II. Definitions

  1. Parapharyngeal Abscess
    1. Purulent collection within pharygeal spaces (lateral pharynx, retropharynx, pretracheal spaces)
    2. Sources include sinuses and middle ear, teeth and Tonsils, as well as Salivary Glands (esp. Parotid Gland)
    3. Oral foreign bodies (e.g. fish bones) may also serve as source
    4. May spread to involve submandibular space (Ludwig's Angina)
  2. Retropharyngeal Abscess
    1. Purulent collection between pharynx and Cervical Spine
    2. Typically occurs from Trauma or URI spread to retropharyngeal Lymph Nodes

III. Epidemiology

  1. Most commonly a disease of infants and young children (age <4-6 years old)
    1. Young children have prominent retropharyngeal Lymph Nodes that atrophy after age 5 years
  2. However, can affect older children and adults
    1. Trauma
    2. Airway Foreign Body
    3. Pharyngeal procedures
    4. Adjacent infections

IV. Pathophysiology

  1. Retropharyngeal Lymph Nodes not atrophied in children
  2. Mixed aerobic and anaerobic flora infection transmitted from the more anterior parapharyngeal space
  3. Accumulation of pus in retropharyngeal space

V. Risk Factors

  1. Children under age 6 years
  2. Upper airway Trauma (see causes below)
  3. Immunocompromised Condition
    1. HIV Infection
    2. Diabetes Mellitus

VI. Causes: Mechanism

  1. Upper Respiratory Infection (more common cause in children)
    1. Sources: Dental Infection, Tonsillitis, parotid Sialadenitis, middle ear infections, Acute Sinusitis
    2. Spreads posteriorly to retropharyngeal Lymph Nodes
  2. Trauma (adults and children)
    1. Vertebral Fracture
    2. Fish bone ingestion
    3. Upper airway instrumentation (Endotracheal Intubation, Nasogastric Tube placement)

VII. Causes: Organisms

  1. Often Polymicrobial
  2. Common Causes
    1. Group A Streptococcus
    2. Viridans Streptococcus
    3. Anaerobic Bacteria (e.g. Fusobacterium)
  3. Less common causes
    1. Staphylococcus aureus including MRSA (less common)
    2. HaemophilusInfluenzae (less common after use of Hib Vaccine)
    3. Tuberculosis (esp. in HIV Infection)
    4. Pseudomonas aeruginosa in high risk groups (e.g. Diabetes Mellitus, IV Drug Abuse, Neutropenia)

VIII. Symptoms

  1. Neck Pain (out of proportion to findings)
    1. Worse with neck extension posteriorly
    2. Contrast with Meningitis which is worse with neck flexion anteriorly
  2. Dysphagia
  3. Odynophagia
  4. Drooling
  5. Fever
  6. Palliative measures
    1. Patients prefer supine position (less encroachment on airway)

IX. Signs

  1. May be difficult to appreciate pharyngeal fullness
  2. Airway compromise may be present
    1. Respiratory distress (e.g. Tachypnea)
    2. Inspiratory Stridor
    3. Muffled voice or hot potato voice
  3. Neck Pain, stiffness or Torticollis
  4. Trismus

XI. Imaging

  1. Lateral neck XRay
    1. Bulging of posterior pharyngeal wall
    2. Prevertebral soft tissue width increased
      1. C2 level prevertebral space >7 mm (adults and children)
      2. C6 level prevertebral space >14 mm (children) or >22 mm (adults)
    3. False Positive prevertebral widening may occur with less ideal films
      1. Good image requires patient cooperation
      2. Should be exactly lateral position
      3. Should be an inspiratory film
      4. Crying may also cause a False Positive widening
  2. CT Soft Tissue Neck with Contrast or MRI Neck
    1. CT is gold standard (but CT-associated Radiation Exposure, esp. children)
    2. Patient must be stable to be in Radiology Department and to lie flat
    3. CT may demonstrate abscess extent (esp. when performed with contrast)
    4. MRI Neck may also be considered for no radiation (but not typically practical, esp. in Unstable Patient)

XII. Management

  1. See ABC Management
  2. Airway observation
    1. Endotracheal Intubation required in up to one third of cases
  3. Early, emergent ENT Consultation for surgical drainage
    1. Incision and Drainage in operating room
  4. Intravenous Antibiotics
    1. Duration (total treatment course): 2-3 weeks
    2. Initial empiric antibiotics
      1. Clindamycin 600-900 mg IV every 8 hours and Levofloxacin 750 mg IV every 24 hours OR
      2. Ceftriaxone 2 g IV every 24 hours AND Metronidazole 1 g IV every 12 hours OR
      3. Ampicillin-Sulbactam (Unasyn) 3 g IV every 6 hours
    3. Staphyococcus aureus detected
      1. Add Vancomycin
    4. Pseudononas coverage
      1. Piperacillin-Tazobactam (Zosyn) 3.375 g IV every 6 hours OR
      2. Cefepime and Metronidazole
  5. Disposition
    1. Hospitalize

XIII. Complications

  1. Airway obstruction (most common fatal complication)
  2. Ludwig's Angina
  3. Atlantoaxial separation (transverse ligament erosion)
  4. Carotid Artery erosion
  5. Jugular Vein thrombosis
    1. Secondary risk of septic Thrombophlebitis (and Lemierre Syndrome)
  6. Descending Necrotizing Mediastinitis
    1. Extension of infection from retropharyngeal space posteriorly into the "danger space" (alar space)
    2. Mortality approaches 40%
  7. Meningoencephalitis
  8. Esophageal Perforation
  9. Horner Syndrome
  10. Cranial Nerve palsy (CN 9, CN 10, CN 11, CN 12)

XV. References

  1. Aldden and Rosenbaum (2017) Emergency Medicine Board Review, Wolters Kluwer
  2. Dahan, Campbell and Melville (2020) Crit Dec Emerg Med 34(11): 3-10
  3. Guess and Pittman (2022) Crit Dec Emerg Med 36(7): 12-4
  4. Okuda and Nelson (2015) Emergency Medicine Board Review, Cambridge University Press, New York, p. 103-7
  5. (2020) Sanford Guide, accessed 1/19/2020

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