Epiglottitis

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

Epiglottitis is characterized by acute, rapidly progressive inflammation and marked edema of the epiglottis and its adjacent supraglottic structures (including the aryepiglottic folds and arytenoids).

## Supraglottic Compression Cascade
│
[ Bacterial Infiltration ]
(S. pneumoniae, GAS, or S. aureus)
│
▼
[ Acute Vascular Congestion ]
(Rapid Fluid Transudation into Lax
Submucosal Supraglottic Tissue)
│
▼
[ Progressive Edema Space ]
(Strictly confined to structures above
the tightly bound Vocal Cords)
│
▼
[ Mechanical Downward & Posterior Folding ]
(Epithelial swelling forces the Epiglottis
posteriorly, sealing the laryngeal inlet)
│
▼
[ Complete Obstruction ]

• Microbial Shift & Tissue Tropism: Historically a classic pediatric disease driven by Haemophilus influenzae type b (Hib), the post-vaccination era has shifted the epidemiologic peak to adults (mean age 45 years). Pathogenesis is now primarily driven by Streptococcus pneumoniae, Group A Streptococcus, and Staphylococcus aureus. The primary infection targets the lax, vascular submucosa of the lingual surface of the epiglottis, where loose connective tissue allows massive, unhindered transudation of fluid and cellular infiltration.
• Mechanical Airway Blockade: Because the squamous epithelium is tightly bound to the perichondrium on the laryngeal surface but loosely attached on the lingual aspect, swelling occurs preferentially backward and downward. The highly edematous, heavy epiglottis is pushed posteriorly by inspiratory airflow (the Venturi effect), folding over the laryngeal inlet and acting as a physical one-way valve that seals the airway.
• Anatomic Vulnerability in Pediatrics: Children are at an exceptionally high risk of rapid, catastrophic airway occlusion. Their smaller baseline laryngeal diameter means that even a minor absolute increase in mucosal thickness exponentially increases airway resistance (Poiseuille’s Law: resistance is inversely proportional to the radius to the fourth power, \(R \propto 1/r^4\)). Furthermore, the pediatric epiglottis is more compliant and omega-shaped, making it highly susceptible to collapsing inward under negative inspiratory pressures.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

Immediate Triage and Bedside Stabilization

1. High-Visibility Stabilization: Immediately place the patient in a high-visibility resuscitation bay. Ensure continuous cardiorespiratory monitoring, pulse oximetry, and establish reliable intravenous access.
2. Strict Positioning: Never force the patient to lie flat. Keep the patient strictly in a sitting-upright, comfortable position (usually tripod or sniffing position) to optimize airway patency.
3. Minimize Noxious Stimuli: Keep the patient as calm as possible. Avoid painful or anxiety-provoking procedures (such as aggressive IV attempts or laboratory blood draws) if they distress the patient, as agitation can trigger immediate laryngospasm and complete airway closure.
4. Oxygenation: Provide gentle, humidified supplemental oxygen. Humidification prevents desiccation of secretions and minimizes the risk of sudden airway blockage.

Controlled Airway Management Protocol

• The Gold Standard (Operating Room): If the airway is currently patent but there is a high risk of obstruction, immediately consult Otolaryngology (ENT) and Anesthesiology. The preferred strategy is to transport the patient with a physician escort to the operating room (OR) for controlled intubation under general anesthesia with a dual set-up fully prepared for an emergent surgical airway.
• Emergency Department Intubation Sequence: If the patient exhibits signs of impending respiratory arrest (severe stridor, drooling, progressive hypoxia, or inability to handle secretions) and transport is impossible, perform awake fiberoptic intubation.
• Avoid Neuromuscular Blockade (Paralytics): Standard rapid sequence induction (RSI) is contraindicated. Relaxing the accessory muscles of respiration under paralysis will cause immediate collapse of the edematous supraglottic tissues, resulting in a catastrophic "cannot intubate, cannot ventilate" scenario.
• Contraindicated Devices: Do not use supraglottic airway devices (such as LMAs). These devices can fold or flatten the swollen epiglottis further down over the glottic opening, worsening the obstruction.
• Surgical Airway Readiness: Mark the cricothyroid membrane before any intubation attempts are made. Have a surgical cricothyroidotomy kit open at the bedside.

Acute Medical Pharmacotherapy

• Empiric Parenteral Antibiotic Therapy (Initiate immediately after securing the airway or if the patient is stable and non-distressed):
• First-line: Ceftriaxone 2 g IV once daily (Pediatric: 50 mg/kg IV once daily) OR Ampicillin/sulbactam 3 g IV every 6 hours (Pediatric: 50 mg/kg of the ampicillin component IV every 6 hours).
• Alternative for Penicillin-Allergic Patients: Levofloxacin 750 mg IV once daily.
• Corticosteroid Administration (To reduce supraglottic edema and decrease the need for mechanical airway intervention):
• Dexamethasone 0.6 mg/kg IV up to a maximum dose of 10 mg OR Methylprednisolone 125 mg IV.
• Temporizing Adjuvant Therapy (Adults Only):
• Nebulized 2.25% Racemic Epinephrine: Administer 0.5 mL of 2.25% solution diluted in 3 mL of normal saline via a jet nebulizer every 3 to 4 hours.
• Critical Pediatric Restriction: Nebulized racemic epinephrine is not recommended for pediatric patients with epiglottitis. The associated systemic sympathetic effects (tachycardia, agitation, and anxiety) can increase respiratory effort and trigger acute, complete airway obstruction.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Critical "Can't-Miss" Airway Differentials

1. Retropharyngeal / Parapharyngeal Abscess: Deep neck space infection presenting with severe throat pain, fever, and dysphagia. Differentiated by the presence of marked trismus, asymmetrical palatal swelling, and posterior pharyngeal wall bulging.
2. Bacterial Tracheitis: A severe, invasive bacterial infection of the subglottic trachea. Differentiated by thick, copious, purulent tracheal secretions, high fevers, and a toxic appearance, typically following a mild croup-like prodrome.
3. Croup (Laryngotracheobronchitis): Viral subglottic inflammation. Differentiated by a characteristic loud, barking "seal-like" cough, a slower onset, and a non-toxic appearance in a child who does not drool and prefers to lie flat.
4. Angioedema (Anaphylactic or Drug-Induced): Rapidly progressive non-inflammatory swelling of the lips, tongue, and supraglottis. Differentiated by an abrupt onset following allergen exposure or ACE-inhibitor use, and the absence of fever, infectious symptoms, or odynophagia.
5. Oropharyngeal Foreign Body / Caustic Ingestion: Direct physical or chemical mucosal injury. Differentiated by a sudden onset of symptoms during eating or unsupervised play, with visible oral burns or an acute history of choking.

Prioritized Workup Strategy

• Step 1: Clinical Diagnosis Overrides Testing: If the patient exhibits clear red flags of airway compromise (drooling, tripod positioning, stridor), epiglottitis is a clinical diagnosis; do not delay airway management or patient stabilization for laboratory tests or imaging.
• Step 2: Restricted Out-of-Department Imaging: A patient with any concern for airway compromise must never leave the ED patient care area for imaging. If a lateral neck radiograph is desired, it must be performed as a bedside portable study with a physician skilled in difficult airway management present.
• Step 3: Laboratory Evaluation (Deferred Until Secure):
• Do not draw labs if the needle stick will cause patient distress or crying.
• Once the airway is secured, obtain two sets of blood cultures.
• In intubated patients, obtain direct epiglottic cultures to guide antibiotic tailoring.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

Portable Lateral Soft Tissue Neck Radiograph

## Portable Lateral Soft Tissue View
│
┌───────────────────┴───────────────────┐
▼                                       ▼
[ Swollen Epiglottis ]                 [ Aryepiglottic Folds ]
│                                       │
▼                                       ▼
[ Classic "Thumbprint" ]              [ Markedly Thickened ]
(Replaces thin,                       (Obliterates normal
normal "finger-like"                     vallecular space)
epiglottis outline)

A lateral soft tissue neck X-ray demonstrating a swollen epiglottis resembling a "thumb" (the thumbprint sign) paired with thickened aryepiglottic folds is highly concerning for epiglottitis. Visualization of a clear, open vallecular space is reassuring. Crucially, a negative lateral X-ray does not exclude the diagnosis.

Bedside Point-of-Care Ultrasound (POCUS) Airway Checklist

Using a high-frequency linear transducer placed transversely on the neck just below the hyoid bone, evaluate for the following objective sonographic markers of epiglottitis:

• Anterior-Posterior (AP) Diameter Cutoff: Measure the AP diameter of the epiglottis. An AP diameter >3.6 mm is highly sensitive and specific for acute epiglottitis.
• The "Alphabet P" Sign: Scan in the midsagittal plane. The Alphabet P sign is created by the distinct acoustic shadow cast by the hyoid bone anteriorly, paired with the hypoechoic, swollen, rounded epiglottis immediately posterior to it (resembling the letter "P").

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

Risk Factors Dictating Immediate Intubation

Because there is no single validated scoring system that dictates disposition, the emergency physician must risk-stratify the patient based on the presence of clinical "red flags" that indicate a high probability of rapid, complete airway collapse:

## Risk-Stratification Matrix
│
┌──────────────────────┴──────────────────────┐
▼                                             ▼
[ High-Risk Class ]                           [ Moderate-Risk Class ]
(Immediate Intubation in OR)                     (ICU Admission, Close Watch)
│                                             │
- Drooling / Secretion Pooling           - Severe sore throat / Odynophagia
- Stridor                                - High fever (Toxic appearance)
- Sniffing / Tripod position        - Normal voice / No stridor
- Hypoxia (SpO2 <92%)               - Able to handle oral secretions
- Restricted mouth opening (<15 mm)      - Reassuring POCUS / Lateral X-ray

SMART-COP Scoring for ICU Resource Allocation

If the patient is stable and managed conservatively without immediate intubation, utilize the SMART-COP tool to predict the likelihood of requiring intensive care and vasoactive or ventilatory support:

• Systolic Blood Pressure (Hypotension ≤100 mmHg) — 2 points
• Multilobar chest infiltrates on radiograph — 1 point
• Albumin level low (<3.5 g/dL) — 1 point
• Respiratory Rate elevated (≥25/min) — 1 point
• Tachycardia (HR ≥125 bpm) — 1 point
• Confusion / Altered Mental Status — 1 point
• Oxygenation low (PaO2 <70 mmHg or SpO2 <93%) — 2 points
• PH low on arterial gas (<7.35) — 2 points
• Cutoff Guidance: A SMART-COP score ≥3 points indicates a high risk of respiratory failure or septic shock, mandating continuous ICU admission.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

Deadly Cognitive Traps & Trainee Errors

• The "Normal Oropharynx" Reassurance Trap: Assuming a patient does not have a deep throat infection because the posterior oropharynx appears completely normal. In epiglottitis, the oropharynx is classically completely clear without tonsillar hypertrophy, erythema, or exudate because the pathology is localized entirely in the supraglottis.
• The Out-of-Department Imaging Disaster: Sending a patient with suspected epiglottitis to the radiology suite for a lateral neck X-ray or CT scan. If the patient undergoes acute airway spasm or complete obstruction while isolated in a scanner or hallway, the result is frequently fatal.
• The Paralytic-Induced Collapse Pitfall: Attempting a standard rapid sequence induction (RSI) using paralytics (succinylcholine or rocuronium) in the ED. Loss of baseline skeletal muscle tone instantly eliminates the airway's structural support, causing the swollen, floppy epiglottis to fall backward and completely seal the glottis.
• The Direct ED Visualization Mistake: Attempting to visualize the epiglottis with a standard tongue depressor or performing direct laryngoscopy/flexible endoscopy in the emergency department. ED instrumentation of the supraglottis can cause immediate laryngospasm and complete airway closure.

Board-Mandated Critical Actions

• Consult ENT and Anesthesia immediately upon initial clinical suspicion.
• Never leave a patient with suspected epiglottitis unattended or allow them to lie supine.
• Contraindicate the use of supraglottic/LMA devices for rescue ventilation.
• Establish a surgical airway backup plan (cricothyroidotomy) prior to any intubation attempts.

7. MCQ MASTERCLASS (Written Exam Tips)

• "Post-Hib Epidemiologic Shift":
• High-Yield Fact: Since the widespread adoption of the Haemophilus influenzae type b (Hib) conjugate vaccine, the pediatric incidence of epiglottitis has plummeted. The mean age of presentation is now 45 years, and the primary pathogens are Streptococcus pneumoniae, Group A Streptococcus, and Staphylococcus aureus.
• "Thumbprint Sign":
• High-Yield Fact: The classic radiographic finding on a lateral soft tissue neck X-ray. Differentiate it from the "Steeple Sign" (subglottic narrowing) seen in viral croup.
• "POCUS AP Diameter >3.6 mm":
• High-Yield Fact: The definitive, quantitative bedside ultrasound measurement for epiglottitis, measured transversely just below the hyoid bone.
• "The Vagus Nerve Hiccup Link":
• High-Yield Fact: Stimulation of the vagus nerve's auricular branch (Arnold's nerve) or recurrent laryngeal branch by supraglottic inflammation can rarely present with chronic hiccups or a persistent cough.
• "Contraindicated LMAs":
• High-Yield Fact: Exam questions often list an LMA as a rescue option in a difficult epiglottitis airway. This is a red herring. LMAs are contraindicated because they directly press the swollen epiglottis down over the trachea.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

High-Yield Verbal Script for Oral Boards

Evaluating an 8-year-old female presenting with high fever, a muffled voice, drooling, and tripod positioning in the resuscitation bay:

"Examiner, I recognize this presentation as a true, life-threatening airway emergency. This patient's drooling, tripod positioning, and muffled voice indicate acute, severe epiglottitis with impending airway obstruction.

I will place this patient in a high-visibility treatment area and obtain continuous cardiorespiratory monitoring, pulse oximetry, and intravenous access, while keeping the child strictly sitting upright. To prevent catastrophic, complete airway closure driven by agitation, I will keep her as calm as possible, defer all unnecessary noxious stimuli (such as aggressive IV sticks or blood draws), and provide gentle, humidified supplemental oxygen.

I am immediately activating our difficult airway response team, mobilizing a senior Otolaryngologist and Anesthesiologist to the bedside. My primary goal is to transport the patient with physician escort directly to the operating room for controlled, awake fiberoptic intubation under general anesthesia with a dual set-up prepared for an immediate surgical airway.

If she deteriorates rapidly in the ED and cannot be safely moved, I will prepare for an emergency awake fiberoptic intubation at the bedside. I will strictly avoid neuromuscular blockade, as paralytics will cause supraglottic collapse. I will mark the cricothyroid membrane and have a surgical cricothyroidotomy kit open and ready. I will not attempt to place a supraglottic device, as this can worsen the mechanical blockage.

While preparing for airway management, I will perform a bedside POCUS of the airway to measure the AP diameter of the epiglottis, looking for a diameter greater than 3.6 mm to confirm the diagnosis. I will not allow the patient to leave the resuscitation bay for any imaging.

Once the airway is secured, I will obtain blood and epiglottic cultures. I will immediately administer parenteral antibiotics to cover Streptococcus and Staphylococcus, specifically Ceftriaxone 2 g IV and Dexamethasone 10 mg IV to reduce edema.

This patient is a mandatory intensive care unit admission for continuous airway monitoring, and under no circumstances will she be discharged from the emergency department."