Acute Epiglottitis: Life-Threatening Airway Emergency, CT Diagnosis, Thumb Sign Radiology, and Evidence-Based Treatment

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Abstract

Acute Epiglottitis is a rapidly progressive, potentially fatal upper airway condition characterized by inflammation and edema of the epiglottis and surrounding supraglottic structures. Despite the widespread implementation of the Haemophilus influenzae type b (Hib) vaccine, epiglottitis remains clinically significant—particularly in adults—requiring prompt recognition and airway management. This column presents a radiology-driven case analysis, integrates CT imaging interpretation, and delivers a comprehensive expert-level review including pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, treatment strategies, and prognosis. 

Clinical Case Summary

A 60-year-old male presented with:

  • Severe sore throat (2 days)
  • Hoarseness
  • Fever

Physical findings:

  • No stridor, drooling, or respiratory distress
  • Unremarkable oropharyngeal exam

Radiologic findings:

  • Lateral neck X-ray: “Thumb sign.”
  • Contrast-enhanced CT: Enlarged, edematous epiglottis with airway narrowing

Management:

  • IV antibiotics
  • ICU observation
  • Flexible laryngoscopy confirmed inflammation and abscess

Outcome:

  • Improved with medical management (no drainage required)

Figure Interpretation and Radiologic Analysis

Figure 1. Lateral Neck Radiograph (C-Spine Lateral)

Enlarged, edematous epiglottis forming the classic “thumb sign,” indicating acute supraglottic inflammation consistent with epiglottitis.

Interpretation:
The thumb sign represents a swollen epiglottis projecting into the airway, a hallmark radiographic feature of epiglottitis.

Figure 2. Contrast-Enhanced CT (Sagittal View)

Diffuse thickening and edema of the epiglottis with supraglottic airway narrowing. Findings are consistent with acute epiglottitis and possible early abscess formation.

Interpretation:
CT imaging demonstrates:

  • Epiglottic enlargement
  • Soft tissue edema
  • Airway compromise

CT is particularly useful in adult or atypical presentations.

1. Pathophysiology of Epiglottitis

Epiglottitis involves acute inflammation of the epiglottis and adjacent supraglottic tissues, leading to rapid edema and airway obstruction.

Key mechanisms:

  • Bacterial invasion → inflammatory cascade
  • Increased vascular permeability → tissue edema
  • Airway narrowing → respiratory compromise

Most common pathogen:

  • Haemophilus influenzae type b (historically dominant)

Other causes:

  • Streptococcus species
  • Viral superinfection
  • Thermal or chemical injury

Critical insight:
Even minimal swelling can significantly reduce airway diameter, making this a true airway emergency.

2. Epidemiology

  • Incidence: ~1 per 100,000 annually
  • Shift from pediatric → adult predominance after Hib vaccination
  • Adult cases now represent the majority

Risk factors:

  • Immunocompromised state
  • Diabetes mellitus
  • Smoking

3. Clinical Presentation

Classic symptoms:

  • Severe sore throat (out of proportion to exam)
  • Dysphagia / odynophagia
  • Fever
  • Muffled voice (“hot potato voice”)

Advanced signs:

  • Stridor
  • Drooling
  • Respiratory distress

However, adults often present subtly, as in this case.

4. Imaging Features

X-ray Findings

  • Thumb sign → enlarged epiglottis
  • Loss of vallecular air space

CT Findings

  • Epiglottic thickening
  • Supraglottic narrowing
  • Possible abscess

Key Radiologic Insight

Imaging should never delay airway management, especially in unstable patients.

5. Differential Diagnosis

ConditionKey Distinguishing Features
Peritonsillar abscess   Tonsillar asymmetry
Retropharyngeal abscess   Prevertebral soft tissue swelling
Laryngitis   Diffuse inflammation, milder
Foreign body   Sudden onset
Angioedema   Non-infectious swelling

6. Diagnosis

Gold standard:

  • Direct visualization via laryngoscopy

Supportive tools:

  • X-ray (thumb sign)
  • CT scan (complex cases)

Important:
Avoid aggressive throat examination in unstable patients.

7. Treatment (Emergency Airway Management)

Immediate Priorities

  1. Airway protection
  2. ICU monitoring

Medical Treatment

  • IV antibiotics (e.g., ceftriaxone, cefuroxime)
  • Corticosteroids (reduce edema)
  • Oxygen therapy

Advanced Interventions

  • Endotracheal intubation
  • Tracheostomy (severe cases)

Adult patients:

  • <10% require intubation

8. Prognosis

  • Excellent with early treatment
  • Mortality is significantly reduced with modern care
  • Delayed diagnosis → risk of sudden airway obstruction

9. High-Yield Clinical Pearls

  • Severe sore throat + normal exam = red flag
  • Thumb sign = classic but not always present
  • Airway first, imaging second
  • Adult epiglottitis is increasing

Quiz 

Question 1. What is the most characteristic radiographic sign of epiglottitis?

A. Steeple sign
B. Thumb sign
C. Double bubble sign
D. Ground-glass opacity
E. Air-fluid level

Answer: B. Explanation: Enlarged epiglottis produces the thumb-like projection.

Question 2. What is the most critical first step in management?

A. CT scan
B. Antibiotics
C. Airway stabilization
D. Blood culture
E. Steroids

Answer: C. Explanation: Airway compromise is the leading cause of mortality.

Question 3. Which organism is historically most associated?

A. Streptococcus pneumoniae
B. Staphylococcus aureus
C. Haemophilus influenzae type b
D. Mycoplasma pneumoniae
E. Influenza virus

Answer: C. Explanation: Hib was the dominant pathogen before vaccination.

Recommended Reading

  1. Grover C., “Thumb Sign of Epiglottitis,” N Engl J Med, 2011. DOI: https://doi.org/10.1056/NEJMicm1009990
  2. Sutton A.E., et al., “Epiglottitis,” StatPearls, 2024.
  3. Chew F.Y., et al., “Acute Epiglottitis and the Thumb Sign,” QJM, 2024. DOI: https://doi.org/10.1093/qjmed/hcae071
  4. Yu C.W., et al., “Impact of Thumb Sign,” Am J Emerg Med, 2026. DOI: https://doi.org/10.1016/j.ajem.2025.11.011
  5. Takata M., et al., “Thumb Sign Case Report,” BMJ Case Rep, 2016. DOI: https://doi.org/10.1136/bcr-2016-214742
  6. Lee J., et al., “Double Thumb Sign,” Radiol Case Rep, 2021. DOI: https://doi.org/10.1016/j.radcr.2021.04.007
  7. Radiopaedia, “Thumb Sign,” DOI: https://doi.org/10.53347/rID-22909

Final Insight

Acute epiglottitis remains one of the most time-sensitive airway emergencies in modern medicine. This case highlights how subtle symptoms can conceal life-threatening pathology—making radiologic recognition and clinical suspicion essential for survival.



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