Retropharyngeal Abscess
also see Peritonsillar abscess

Who?

• adults rare, because the retropharyngeal nodes regress in childhood
• Main age group: 6-12 months (50% of cases); 96% <6yo; in general: ONLY children < 4 yo.
   

History

• prodrome: recent/current history of acute naso/pharyngitis - causes suppuration of retropharyngeal lymph nodes
• refusal to feed, severe throat pain, drooling, stridor, raspy voice/cry, barky cough
• trauma: foreign body aspiration, dental procedures, intubation attempts

Presentation

• prodrome: pharyngitis
• high fever
• dysphagia, odynophagia, drooling
• muffled voice, dysphonia - like a duck (cri du canard)
• appears ill, supine, next extended, (tripod)
• respiratory difficulty, stridor
• ET intubation is difficult, hazardous

PE:

• posterior pharynx edema, erythema
• tender cervical LAD
• tender cervical musculature
• high fever
• trismus (aka lockjaw; persistent contraction of masseter muscles due to failure of central inhibition; often the initial manifestation of generalized tetanus)
• meningismus due to irritation of paravertebral ligaments
• palpation of a fluctuant mass is unreliable - can risk rupture
• tracheal rock sign - tenderness on moving trachea side to side
• when swallow, pain in shoulder, back of neck
• erythematous mass with forward displacement of uvula and ipsilateral tonsil

Etiology

• usually a complication of bacterial pharyngitis
• also implicated: nasopharyngitis, OM, parotitis, tonsillitis, peritonsillar abscess, dental infxn/procedure, endoscopy, ludwig angina (Ludwig's Angina link)
• penetrating injury of posterior pharynx (stick or toy in mouth, toothbrush, lollipop -> fall)
• extension from vertebral body osteomyelitis

Bugs

• polymicrobial (aerobic/anaerobic).
• #1 GABHS
• #2 oral anaerobes (traumatic, Bacteroides,Peptostreptococcus,Fusobacterium)
• #3 S. aureus.

Anatomy

•  <3-4 yo - prominent LN that may become infected
• Lymphoid tissue located within the space drains the nasopharynx, adenoids and posterior paranasal sinuses. This lymphoid tissue begins to atrophy about the 3rd or 4th year of life.
• nodes atrophy, age 4-6
• potential space between prevertebral fascia and posterior pharyngeal wall
• superior border = base of skull
• inferior border = tracheal bifurcation
• may erode to prevertebral space and diaphragm
• track to: mediastinum, back of neck, axilla
• erosion into esophagus and auditory canal - aspiration

Dx:

• clinical and X-rays
• lateral neck xray, in mild extension: will see widening of retropharyngeal soft tissues and forward displacement of esophagus/trachea. (Soft tissue width > 1/2 of adj vertebral body)
• soft tissue swelling: if diffuse, then cellulitis. If focal, then abscess.
• CXR to see if mediastinal extension
• these studies, however, may not be sensitive enough... CT with contrast or MRI will help diagnose cellulitis vs abscess. An ultrasound can also help this differential

DDx

• If high fever, barky cough: croup
• limited neck motion may be mistaken for meningismus
• lymphadenitis
• Tb of C-spine
• retropharyngeal tumor, foreign body hematoma, aneurysm
   

Tx:

• airway stabilization
• hydration
• if prefluctuant: use a semisynthetic penicillin to cover for penicillinase producing staph
  • also: clinda or unasyn
  • use narcotics with care (airway obstruction)
  • if fluctuant: I&D under general anesthesia and start abx
• consult ENT.

Retropharyngeal vs Peritonsillar

• R: < 6 yo, P: Teens
• R: fever, sore throat, neck stiffness
• P: fever, sore throat, trismus
• R: purulence of retropharyngeal LN
• P: purulence in tonsillar fossa
• R: may need imaging
• P: PE diagnostic

CHLA Board Review 2005, other sources