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Summary Table

Category	Details
Risk Factors	Unvaccinated children (age 2 to 6), adults with immunocompromise, absent Hib vaccination history
Etiology	Haemophilus influenzae type b (classic pediatric); Streptococcus species, Staphylococcus aureus, non-typeable H. influenzae (adults)
Patient Presentation	Abrupt onset of high fever, severe sore throat, dysphagia, drooling, muffled voice; symptom progression over hours, not days
Classic Physical Exam	Tripod position (sitting upright, leaning forward, neck extended, chin protruding), drooling, stridor, toxic appearance, absence of spontaneous cough
Key Diagnostic Results	Lateral neck X-ray showing the thumbprint sign (swollen epiglottis); direct visualization via laryngoscopy in a controlled setting confirms the diagnosis
Management	Secure the airway first (controlled intubation in the operating room); IV antibiotics (ceftriaxone or ampicillin-sulbactam); adjunctive corticosteroids
Keywords	"Thumbprint sign," "tripod position," "hot potato voice," "drooling child," "abrupt onset stridor with high fever," "no barking cough"

1. Pathophysiology

Epiglottitis is an acute bacterial cellulitis of the epiglottis and surrounding supraglottic structures, including the aryepiglottic folds, arytenoids, and vallecula. The infection causes rapid-onset inflammatory edema of these structures, which is the central mechanism driving all clinical features.

The epiglottis is a leaf-shaped cartilaginous structure covered by a thin, loosely adherent mucosa. Because the submucosa on the lingual (anterior) surface of the epiglottis is loose areolar tissue, it can swell dramatically within hours once an infection establishes itself. This is fundamentally different from the subglottic region (involved in croup), where the mucosa is tightly bound to the underlying cartilage and swelling progresses more slowly.

As the epiglottis swells, it curls posteriorly and inferiorly, progressively occluding the airway inlet. This explains the stridor (turbulent airflow through a narrowing supraglottic aperture) and the patient's instinctive adoption of the tripod position, which maximizes the anteroposterior diameter of the hypopharynx. The patient leans forward and extends the neck to physically pull the swollen epiglottis away from the posterior pharyngeal wall, maintaining a patent airway.

Dysphagia and drooling result directly from the intense pain and mechanical obstruction at the level of the epiglottis. The patient cannot swallow secretions because the act of swallowing requires the epiglottis to fold down over the laryngeal inlet, and this movement is excruciatingly painful and mechanically impaired. Pooling of secretions in the hypopharynx produces the characteristic drooling.

The muffled or "hot potato" voice arises because the supraglottic swelling alters the resonating chamber above the vocal cords. Importantly, the vocal cords themselves are typically uninvolved early in the disease, so the voice is muffled rather than hoarse. This contrasts with croup, where subglottic edema directly affects the cords and produces hoarseness.

The absence of a barking cough is a critical distinguishing feature. In croup, inflammation at the subglottic level irritates the vocal cords and triggers a characteristic seal-bark cough. In epiglottitis, the pathology sits above the cords, so there is no direct stimulation of the cough reflex at the glottic level. Additionally, patients with epiglottitis instinctively suppress coughing because any movement of the inflamed epiglottis worsens pain and risks precipitating complete obstruction.

In the pre-vaccination era, Hib was responsible for the vast majority of pediatric cases. Since the introduction of the conjugate Hib vaccine, the epidemiology has shifted substantially. Pediatric epiglottitis has become rare, and the condition is now more frequently encountered in adults, where the microbiology is more diverse (including group A Streptococcus, S. aureus, and non-typeable H. influenzae). Non-infectious causes such as thermal injury, caustic ingestion, and foreign body irritation can also produce a similar clinical picture.

2. Classification and Clinical Manifestation

Epiglottitis does not have a formal staging system, but clinical manifestation can be organized by severity and by the differences between pediatric and adult presentations, which is highly testable.

Severity Progression

Stage	Clinical Features	Airway Status
Early (Mild)	Sore throat disproportionate to oropharyngeal findings, odynophagia, low-grade fever, subtle voice change	Patent; no stridor at rest
Moderate	High fever, muffled voice, drooling, preference for sitting upright, mild inspiratory stridor at rest	Partially compromised; stridor indicates >50% narrowing
Severe (Impending Obstruction)	Tripod positioning, marked stridor, air hunger, anxiety, cyanosis, inability to phonate	Critically compromised; total obstruction imminent

Pediatric vs. Adult Presentation

Feature	Pediatric (Classic)	Adult
Onset	Fulminant; hours	Often more indolent; may evolve over 1 to 2 days
Predominant Symptom	Drooling and refusal to swallow	Severe sore throat and odynophagia
Fever	Very high (>39.5 C), toxic-appearing	Variable; may be moderate
Airway Compromise	Rapid and more dangerous (smaller airway diameter)	Slower progression; still potentially fatal
Cough	Absent	Typically absent or minimal
Position	Tripod / sniffing position	Prefers upright position
Organism	Hib (in unvaccinated)	Polymicrobial or non-Hib organisms

A key clinical pearl: in adults, epiglottitis is frequently underdiagnosed on initial presentation because the chief complaint of "worst sore throat of my life" with a relatively normal-appearing oropharynx gets attributed to pharyngitis. The discrepancy between the severity of throat pain and the paucity of visible pharyngeal findings should raise suspicion.

3. Diagnostic Workup

Test	Role	Key Finding
Lateral Neck Radiograph	Best initial test (when patient is stable)	Thumbprint sign: enlarged, rounded epiglottis replacing the normal thin, pencil-like shadow
Direct Laryngoscopy / Fiberoptic Nasopharyngoscopy	Most accurate (confirmatory) test	Cherry-red, edematous epiglottis with swollen aryepiglottic folds; performed only in a controlled environment
Blood Cultures	Identify causative organism	Positive in approximately 25% of cases
CBC	Supportive	Leukocytosis with left shift
Epiglottic Surface Culture	Organism identification	Obtained at time of intubation if possible

The lateral neck X-ray is the best initial test when the patient is hemodynamically stable and does not show signs of imminent airway compromise. It is obtained in the upright position (never supine, as this can worsen obstruction). The hallmark finding is the thumbprint sign, which represents the swollen epiglottis silhouetted against the air column of the hypopharynx. The normal epiglottis appears as a thin, well-defined shadow (often described as a "pinky finger" or "pencil" shape), and this loss of normal contour is highly suggestive.

Secondarily, the lateral neck film may also show thickened aryepiglottic folds, ballooning of the hypopharynx, and loss of the vallecular air space. The subglottic region will appear normal on the same film, which helps exclude croup (where you would instead see the steeple sign from subglottic narrowing).

Direct visualization is the gold standard and most accurate test. In children, this is ideally performed in the operating room by an anesthesiologist or otolaryngologist prepared for immediate intubation or surgical airway. In cooperative adults with mild to moderate symptoms, fiberoptic nasopharyngoscopy can be performed at the bedside by an experienced clinician. The classic finding is a swollen, cherry-red epiglottis.

Critical rule for exam vignettes: In a child with suspected epiglottitis who appears toxic and has stridor, do not attempt to examine the throat, do not lay the child supine, and do not attempt to obtain a throat swab or tongue depressor exam. These maneuvers can trigger laryngospasm and complete airway obstruction. The next best step is to take the child directly to the operating room for controlled airway management. Diagnostic imaging is secondary to securing the airway if the clinical picture is convincing.

Blood cultures should be drawn before initiating antibiotics, though they are positive in only about one-quarter of cases. A CBC will typically show leukocytosis but is nondiagnostic. Surface cultures from the epiglottis, when obtainable during intubation, provide the highest microbiologic yield.

4. Management and Treatment

Phase	Intervention	Details
Immediate	Airway management	Controlled endotracheal intubation in OR (preferred); surgical airway (tracheostomy/cricothyrotomy) if intubation fails
Pharmacologic (First-line)	Ceftriaxone	Pediatric: 50 to 100 mg/kg/day IV divided q12 to 24h (max 4 g/day). Adult: 1 to 2 g IV every 12 to 24 hours
Pharmacologic (Alternative)	Ampicillin-sulbactam	Pediatric: 200 to 300 mg/kg/day of ampicillin component IV divided q6h. Adult: 3 g IV every 6 hours
Adjunctive	Dexamethasone	0.5 to 0.6 mg/kg IV (max 10 mg); role is to reduce supraglottic edema and facilitate earlier extubation
Adjunctive	Nebulized epinephrine	May provide temporary relief but is not definitive; used as a bridge
Duration	IV antibiotics then oral step-down	7 to 10 days total; transition to oral (amoxicillin-clavulanate) when afebrile, able to swallow, and extubated
Chemoprophylaxis	Rifampin for household contacts	20 mg/kg/day (max 600 mg) once daily for 4 days; indicated when Hib is confirmed and there is a household contact under 4 years who is unvaccinated or incompletely vaccinated

Step 1: Airway takes absolute priority. This is the single most important concept tested on exam questions about epiglottitis. If a vignette describes a toxic child with drooling, stridor, and high fever, the next best step is not to obtain an X-ray, not to start antibiotics, and not to examine the oropharynx. The correct answer is to prepare for controlled airway management in the operating room. The child should be kept calm (often sitting in a parent's lap), supplemental humidified oxygen should be provided without agitating the patient, and an anesthesiologist and surgical team should be mobilized.

Step 2: Endotracheal intubation is the preferred method of airway control and is performed in the operating room under inhalational anesthesia (typically sevoflurane). The tube used is generally 0.5 to 1.0 mm smaller than predicted for the child's age, given the supraglottic swelling. If intubation fails, an emergent surgical airway (tracheostomy in children, cricothyrotomy in adults) is the backup.

Step 3: Once the airway is secured, IV antibiotics are initiated. Third-generation cephalosporins (ceftriaxone) are the standard empiric choice because they provide excellent coverage against Hib, Streptococcus species, and most respiratory pathogens. Ampicillin-sulbactam is the preferred alternative and provides additional anaerobic coverage. In patients with a true penicillin and cephalosporin allergy, a combination of a fluoroquinolone plus clindamycin can be used.

Step 4: Adjunctive dexamethasone is commonly administered, though evidence is not definitive. The rationale is to reduce inflammatory edema and potentially shorten the duration of intubation. Most patients are extubated within 24 to 72 hours once the supraglottic swelling subsides (monitored by an air leak test or repeat laryngoscopy).

Step 5: Transition to oral antibiotics occurs when the patient is afebrile, tolerating oral intake, and extubated. Amoxicillin-clavulanate is the most common oral step-down agent. The total antibiotic course is 7 to 10 days.

Step 6: Rifampin chemoprophylaxis is indicated when Hib epiglottitis is confirmed and there is a household contact younger than 4 years who is unvaccinated or incompletely vaccinated. The index patient should also receive rifampin prophylaxis before discharge to eradicate nasopharyngeal carriage, as treatment-dose antibiotics do not reliably clear colonization.

5. Differential Diagnosis and Distractors

Differential	Why It Is Similar	Key Discriminator
Croup (Laryngotracheobronchitis)	Both cause stridor in young children	Croup has a barking (seal-like) cough, hoarseness, and a gradual onset over days preceded by URI symptoms. Fever is typically low-grade. X-ray shows a steeple sign (subglottic narrowing), not a thumbprint sign. No drooling.
Retropharyngeal Abscess	High fever, drooling, neck stiffness, refusal to swallow in a young child	Patient presents with neck hyperextension (not flexion/sniffing), limited neck movement, and a bulging posterior pharyngeal wall on exam. CT neck with contrast shows a rim-enhancing fluid collection in the prevertebral space.
Peritonsillar Abscess (Quinsy)	Severe sore throat, drooling, muffled voice, fever	Trismus (inability to open the mouth) is the hallmark discriminator. Exam shows unilateral tonsillar swelling with uvular deviation to the contralateral side. This is an adolescent/adult diagnosis, not typical in young children.
Bacterial Tracheitis	Toxic child with stridor and high fever who does not respond to croup treatment	Typically follows a viral croup prodrome. The child produces thick purulent secretions and has subglottic irregularity (not supraglottic swelling) on imaging. Often caused by S. aureus.
Foreign Body Aspiration	Acute stridor, respiratory distress	Sudden onset in a previously well child, often with a witnessed choking episode. There is no fever. Chest X-ray or airway film may show a radiopaque object or unilateral hyperinflation (air trapping).
Anaphylaxis	Rapid-onset stridor and airway compromise	Associated with urticaria, hypotension, and exposure to a known allergen. No fever. Responds to intramuscular epinephrine.

6. Traps and High-Yield Pearls

The most common way students lose points on epiglottitis questions is by selecting a diagnostic step before securing the airway. Test writers frequently construct a vignette with a toxic, drooling, febrile child with stridor and then offer answer choices such as "obtain lateral neck X-ray," "perform throat examination," "start IV ceftriaxone," and "take the patient to the operating room for airway management." The correct answer is always the airway. Antibiotics, imaging, and even IV access are secondary. If the clinical presentation is convincing and the child is in distress, you do not delay for confirmatory imaging.

The second common trap is confusing epiglottitis with croup. Both cause stridor. The distinguishing features are the tempo (hours vs. days), the presence or absence of a barking cough (absent in epiglottitis), the appearance of the child (toxic vs. non-toxic), and the radiographic sign (thumbprint vs. steeple). Test writers rely on students conflating these two diagnoses, so look for the combination of abrupt onset, high fever, drooling, and absence of cough to lock in epiglottitis.

A third tested concept is the "do not disturb" principle in pediatric epiglottitis. Any answer choice that involves agitating the child (tongue depressor, throat culture, placing the child supine, inserting an IV before the airway team is ready) is wrong. These maneuvers can convert a partially obstructed airway into a completely obstructed one.

Finally, be aware that the epidemiology question can appear: the Hib vaccine has dramatically reduced pediatric epiglottitis, so a vignette describing classic epiglottitis in a child will almost always mention that the child is unvaccinated or has an incomplete immunization history. In contrast, an adult with epiglottitis will not have this clue and will present with severe odynophagia out of proportion to visible pharyngeal findings. Recognizing the adult variant requires a higher index of suspicion and awareness that epiglottitis is no longer just a pediatric disease.

The core competency being tested is the ability to recognize a life-threatening upper airway emergency, prioritize airway management over diagnostic workup, and distinguish supraglottic pathology from subglottic pathology based on clinical and radiographic features.

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