Quick Overview
- Definition: A purulent collection in the retropharyngeal space, extending from the skull base to T3; most common in children <6 years due to retropharyngeal lymph nodes, but can also occur in adults.
- Risk? Risk of airway obstruction, extension into the danger space down to the mediastinum (descending mediastinitis), jugular vein thrombosis, and vascular/neurologic injury.
- Microbiology: Mixed oral flora, both aerobic and anaerobic: β-hemolytic streptococci, S. aureus, S. pneumoniae, H. influenzae, Fusobacteria, etc. (anaerobic coverage always important).
Rapid Assessment in the Emergency Room (Triage → ABC)
- A – Airway first:
- Warning signs: stridor, muffled/altered voice, drooling, tachypnea, “sniffing” posture, rapid deterioration.
- Do not forcefully inspect the oropharynx or depress the tongue aggressively if airway compromise is suspected.
- Prepare for intubation in the OR with anesthesia + ENT, and have a backup plan (tracheostomy/cricothyrotomy) if failed.
- B – Breathing & C – Circulation: Monitor SpO₂, give IV fluids if dehydrated, provide analgesics and antipyretics.
- Labs: CBC, CRP/ESR, blood cultures before antibiotics when feasible.
Imaging
1) CECT (Contrast-Enhanced CT) — the practical standard in the ED
- When? Strong clinical suspicion, suspected deep/mediastinal spread, or when surgical drainage is being considered.
- Provides anatomical extension/volume mapping. However: not perfect in distinguishing abscess vs. phlegmon (positive predictive value limited).
- How to read it? Look for a rim-enhancing cavity, intralesional gas, airway displacement/compression, and extension into the danger space. A clear cavity strongly suggests need for drainage.
2) POCUS / Ultrasound — selective adjunct
- When useful? In children (to reduce radiation), or for guiding aspiration/drainage; not a substitute for CECT when deeper/mediastinal extension or complications are suspected.
- Quick technical note (transcervical): High-frequency linear probe, patient semi-sitting, sagittal/transverse scan along anterior SCM border. Look for a hypoechoic collection posterior to the pharyngeal wall with rim enhancement/membrane; attempt gentle compression — abscess is non-compressible vs. phlegmon.
3) MRI (when needed)
- When? If higher tissue resolution is desired (abscess vs. phlegmon, fascial plane extension, suspicion of vertebral/cord involvement, vascular complications), or to reduce radiation in children at centers with rapid emergency protocols (5-min: T2 Dixon + DWI).
- Recent studies show excellent accuracy for short MRI protocols without contrast; advantageous over CECT for content and extent differentiation, but less available in emergencies.
Antimicrobial Protocol
Start IV antibiotics after drawing blood cultures whenever possible — but do not delay if airway stabilization is urgent.
Children
- First-line:
- Cefotaxime IV: 30–50 mg/kg q8h (max 6 g/day).
- Metronidazole IV: 7.5–13 mg/kg q8h (max 500 mg TID, daily max 4 g).
- Alternative to metronidazole: Clindamycin IV: 7 mg/kg q8h (max 1.8 g/day).
- Second-line:
- Piperacillin/Tazobactam IV: <12 yrs: 80 mg/kg q6h (up to 4 × 4 g).
Adults
- First-line:
- Cefotaxime IV: 2 g q8h
- Metronidazole IV: 500 mg q8h
- Alternative to metronidazole: Clindamycin IV: 600 mg q8h
- Second-line:
- Piperacillin/Tazobactam IV: 4 g q6–8h
Penicillin allergy: Use Cefotaxime + (Metronidazole or Clindamycin) as above depending on clinical scenario.
Additional option: In areas with high MRSA prevalence or severe odontogenic source, consider adding temporary MRSA coverage (e.g., Vancomycin) per Infectious Diseases and hospital microbiology guidance.
Surgical Drainage — When?
Clinical/radiological indicators for early drainage:
- No improvement within 24–48 h of conservative therapy.
- Airway compromise or septic toxicity.
- CECT: clear cavity + rim enhancement/gas, or large diameter (~2.4–2.5 cm in pediatric studies).
Practical tip: In children, even if below the “size threshold”, drainage is favored when a true cavity exists and clinical improvement is inadequate.
A) Transoral drainage (limited, bulging pharyngeal abscess)
- OR setup + suction + hemostatic tools + culture specimen.
- Head tilt, dental protection, tongue retraction, visualize retropharyngeal bulge.
- 18–21G needle aspiration first to confirm pus.
- Small vertical incision at the most prominent point, as midline as possible to avoid carotid sheath.
- Gentle widening, suction, irrigation with saline, avoid deep dissection (stay midline to avoid ICA).
B) External cervical approach (large/lateral/mediastinal extension)
- Incision parallel to anterior SCM border at abscess level.
- Careful dissection to retropharyngeal space protecting carotid sheath.
- Open abscess cavity, suction, copious irrigation, insert drain (closed suction).
- Document extent and re-evaluate with imaging if needed.
Tips & Tricks
- Do not lay the patient flat if airway compromised; keep semi-sitting until intubation.
- POCUS useful to identify best aspiration site and avoid vessels near skin.
- On CECT: Rim enhancement + gas = higher chance of successful drainage; firm phlegmon usually yields no pus.
- When to image chest? Any chest pain/dyspnea/high CRP with inferior neck pain → order CECT neck + chest early to rule out mediastinitis and consult thoracic surgery.
- Emergency MRI (5-min) great option when available to reduce radiation and differentiate abscess vs. phlegmon — but never delay airway/therapy for MRI.
Pitfalls
- Starting antibiotics without blood cultures when feasible → limits de-escalation later.
- Aggressive oral exam in a child with threatened airway → may precipitate obstruction.
- Forgetting possible odontogenic source in adults — seek dental consult if suspected.
Follow-up & Discharge
- Clinical/lab improvement within 24–48 h, oral intake tolerated, airway stable, follow-up plan in place.
- Selective imaging re-assessment (not routine) if patient fails to improve or if extension/complications suspected