17.3 Pediatric Respiratory Emergencies: Croup, Epiglottitis & Laryngospasm
Key Takeaways
- Laryngotracheobronchitis (Croup) is a viral infection (Parainfluenza type 1) in children aged 6 months to 3 years presenting with low-grade fever, inspiratory stridor, and a barking seal cough; AP neck X-ray demonstrates subglottic narrowing (the 'Steeple sign'), treated with Dexamethasone (0.6 mg/kg) and nebulized Racemic Epinephrine (0.5 mL of 2.25% solution) with a mandatory 2 to 4-hour observation period for rebound edema.
- Acute Epiglottitis is a rapidly progressive, life-threatening bacterial cellulitis (Haemophilus influenzae type B, Strep pyogenes) in children aged 2 to 7 years presenting with high fever, toxic appearance, and the '4 Ds' (Drooling, Dysphagia, Dysphonia, Distress) in a tripod position; lateral neck X-ray reveals the supraglottic 'Thumbprint sign'.
- Suspected Acute Epiglottitis is a critical emergency requiring immediate transfer to the operating room without prior distressing interventions (no oral exams, blood draws, or IV starts); inhalational induction with Sevoflurane in 100% O₂ is performed in the sitting position with spontaneous ventilation maintained while an ENT surgeon stands scrubbed for emergent tracheostomy/bronchoscopy.
- Foreign body aspiration occurs most commonly in children aged 1 to 3 years with lodgment predominantly in the right mainstem bronchus; extraction requires rigid optical bronchoscopy under deep inhalational anesthesia with preservation of spontaneous ventilation to avoid positive pressure forcing the foreign body into distal subsegmental bronchi.
- Pediatric laryngospasm is a hyperactive adductor reflex mediated by the superior (afferent) and recurrent (efferent) laryngeal nerves; management follows a strict escalation: 100% O₂ with tight mask seal, continuous positive airway pressure (CPAP 15-20 cmH₂O), Larson's notch pressure, Propofol (0.5-1.0 mg/kg IV), and Succinylcholine (0.5-1.0 mg/kg IV or 3-4 mg/kg IM) paired with Atropine (0.02 mg/kg, min 0.1 mg) to prevent severe vagal bradycardia.
Last updated: August 2026
17.3 Pediatric Respiratory Emergencies: Croup, Epiglottitis & Laryngospasm
Pediatric upper airway emergencies are among the most high-stakes crises encountered by anesthesia providers. Because airway resistance in infants and children is inversely proportional to the fourth power of the luminal radius ($R \propto 1/r^4$), even a single millimeter of circumferential mucosal edema reduces the airway cross-sectional area by up to $75%$ and increases airflow resistance 16-fold. Rapid clinical discrimination between infectious supraglottic versus subglottic pathologies and decisive execution of emergency protocols are life-saving skills.
1. Upper Airway Obstruction: Croup vs. Epiglottitis
Differentiating Laryngotracheobronchitis (Croup) from Acute Epiglottitis is a core NBCRNA exam topic and an essential clinical competency.
+---------------------------------------------------------------------------------------------------------+
| CROUP VS. EPIGLOTTITIS VS. BACTERIAL TRACHEITIS |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| Feature | Laryngotracheobronchitis | Acute Epiglottitis | Bacterial |
| | (Croup) | | Tracheitis |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Etiology** | • Viral (**Parainfluenza | • Bacterial (**Haemophilus | • Bacterial |
| | type 1**, RSV, Adenovirus)| influenzae type B**, | (**Staphylococcus |
| | | Strep, Staph aureus) | aureus**, Strep) |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Typical Age** | • **6 months to 3 years** | • **2 to 7 years** | • 1 to 6 years |
| | | (also occurs in adults) | |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Onset & Speed** | • Gradual (1 - 3 day viral | • **Abrupt, fulminant** | • Intermediate |
| | prodrome / rhinorrhea) | (hours, rapid exhaustion) | (secondary compl.)|
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Fever & Toxicity** | • Low-grade fever (<38.5°C) | • **High fever (>39.0°C)** | • High fever |
| | • Non-toxic appearance | • **Toxic, pale, lethargic**| • Toxic, ill |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Clinical Signs** | • **"Barking seal" cough** | • **The "4 Ds":** | • Croup-like bark |
| | • Hoarseness | 1. **Drooling** | with copious, |
| | • Inspiratory stridor | 2. **Dysphagia** | thick, purulent |
| | • Prefers lying or sitting | 3. **Dysphonia** ("hot | tracheal secre- |
| | | potato voice") | tions; non- |
| | | 4. **Distress** (Tripod) | responsive to |
| | | • **ABSENCE of cough** | racemic epi |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Anatomical Site** | • **Subglottic area** | • **Supraglottic area** | • Subglottic lumen |
| | (cricoid cartilage level) | (epiglottis, aryepiglottic| and tracheal |
| | | folds, false cords) | mucosa |
+-----------------------+-----------------------------+-----------------------------+---------------------+
| **Radiographic Sign** | • **"Steeple sign"** | • **"Thumbprint sign"** | • Subglottic |
| | (subglottic funneling | (swollen, enlarged | irregularity / |
| | on AP neck view) | epiglottis on lateral view| pseudomembranes |
+-----------------------+-----------------------------+-----------------------------+---------------------+
[RADIOGRAPHIC AIRWAY PATHOLOGY SCHEMATIC]
CROUP: AP NECK VIEW EPIGLOTTITIS: LATERAL NECK VIEW
[Normal Glottis] [Base of Tongue]
| | |
\ / <--- Subglottic v
\ / Mucosal Edema ( THUMBPRINT )
|| ( SIGN )
|| <--- "STEEPLE SIGN" (Swollen Epiglottis)
|| (Pencil Tip) |
/ \ v
/ \ [Obstructed Larynx]
[Trachea] |
2. Emergency Anesthetic Management of Acute Epiglottitis
Acute Epiglottitis is a true surgical airway emergency. The fundamental objective is establishing an artificial airway before total, irreversible supraglottic obstruction occurs.
The "Do Not Agitate" Golden Rule
- Zero Distress Protocol: Any agitation, crying, or pain stimulates sympathetic outflow, increases inspiratory airflow velocity, creates extreme negative dynamic airway pressures, and precipitates immediate, complete laryngospasm or mechanical soft tissue occlusion.
- Strict Mandates in the Emergency Department:
- Do NOT examine the oral cavity or pharynx with a tongue depressor.
- Do NOT attempt intravenous cannulation or blood sampling.
- Do NOT separate the child from the parent.
- Do NOT force the child to lie supine (maintain tripod/sniffing posture).
- Do NOT send the child to radiology unmonitored; transport immediately to the Operating Room.
Operating Room Induction & Intubation Protocol
- Personnel & Readiness: The Operating Room must be prepared before patient arrival. An ENT surgeon must be present in the room, scrubbed, gowned, with sterile instruments open for an immediate emergent surgical tracheostomy or rigid optical bronchoscopy.
- Inhalational Induction:
- Place the child on the operating table in the sitting position (or resting against the parent).
- Administer $100% \text{ O}_2$ with gentle blow-by, followed by gradual escalation of Sevoflurane up to $8%$.
- MAINTAIN SPONTANEOUS VENTILATION AT ALL TIMES: Under no circumstances should neuromuscular blocking agents (paralytics) or aggressive positive-pressure ventilation be administered before the airway is secured. Loss of upper airway pharyngeal muscle tone causes the massive, edematous epiglottis to fall like a ball-valve directly into the glottic aperture, creating complete, insurmountable airway obstruction.
- Intravenous Access & Atropine: Once a deep plane of surgical anesthesia (Stage III) is achieved, establish peripheral IV access and administer Atropine $0.02 \text{ mg/kg}$ IV (minimum $0.1 \text{ mg}$) to prevent vagal bradycardia and dry secretions.
- Direct / Video Laryngoscopy & Intubation:
- Perform gentle laryngoscopy. The epiglottis will appear as an amorphous, cherry-red, swollen mass obliterating normal anatomical landmarks.
- Select an endotracheal tube $0.5 - 1.0 \text{ mm}$ smaller in internal diameter than predicted for the child's age to pass through the swollen glottic inlet.
- Advance a styletted ETT or bougie through the small posterior slit between the swollen arytenoid cartilages.
- Secure the tube meticulously and transfer the intubated patient directly to the Pediatric ICU. Antibiotic therapy (third-generation cephalosporin such as Ceftriaxone) is initiated, and extubation is considered after 24 to 72 hours once a significant cuff leak is verified.
3. Medical Management of Croup & Racemic Epinephrine Pharmacology
Laryngotracheobronchitis is managed medically based on severity scoring (Westley Croup Score).
+---------------------------------------------------------------------------------------------------------+
| PHARMACOLOGIC MANAGEMENT OF CROUP |
+---------------------+-------------------+---------------------+-----------------------------------------+
| Drug & Formulation | Standard Dose | Route & Timing | Mechanism & Critical Nuances |
+---------------------+-------------------+---------------------+-----------------------------------------+
| **Dexamethasone** | **0.6 mg/kg** | **PO / IM / IV** | • Long-acting corticosteroid |
| | (Max 16 mg) | (Single dose upon | • Reduces laryngeal mucosal edema and |
| | | presentation) | vascular capillary permeability |
| | | | • Onset: 1 - 2 hours; duration: 72 hrs |
+---------------------+-------------------+---------------------+-----------------------------------------+
| **Racemic** | **0.5 mL of** | **Nebulized in** | • 1:1 mixture of D- and L-isomers |
| **Epinephrine** | **2.25% solution**| **3.0 mL NS** | • **α₁-agonist precapillary vasoconstr.**|
| | | | • Rapid onset (<10 min); duration ~2 hrs|
| | | | • **MANDATORY 2 - 4 HR OBSERVATION** |
+---------------------+-------------------+---------------------+-----------------------------------------+
Racemic Epinephrine: The Rebound Phenomenon
- Mechanism: Racemic epinephrine is a $1:1$ equimolar mixture of the dextrorotatory ($D$) and levorotatory ($L$) isomers of epinephrine. The active $L$-isomer stimulates $\alpha_1$-adrenergic receptors on subglottic mucosal arterioles, producing intense precapillary vasoconstriction, rapid fluid reabsorption, and dramatic shrinkage of subglottic mucosal edema.
- The Rebound Danger: As the vasoconstrictive effect of epinephrine dissipates (typically after $1.5 - 2 \text{ hours}$), reactive capillary vasodilation can cause rebound mucosal edema, returning the child to severe stridor and respiratory failure. Therefore, any child receiving nebulized racemic epinephrine must be closely monitored in a healthcare facility for a minimum of 2 to 4 hours before safe discharge can be considered.
4. Foreign Body Aspiration (FBA)
Foreign body aspiration represents a leading cause of accidental pediatric mortality, with peak incidence in toddlers aged 1 to 3 years.
+---------------------------------------------------------------------------------------------------------+
| FOREIGN BODY ASPIRATION CLINICAL PROFILE |
+---------------------+-----------------------------------------------------------------------------------+
| Clinical Domain | Specific Characteristics & Diagnostic Findings |
+---------------------+-----------------------------------------------------------------------------------+
| **Classic Triad** | 1. Sudden onset of violent choking / coughing |
| | 2. Unilateral wheezing or asymmetric breath sounds |
| | 3. Unilateral diminished air entry / tachypnea |
+---------------------+-----------------------------------------------------------------------------------+
| **Anatomical Site** | • **Right mainstem bronchus** (>55-60% of cases) due to wider diameter, |
| | more vertical trajectory, and greater airflow volume compared to left mainstem. |
+---------------------+-----------------------------------------------------------------------------------+
| **Radiographic** | • **Inspiratory / Expiratory Chest X-ray:** Unilateral air trapping, mediastinal |
| **Findings** | shift *away* from the affected lung on expiration ("ball-valve" air trapping). |
| | • Organic foreign bodies (peanuts, carrots) are radiolucent; metal is radiopaque. |
+---------------------+-----------------------------------------------------------------------------------+
| **Anesthetic Plan** | • **Rigid optical bronchoscopy** is the gold standard for foreign body retrieval. |
| | • Inhalation induction with Sevoflurane; **MAINTAIN SPONTANEOUS VENTILATION**. |
| | • **Avoid positive-pressure ventilation** (forces object into distal bronchi). |
+---------------------+-----------------------------------------------------------------------------------+
5. Post-Extubation Croup (Subglottic Edema)
Post-extubation croup results from mechanical pressure induced by an endotracheal tube against the non-expansile cricoid cartilage ring.
- Risk Factors: (1) Age $<4$ years, (2) Oversized ETT (absence of leak at $>25 \text{ cmH}_2\text{O}$), (3) Prolonged intubation ($>1 \text{ hour}$), (4) Head and neck repositioning or prone positioning, (5) Repeated intubation attempts, (6) Excessive coughing/bucking on the ETT.
- Management: Humidified oxygen, IV Dexamethasone ($0.5 - 1.0 \text{ mg/kg}$), and nebulized Racemic Epinephrine ($0.5 \text{ mL}$ of $2.25%$ solution).
6. Pediatric Laryngospasm: Crisis Escalation Protocol
Laryngospasm is defined as an involuntary, sustained closure of the vocal cords (true cords, false cords, and aryepiglottic folds) mediated by intrinsic laryngeal adductor muscle contraction.
[NEUROANATOMY OF LARYNGOSPASM]
[Sensory Stimulus (Blood, Secretions, Light Plane)]
|
v
**Internal Branch of Superior Laryngeal Nerve (SLN)**
(Sensory Afferent)
|
v
[Medullary Brainstem Nuclei]
|
v
**Recurrent Laryngeal Nerve (RLN)**
(Motor Efferent)
|
v
[Intrinsic Laryngeal Adductor Muscle Contraction]
• Lateral Cricoarytenoid
• Transverse / Oblique Arytenoids
• Thyroarytenoid
|
v
**COMPLETE AIRWAY OCCLUSION**
Step-by-Step Crisis Protocol for Laryngospasm
+---------------------------------------------------------------------------------------------------------+
| LARYNGOSPASM CRISIS ESCALATION PROTOCOL |
+------------------+----------------------------------+---------------------------------------------------+
| Step | Action / Intervention | Clinical Technique & Pharmacology |
+------------------+----------------------------------+---------------------------------------------------+
| **Step 1:** | • Remove stimulus | • Suction pharynx, stop surgical stimulation |
| **Oxygenation** | • **100% Oxygen** | • Apply two-hand tight mask seal |
+------------------+----------------------------------+---------------------------------------------------+
| **Step 2:** | • **Continuous Positive Airway** | • Close APL valve to **15 - 20 cmH₂O** |
| **CPAP** | ** Pressure (CPAP)** | • Pneumatically splints laryngeal inlet open |
+------------------+----------------------------------+---------------------------------------------------+
| **Step 3:** | • **Larson's Maneuver** | • Apply forceful inward and anterior pressure |
| **Larson Notch** | ** (Laryngospasm Notch)** | bilaterally behind condyle of mandible / |
| | | anterior to mastoid process with jaw thrust |
+------------------+----------------------------------+---------------------------------------------------+
| **Step 4:** | • **Propofol Bolus** | • Administer **0.5 - 1.0 mg/kg IV** |
| **Deepen Plane** | | • Relaxes laryngeal musculature in mild spasm |
+------------------+----------------------------------+---------------------------------------------------+
| **Step 5:** | • **Succinylcholine & Atropine** | • **IV:** Succinylcholine **0.5 - 1.0 mg/kg IV** |
| **Paralysis** | (Neuromuscular Blockade) | (or 2.0 mg/kg IV if re-intubating) |
| | | • **IM:** Succinylcholine **3.0 - 4.0 mg/kg IM** |
| | | (deltoid or intralingual) if no IV access |
| | | • **Atropine 0.02 mg/kg IV/IM** (min 0.1 mg) |
| | | MANDATORY to prevent severe vagal asystole! |
+------------------+----------------------------------+---------------------------------------------------+
[LARSON'S LARYNGOSPASM NOTCH ANATOMY]
[Ear Canal]
|
[Mastoid] **NOTCH** [Ramus of Mandible]
[Process] | [Angle of Jaw]
\ v /
\ **FORCEFUL INWARD** /
\ **& ANTERIOR PUSH**/
\===================/
• Stimulates Trigeminal / Glossopharyngeal Reflex
• Distracts Hyoid & Mandible Anteriorly
• Breaks Intrinsic Adductor Spasm
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Test Your Knowledge
A 3-year-old child presents to the emergency department with a 2-hour history of high fever (39.8°C), severe inspiratory stridor, drooling, difficulty swallowing, and sitting upright in a tripod position. Lateral neck radiography confirms an enlarged, swollen epiglottis ('thumbprint sign'). What is the most appropriate management plan?
A
B
C
D
Test Your Knowledge
A 2-year-old child with moderate croup receives nebulized racemic epinephrine (0.5 mL of 2.25% solution in 3 mL normal saline) in the urgent care clinic. Within 15 minutes, the child's inspiratory stridor and work of breathing resolve completely. Why must this patient be monitored in the clinical facility for at least 2 to 4 hours following treatment?
A
B
C
D
Test Your Knowledge
A 14-month-old toddler is suspected of aspirating a small piece of a plastic toy into the tracheobronchial tree. Which anatomical location is the most frequent site of foreign body lodgment, and what is the primary anesthetic consideration during rigid bronchoscopy?
A
B
C
D
Test Your Knowledge
Immediately following extubation after an adenoidectomy, a 4-year-old child develops complete laryngospasm with silent chest movement, absent ETCO₂ waveform, severe sternal retractions, and rapid desaturation to SpO₂ 72%. No peripheral IV line is available. What is the most definitive emergency pharmacologic intervention?
A
B
C
D