Retropharyngeal abscess

Background

Anatomy of the posterior pharynx.

Infrahyoid deep neck spaces

Neck anatomy at the level of the tongue.

Midline neck anatomy on lateral view.

• Polymicrobial abscess in space between posterior pharyngeal wall and prevertebral fascia
• Adults: Due to direct extension of purulent debris from adjacent site (e.g. Ludwig's angina)
  • More likely to extend into the mediastinum
• Children: Due to suppurative changes within a lymph node (primary infection elsewhere in head or neck)
• Trauma: Direct inoculation (e.g. child falling with stick in mouth)
• Patients may prefer to lay supine to prevent abscess and edematous posterior wall to collapse into airway, so patients should not be forced to sit up

Clinical Features

Bulging of the posterior wall of the oropharynx due to retropharyngeal abscess.

Initial symptoms

• Sore throat (76%)
• Fever (65%)
• Torticollis (37%)
• Dysphagia (35%)

Late symptoms

• Stridor, respiratory distress, chest pain (mediastinitis)
• Drooling, neck stiffness
• Involvement of carotid neurovascular sheath

Complications

• Mediastinitis, sepsis, aspiration from spontaneous abscess formation
• Jugular venous thrombosis, Lemierre's syndrome

Differential Diagnosis

Acute Sore Throat

Bacterial infections

• Streptococcal pharyngitis (Strep Throat)
• Neisseria gonorrhoeae
• Diphtheria (C. diptheriae)
• Bacterial Tracheitis

Viral infections

• Infectious mononucleosis (EBV)
  • Patients with peritonsillar abscess have a 20% incidence of mononucleosis
• Laryngitis
• Acute Bronchitis
• Rhinovirus
• Coronavirus
• Adenovirus
• Herpesvirus
• Influenza virus
• Coxsackie virus
  • Herpangina
  • Hand-foot-and-mouth disease
• HIV (Acute Retroviral Syndrome)

Noninfectious

• Stevens-Johnson Syndrome
• Pemphigus
• Angioedema

Other

• Deep neck space infection
  • Retropharyngeal abscess
  • Ludwig's angina
  • Parapharyngeal space infection
• Peritonsillar Abscess (PTA)
• Epiglottitis
• Kawasaki disease
• Penetrating injury
• Caustic ingestion
• Lemierre's syndrome
• Peritonsillar cellulitis
• Lymphoma
• Internal carotid artery aneurysm
• Oral Thrush
• Parotitis
• Post-tonsillectomy hemorrhage
• Vincent's angina
• Acute necrotizing ulcerative gingivitis

Pediatric stridor

<6 Months Old

• Laryngotracheomalacia
  • Accounts for 60%
  • Usually exacerbated by viral URI
  • Diagnosed with flexible fiberoptic laryngoscopy
• Vocal cord paralysis
  • Stridor associated with feeding problems, hoarse voice, weak and/or changing cry
  • May have cyanosis or apnea if bilateral (less common)
• Subglottic stenosis
  • Congenital vs secondary to prolonged intubation in premies
• Airway hemangioma
  • Usually regresses by age 5
  • Associated with skin hemangiomas in beard distribution
• Vascular ring/sling

>6 Months Old

• Croup
  • viral laryngotracheobronchitis
  • 6 mo - 3 yr, peaks at 2 yrs
  • Most severe on 3rd-4th day of illness
  • Steeple sign not reliable- diagnose clinically
• Epiglottitis
  • H flu type B
    • Have higher suspicion in unvaccinated children
  • Rapid onset sore throat, fever, drooling
  • Difficult airway- call anesthesia/ ENT early
• Bacterial tracheitis
  • Rare but causes life-threatening obstruction
  • Symptoms of croup + toxic-appearing = bacterial tracheitis
• Foreign body (sudden onset)
  • Marked variation in quality or pattern of stridor
• Retropharyngeal abscess
  • Fever, neck pain, dysphagia, muffled voice, drooling, neck stiffness/torticollis/extension

Evaluation

A lateral x-ray demonstrating prevertebral soft tissue swelling (marked by the arrow)

Retropharyngeal abscess on CT

Large retropharyngeal abscess as seen on CT.

CT (transversal view) showing retropharyngeal abscess collection.

• CT neck with IV contrast
  • Gold standard

XR Soft tissue

• Neck in extension at end inspiration
• The prevertebral space should be less than 7mm at C2, 14mm at C6 in children regardless of the age
• The prevertebral space should be less than 22mm at C6 in adults
• The prevertebral space should be less than one-half the width of the corresponding vertebral body
• If equivocal XR, order CT

Management

1. Emergent ENT consult
   • Most patients require I&D
   • Indications for drainage - trismus, rim enhancement on CT
2. Secure airway - care must be taken to minimize contact with abscess as rupture is significant risk
   1. Tracheostomy or fiberoptic intubation may be necessary
   2. CT or MRI may help prepare for method of definitive airway

Antibiotics

• Clindamycin 600-900mg IV OR
• Cefoxitin 2gm IV OR
• Ampicillin/Sulbactam 3g IV

Disposition

• Admit

See Also

• PTA
• Ludwig's Angina
• Pharyngitis