II. Definitions
- Parapharyngeal Abscess
- Purulent collection within pharygeal spaces (lateral pharynx, retropharynx, pretracheal spaces)
- Sources include sinuses and middle ear, teeth and Tonsils, as well as Salivary Glands (esp. Parotid Gland)
- Oral foreign bodies (e.g. fish bones) may also serve as source
- May spread to involve submandibular space (Ludwig's Angina)
- Retropharyngeal Abscess
- Purulent collection between posterior pharyngeal wall and prevertebral fascia of Cervical Spine
- Retropharyngeal space extends from base of skull to posterior mediastinum
- Retropharyngeal space contains Lymph Node chains draining the upper respiratory tract
- However Retropharyngeal Lymph Nodes often involute by age 4 to 5 years
- Retropharyngeal Abscess has 2 major causes
- Trauma (25%)
- URI spread to retropharyngeal Lymph Nodes (50%)
III. Epidemiology
- Most commonly a disease of infants and young children (age <4-6 years old)
- Young children have prominent retropharyngeal Lymph Nodes that atrophy after age 5 years
- However, can affect older children and adults
- Trauma
- Airway Foreign Body
- Pharyngeal procedures
- Adjacent infections
IV. Pathophysiology
- Retropharyngeal Lymph Nodes not atrophied in children
- Mixed aerobic and anaerobic flora infection transmitted from the more anterior parapharyngeal space
- Accumulation of pus in retropharyngeal space
V. Risk Factors
- Children under age 6 years
-
Upper Respiratory Infection (URI)
- URI results in retropharyngeal Lymphadenitis and precedes 50% of Retropharyngeal Abscesses
- Upper airway Trauma (see causes below)
- Immunocompromised Condition
VI. Causes: Mechanism
-
Upper Respiratory Infection (more common cause in children)
- Sources: Dental Infection, Tonsillitis, parotid Sialadenitis, middle ear infections, Acute Sinusitis
- Spreads posteriorly to retropharyngeal Lymph Nodes
-
Trauma (adults and children)
- Vertebral Fracture
- Fish bone ingestion
- Upper airway instrumentation (Endotracheal Intubation, Nasogastric Tube placement)
VII. Causes: Organisms
- Often Polymicrobial
- Common Causes
- Group A Streptococcus
- Viridans Streptococcus
- Anaerobic Bacteria (e.g. Fusobacterium)
- Less common causes
- Staphylococcus aureus including MRSA (less common)
- HaemophilusInfluenzae (less common after use of Hib Vaccine)
- Tuberculosis (esp. in HIV Infection)
- Pseudomonas aeruginosa in high risk groups (e.g. Diabetes Mellitus, IV Drug Abuse, Neutropenia)
VIII. Symptoms
-
Neck Pain (out of proportion to findings)
- Worse with neck extension posteriorly, and patient prefers to hold neck in flexion
- Contrast with Epiglottitis and Meningitis in which patient prefers to hold their neck in extension
- Dysphagia
- Odynophagia
- Drooling
- Fever
- Palliative measures
- Patients prefer supine position (less encroachment on airway)
IX. Signs
- May be difficult to appreciate pharyngeal fullness
- Airway compromise may be present
- Respiratory distress (e.g. Tachypnea)
- Inspiratory Stridor
- Muffled voice or hot potato voice
- Neck Pain, stiffness or Torticollis
- Trismus
X. Labs
-
Complete Blood Count
- Leukocytosis >12.0 (x10^9/L) present in 91% of cases
- Blood Culture
XI. Imaging
- Lateral neck XRay
- Bulging of posterior pharyngeal wall
- Prevertebral soft tissue width increased
- C2 level prevertebral space >7 mm (adults and children)
- C6 level prevertebral space >14 mm (children) or >22 mm (adults)
- False Positive prevertebral widening may occur with less ideal films
- Good image requires patient cooperation
- Should be exactly lateral position with neck held in normal extension
- Should be an inspiratory film
- Crying may also cause a False Positive widening
- CT Soft Tissue Neck with Contrast or MRI Neck
- CT is gold standard (but CT-associated Radiation Exposure, esp. children)
- Patient must be stable to be in Radiology Department and to lie flat
- CT may demonstrate abscess extent (esp. when performed with contrast)
- MRI Neck may also be considered for no radiation (but not typically practical, esp. in Unstable Patient)
XII. Differential Diagnosis
XIII. Management
- See ABC Management
- Airway observation
- Endotracheal Intubation required in up to one third of cases
- Early, emergent ENT Consultation for surgical drainage
- Incision and Drainage in operating room
- Intravenous Antibiotics
- Duration (total treatment course): 2-3 weeks
- Initial empiric Antibiotics
- Clindamycin 600-900 mg IV every 8 hours and Levofloxacin 750 mg IV every 24 hours OR
- Ceftriaxone 2 g IV every 24 hours AND Metronidazole 1 g IV every 12 hours OR
- Ampicillin-Sulbactam (Unasyn) 3 g IV every 6 hours
- Staphyococcus aureus detected
- Add Vancomycin
- Pseudononas coverage
- Piperacillin-Tazobactam (Zosyn) 3.375 g IV every 6 hours OR
- Cefepime and Metronidazole
- Disposition
- Hospitalize
XIV. Complications
- Airway obstruction (most common fatal complication)
- Ludwig's Angina
- Atlantoaxial separation (transverse ligament erosion)
- Carotid Artery erosion
-
Jugular Vein thrombosis
- Secondary risk of septic Thrombophlebitis (and Lemierre Syndrome)
- Descending Necrotizing Mediastinitis
- Extension of infection from retropharyngeal space posteriorly into the "danger space" (alar space)
- Mortality approaches 40%
- Meningoencephalitis
- Esophageal Perforation
- Horner Syndrome
- Cranial Nerve palsy (CN 9, CN 10, CN 11, CN 12)
XV. Resources
XVI. References
- Aldden and Rosenbaum (2017) Emergency Medicine Board Review, Wolters Kluwer
- Dahan, Campbell and Melville (2020) Crit Dec Emerg Med 34(11): 3-10
- Guess and Pittman (2022) Crit Dec Emerg Med 36(7): 12-4
- Okuda and Nelson (2015) Emergency Medicine Board Review, Cambridge University Press, New York, p. 103-7
- (2020) Sanford Guide, accessed 1/19/2020