Retropharyngeal Abscess, Emergency Medicine

Basics

Description

Deep tissue infection of the retropharyngeal space:
- Potential space bound anteriorly by buccopharyngeal fascia, posteriorly by alar fascia, superiorly by skull base, inferiorly by fusion of fascial layers at T2
- Space fused by raphe at midline with chains of lymph nodes extending down each side
- Alar fascia is poor barrier and allows retropharyngeal infections to spread into "danger " space and posterior mediastinum
Primarily a disease of children, but increasing frequency in adults:
- Peak incidence at 3 " 5 yr when retropharyngeal nodes most prominent
Prognosis is good when promptly diagnosed and aggressively managed with IV antibiotics and/or surgical drainage
Complications due to mass effect, rupture, or spread are the major source of morbidity and include:
- Airway compromise (most common)
- Aspiration pneumonia due to rupture
- Sepsis
- Spontaneous perforation
- Necrotizing fasciitis
- Mediastinitis
- Thrombosis of the internal jugular vein
- Jugular vein suppurative thrombophlebitis (Lemierre syndrome)
- Erosion into carotid artery (primarily adults)
- Atlantoaxial dislocation from erosion of ligaments
- Cranial nerve palsies (typically IX " XII)
- Epidural abscess
- Recurrent abscess formation (1 " 5%)

Etiology

Causes:
- Most often arises from infection of nasopharynx, paranasal sinuses, or middle ear
- Infection then spreads to lymph nodes between posterior pharyngeal wall and alar fascia
- Trauma, foreign bodies, and iatrogenic introduction of infection from instrumentation also common cause, especially in adults
- Diabetes and other immunosuppressed states may predispose to this infection
Bacteriology: Predominately polymicrobial with anaerobes and aerobes
Most common organisms are:
- Streptococcus pyogenes and Streptococcus viridans
- Staphylococcus aureus (including MRSA)
- Respiratory anaerobes (including Prevotella, Fusobacterium, and Veillonella)
Less common organisms are:
- Haemophilus species
- Acid-fast bacilli
- Klebsiella pneumoniae
- Escherichia coli
- Mycobacterium tuberculosis
- Aspergillus and Candida species

Diagnosis

Signs and Symptoms

May differ between adults and children
History

Most common:
- Sore throat
- Neck pain/stiffness
- Odynophagia
- Dysphagia
- Fever
Additional presenting symptoms:
- Stridor, dyspnea
- Muffled voice
- Trismus

Young children may present with only:

Poor oral intake
Lethargy or irritability
Cough

Physical Exam

Adults:
- Posterior pharyngeal edema
- Nuchal rigidity
- Cervical adenopathy
- Fever (67%)
- Drooling
- Stridor
- Dysphonia (cri du canard)
- Tracheal "rock " sign: Tenderness on moving the larynx and trachea side to side
Children and infants:
- Cervical adenopathy
- Fever
- Neck stiffness with extension most frequently limited
- Retropharyngeal bulge
- Trismus
- Torticollis
- Drooling
- Agitation
- Respiratory distress

Essential Workup

Rapid assessment of airway and respiratory status:

Normal exam does not rule out diagnosis
No lab tests make the diagnosis
When suspicious, obtain lateral neck x-ray or CT of neck with IV contrast

Diagnosis Tests & Interpretation

Lab

CBC (WBC >12,000 in 91% of children):
- Nonspecific
Blood cultures (both aerobic and anaerobic)
Throat cultures

Imaging

Portable films appropriate if concern for airway compromise
Lateral neck radiographs:
- Film taken in inspiration with neck slightly extended
- May not get good exposure of soft tissue if cannot adequately extend neck due to pain or difficulty cooperating in young age
- Increased suspicion if:
  - Retropharyngeal space anterior to C2 >7 mm or 2 the diameter of the vertebral body (sensitivity 90%)
  - Space anterior to C6 >14 mm in preschool children or 22 mm in adults
  - Loss of normal cervical lordosis
Chest radiograph:
- Indicated if abscess identified to assess for inferior spread of infection and/or aspiration of ruptured abscess contents
- Mediastinal widening is suggestive of mediastinitis and possible rupture
US of neck:
- Low sensitivity
- Not recommended
CT of neck with IV contrast:
- Now preferred imagining modality
- Obtain when x-rays nondiagnostic or to determine exact size and location of abscess noted on x-ray
- Abscess appears as hypodense lesion with peripheral ring enhancement in retropharyngeal space
- Sensitivity: 64 " 100%
- Specificity: 45 " 88%
- Can aid in operative planning, revealing extent of invasion into retro/parapharyngeal spaces
- Unclear if it reliably can distinguish abscess from cellulitis and lymphadenitis
- Due to radiation exposure and need for sedation, CT should only be obtained in young children if x-rays are nondiagnostic
MRI:
- More sensitive than CT
- Also useful for imaging vascular lesions such as jugular thrombophlebitis

Diagnostic Procedures/Surgery

Surgical drainage/needle aspiration should be performed in OR:
- Presence of pus is gold standard for making diagnosis
- Abscess should be completely evacuated
- Pus should be sent for Gram stain and culture
No role for nasopharyngolaryngoscopy

Differential Diagnosis

Tonsillopharyngitis
Epiglottitis
Peritonsillar abscess
Croup
Foreign body
Tracheitis
Meningitis
Retropharyngeal hemorrhage
Dystonic reactions
Cervical osteomyelitis
Dental infections
Mononucleosis
Epidural abscess
Other deep space infection of the neck

Treatment

Pre-Hospital

Keep child in position of comfort:
- Forcing child to sit up or flex neck may occlude airway
Pulse oximetry, cardiac monitor
Supplemental oxygen
Adequate hydration
Suction, endotracheal tube, tracheostomy equipment ready for potential emergent intubation
Airway control will be required for:
- Airway compromise
- Prior to long transport

Initial Stabilization/Therapy

Assess and control airway
Provide supplemental oxygen
IV access:
- Avoid if signs of airway compromise

Ed Treatment/Procedures

Early endotracheal intubation or tracheostomy for patients with respiratory distress or impending obstruction:
- Caution must be used with induction, as sedation medications may lead to relaxation of airway muscles causing complete obstruction
- Rescue airway equipment such as a laryngeal mask airway available, as pharyngeal swelling may make intubation difficult
- Cricothyrotomy may be required if upper airway is obstructed
Surgical consultation (ear/nose/throat if available)
Early administration of IV antibiotics

Medication

Empiric IV antibiotic therapy to cover group A streptococci, S. aureus (including MRSA), and respiratory anaerobes:

Antibiotic tailored to local preferences and susceptibilities
Coverage is narrowed when culture results and sensitivities return
Use of corticosteroids is controversial and recommended only after consultation with ear/nose/throat
Immunocompromised, diabetics, IV drug users, institutionalized patients, and young children (<1 yr) at high risk for MRSA

First Line
Several antibiotic regimens are available:

Clindamycin: 600 " 900 mg (peds: 25 " 40 mg/kg/24 h) IV q8h (max. 4.8 g/d)
Clindamycin + Metronidazole (loading dose 15 mg/kg IV not to exceed 4 g/d followed by 7.5 mg/kg PO/IV)
Penicillin G + Metronidazole
Cefoxitin 1 g IV q6 " 8h/3 " 4 g/d max.
Ticarcillin/Clavulanate 3.1 g IV q4 " 6h
Piperacillin/Tazobactam 3.375 g IV q6h

Second Line
If patients do not respond or there is concern for MRSA:

Vancomycin: 15 " 20 mg/kg (peds: 40 " 60 mg/kg/24 h IV q6 " 8h) IV q12h
Linezolid: 600 mg (peds: 0 " 11 yr: 30 mg/kg/24 h q8h; >12 yr: Adult dose) IV/PO q12h

Follow-Up

Disposition

Admission Criteria

All patients with retropharyngeal abscess should be admitted to the hospital for IV antibiotics and possible surgical drainage
Criteria for surgical drainage:
- Airway compromise or other life-threatening complications
- Large (>2 cm hypodense area on CT)
- Failure to respond to parenteral antibiotic therapy
ICU admission for patients with:
- Airway compromise
- Sepsis
- Altered mental status
- Hemodynamic instability
- Infants and toxic-appearing children
- Major comorbidities

Discharge Criteria
Patients with retropharyngeal abscesses should not be discharged
Issues for Referral
Transfer should be considered if facility does not have the ability to drain infection:

Airway should be stabilized prior to transfer

Pearls and Pitfalls

Diagnosis should be considered in all children who present with fever, stiff neck, or dysphagia:
- High clinical suspicion is required in children, as they present with nonspecific signs and symptoms
Adult cases most often present in the setting of underlying illness, recent intraoral procedures, neck trauma, or head and neck infections
When imaging is nondiagnostic and clinical suspicion remains high, surgery should be consulted
Early surgical consultation and administration of IV antibiotics is essential to prevent complications such as airway compromise and extension into mediastinal structures

Additional Reading

Chow AW. Deep neck space infections. UpToDate February 17, 2012. Available at http://www.uptodate.com/contents/deep-neck-space-infections.
Marx JA, Hockberger RS, Walls RM, et al. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. St. Louis, MO: Mosby; 2010.
Page NC, Bauer EM, Lieu JE. Clinical features and treatment of retropharyngeal abscess in children. Otolaryngol Head Neck Surg. 2008;138:300 " 306.
Reynolds SC, Chow AW. Severe soft tissue infections of the head and neck: A primer for critical care physicians. Lung. 2009;187:271 " 279.
Wald ER. Retropharyngeal infections in children. UpToDate August 17, 2012. Available at http://www.uptodate.com/contents/retro pharyngeal-infections-in-children.

Codes

ICD9

478.24 Retropharyngeal abscess

ICD10

J39.0 Retropharyngeal and parapharyngeal abscess

SNOMED

18099001 retropharyngeal abscess (disorder)

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