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Retropharyngeal Abscess

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Retropharyngeal Abscess, Parapharyngeal Abscess, Parapharyngeal Space Infection

  • See Also
  1. Pharyngitis
  2. Pharyngitis Causes
  3. Peritonsillar Abscess
  4. Ludwig's Angina
  5. Lemierre Syndrome
  • 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 posterior pharyngeal wall and prevertebral fascia of Cervical Spine
    2. Retropharyngeal space extends from base of skull to posterior mediastinum
    3. Retropharyngeal space contains Lymph Node chains draining the upper respiratory tract
      1. Upper Respiratory Infections may spread to retropharyngeal Lymph Nodes and seed the associated space
      2. However Retropharyngeal Lymph Nodes often involute by age 4 to 5 years
    4. Retropharyngeal Abscess has 2 major causes
      1. Penetrating oropharyngeal Trauma (25%)
      2. URI spread to retropharyngeal Lymph Nodes (50%)
  • 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. Penetrating oropharyngeal Trauma
    2. Airway Foreign Body
    3. Pharyngeal procedures
    4. Adjacent infections (e.g. Dental Infections)
  • Pathophysiology
  1. Retropharyngeal Lymph Nodes not atrophied in children allow for seeding of Bacteria into the retropharyngeal space
  2. Mixed aerobic and anaerobic flora infection transmitted from the more anterior parapharyngeal space (see causes below)
  3. Accumulation of pus in retropharyngeal space (results in abscess formation)
  • Risk Factors
  1. Children under age 6 years
  2. Upper Respiratory Infection (URI)
    1. URI results in retropharyngeal Lymphadenitis and precedes 50% of Retropharyngeal Abscesses
  3. Upper airway Trauma (see causes below)
  4. Immunocompromised Condition
    1. HIV Infection
    2. Diabetes Mellitus
  • 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)
  • Causes
  • Organisms
  1. Often Polymicrobial
  2. Common Causes
    1. Group A Streptococcus (Streptococcus Pyogenes)
    2. Viridans Streptococcus
    3. Anaerobic Bacteria (e.g. Fusobacterium)
  3. Less common causes
    1. Staphylococcus Aureus including MRSA (less common)
    2. Haemophilus Influenzae (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)
  • Symptoms
  1. Fever
  2. Neck Pain (out of proportion to findings)
    1. Worse with neck extension posteriorly, and patient prefers to hold neck in flexion
    2. Contrast with Epiglottitis and Meningitis in which patient prefers to hold their neck in extension
  3. Dysphagia and odynophagia
  4. Drooling
  5. Decreased oral intake
  6. Palliative measures
    1. Patients prefer supine position (less encroachment on airway)
  • Signs
  1. Children may appear well despite significant abscess
  2. May be difficult to appreciate pharyngeal fullness
    1. Posterior pharyngeal wall may bulge (but variably present)
  3. Airway compromise may be present with larger abscesses (3-5% of cases, slower progression than Epiglottitis)
    1. Respiratory distress (e.g. Tachypnea)
    2. Inspiratory Stridor
    3. Muffled voice or hot potato voice
  4. Neck Pain, stiffness or Torticollis (esp. difficult neck extension)
  5. Trismus
  • Labs
  1. Complete Blood Count
    1. Leukocytosis >12.0 (x10^9/L) present in 91% of cases
  2. Blood Culture
  • Imaging
  1. Lateral neck XRay
    1. Perform with neck in neutral position, during inspiration
    2. Bulging of posterior pharyngeal wall
    3. Prevertebral soft tissue width increased (beyond the width of the associated Vertebral body)
      1. C2 level prevertebral space >7 mm (adults and children)
      2. C6 level prevertebral space >14 mm (children) or >22 mm (adults)
    4. False Positive prevertebral widening (pseudothickening) may occur with less ideal films
      1. Good image requires patient cooperation
      2. Should be exactly lateral position with neck held in neutral position (normal extension)
      3. Should be an inspiratory film
      4. Crying may also cause a False Positive widening
  2. CT Soft Tissue Neck with Contrast
    1. CT is gold standard (but CT-associated Radiation Exposure is a concern, esp. in 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)
  3. MRI Neck
    1. MRI Neck may also be considered for no radiation
    2. Not typically practical (esp. in Unstable Patient)
      1. Long scan times
      2. Lack of MRI availability
      3. Requires sedation in younger children
  4. Neck Ultrasound
    1. Requires skilled Ultrasound technique
    2. Patient must tolerate endocavitary Ultrasound probe in the posterior pharynx to allow for imaging
  • Differential Diagnosis
  1. See Pharyngitis Causes
  2. See Stridor
  3. See Pediatric Obstructed Airway Causes
  4. Meningitis (Nuchal Rigidity)
  5. Epiglottitis (airway compromise)
  6. Peritonsillar Abscess
  • Management
  1. Hospitalize
  2. Airway observation
    1. See ABC Management
    2. 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
      1. Larger abscess >=3 cm
      2. Airway compromise
      3. Failure to improve after 48 to 72 hours on IV Antibiotics
      4. Immunocompromised state
      5. Significant Leukocytosis
    2. Conservative therapy with IV Antibiotics alone sufficient in 35-58% of cases
      1. Small abscess (<3 cm)
      2. No airway compromise
  4. Intravenous Antibiotics
    1. Duration (total treatment course): 2-3 weeks
    2. Oropharyngeal Bacterial coverage
      1. Pyogenic Streptococcus and Staphylococcus
      2. Anaerobic Bacteria
    3. Initial empiric Antibiotics
      1. Ampicillin-Sulbactam (Unasyn) 3 g IV every 6 hours
      2. Clindamycin 600-900 mg IV every 8 hours OR Metronidazole 1 g IV every 12 hours AND
        1. Levofloxacin 750 mg IV every 24 hours OR
        2. Ceftriaxone 2 g IV every 24 hours AND
    4. Methicillin Resistant Staphyococcus aureus (MRSA) detected or suspected
      1. Add Vancomycin
    5. Pseudononas coverage
      1. Piperacillin-Tazobactam (Zosyn) 3.375 g IV every 6 hours OR
      2. Cefepime and Metronidazole
  5. Other medications
    1. Corticosteroids (e.g. Dexamethasone)
      1. Reduces risk of requiring Surgical Drainage
      2. Goenka (2021) Pediatrics 148(5): e2020037010 [PubMed]
  • 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)
  • Resources
  1. Stat Pearls
    1. https://www.ncbi.nlm.nih.gov/books/NBK441873/
  • References
  1. Aldden and Rosenbaum (2017) Emergency Medicine Board Review, Wolters Kluwer
  2. Ayoub (2026) Crit Dec Emerg Med 40(10): 4-12
  3. Dahan, Campbell and Melville (2020) Crit Dec Emerg Med 34(11): 3-10
  4. Guess and Pittman (2022) Crit Dec Emerg Med 36(7): 12-4
  5. Okuda and Nelson (2015) Emergency Medicine Board Review, Cambridge University Press, New York, p. 103-7
  6. (2020) Sanford Guide, accessed 1/19/2020