroids; MgSO4 or terbutaline for severe.
• Epiglottitis: secure airway (intubation), IV ceftriaxone.
• Bronchiolitis: supportive, nasal suction, O2; no steroids or bronchodilators routinely.
• Foreign body: rigid bronchoscopy for removal.