14-32: Retropharyngeal Abscess

Clinical Summary

Retropharyngeal abscess (RPA) usually presents with fever, difficulty swallowing, excessive drooling, sore throat, changes in voice, or neck stiffness. Limitation of neck movement on examination, especially with hyperextension, or torticollis will often be seen. The stiff neck may mimic meningitis. The characteristic retropharyngeal edema is a result of cellulitis and suppurative adenitis of the lymph nodes located in the retropharyngeal space between the buccopharyngeal fascia and the alar fascia. It is seen on a soft-tissue lateral x-ray of the neck as prevertebral soft-tissue thickening. The RPA may be preceded by an upper respiratory infection, pharyngitis, otitis media, or a wound infection following a penetrating injury to the posterior pharynx. The differential diagnosis includes pharyngitis, acute laryngotracheobronchitis, epiglottitis, membranous (bacterial) tracheitis, cervical adenitis, infectious mononucleosis, peritonsillar abscess, foreign-body aspiration, and diphtheria.

Management and Disposition

RPA requires immediate assessment of the airway with establishment of a definitive airway if physical exam indicates progressive upper airway obstruction. The most common pathogens that cause RPA are group A Streptococcus, S aureus, MRSA, and respiratory anaerobes. Antibiotic coverage should be initiated immediately (clindamycin or a β-lactamase–resistant penicillin in areas where S aureus remains susceptible to methicillin). Analgesia should be administered as needed. Radiologic evaluation includes soft-tissue lateral neck x-ray and neck CT with contrast to define the extent of infection. In the absence of airway obstruction, medical treatment with IV antibiotics for 24 to 48 hours is first-line therapy. If impending obstruction is present or the infection is unresponsive to IV antibiotic therapy, needle aspiration or incision and drainage should be performed in the operating room. These patients require hospitalization and immediate otolaryngologic or surgical consultation.

Pearls

1. On lateral soft-tissue x-ray of the neck, the prevertebral soft tissue can measure up to 7 mm in width at the level of C2. At C6, it can measure up to 14 mm in width. This represents approximately one-half the width of the corresponding vertebral body.

2. The prevertebral soft tissue may appear falsely enlarged during neck flexion or crying.

3. The peak incidence occurs in 3- to 5-year-olds. It is rare beyond 6 years of age as the retropharyngeal lymph nodes involute.

4. RPAs in older patients most commonly arise as a complication of trauma or an immunocompromised state.

5. Children with severe RPA should be treated as an impeding airway emergency and remain undisturbed while preparing for airway control, preferably in the operating room.