ENT · Deep Neck Infections
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Most common in children 2-4 years old after a URI, often polymicrobial with Group A //Streptococcus// and anaerobes.
Presents with high fever, muffled "hot potato" voice, severe pain with neck extension, drooling, and stridor.
Lateral neck radiograph shows a widened prevertebral space (>7 mm at C2 or >14 mm at C6 in children).
CT neck with IV contrast is the gold standard, showing ring enhancement and distinguishing abscess from cellulitis.
Protect the airway first: do not agitate a child with stridor as it may precipitate complete airway obstruction.
First-line antibiotics are ampicillin-sulbactam or clindamycin, with surgical I&D for large or airway-threatening collections.
Untreated infection can track downward causing acute necrotizing mediastinitis or fatal airway obstruction.
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A 3-year-old boy presents with 2 days of high fever, refusal to eat, and drooling after a recent upper respiratory infection. He holds his neck stiffly and cries when asked to extend it, and his voice is muffled. Lateral neck radiograph taken in extension shows widening of the prevertebral soft tissue to 12 mm at C2.
Which of the following imaging studies will best confirm the diagnosis?
CT of the neck with IV contrast.
CT neck with contrast is the gold standard for retropharyngeal abscess, distinguishing a true ring-enhancing abscess from cellulitis and guiding the need for surgical drainage. The widened prevertebral space, hot-potato voice, and pain with neck extension are classic, but airway protection always takes priority.
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Etiology / Epidemiology
Most common in children 2-4 years old following an upper respiratory infection, otitis media, or posterior pharyngeal trauma. Polymicrobial infection often driven by Group A //Streptococcus//, Staphylococcus aureus, and respiratory anaerobes.
Clinical Manifestations
Presents with high fever, severe throat pain, neck stiffness with extension, and muffled "hot potato" voice. Classic triad includes torticollis, drooling, and stridor.
Diagnosis
Lateral neck radiograph shows widened prevertebral space (>7 mm at C2 or >14 mm at C6 in children). CT neck with IV contrast is the gold standard to differentiate true abscess from cellulitis.
Treatment
Protect the airway first, then initiate IV antibiotics like ampicillin-sulbactam or clindamycin. Airway compromise or large collections require immediate surgical incision and drainage.
Prognosis
Excellent with prompt treatment, but untreated cases risk downward tracking causing acute necrotizing mediastinitis or airway obstruction.
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Epidemiology & Etiology
Primarily affects children aged 2-4 years because retropharyngeal lymph nodes typically atrophy after age 4-5. It is often preceded by a recent upper respiratory infection, acute otitis media, or penetrating posterior pharyngeal trauma (e.g., falling with a lollipop in the mouth). The etiology is typically polymicrobial, driven by Group A //Streptococcus// (Streptococcus pyogenes), Staphylococcus aureus (including MRSA), and oral anaerobes like Fusobacterium. In adults, it is rare and usually secondary to penetrating trauma (e.g., fishbone ingestion) or dental infections.
Pertinent Anatomy
The retropharyngeal space lies between the buccopharyngeal fascia anteriorly and the alar fascia posteriorly. It extends from the base of the skull down to the superior mediastinum at the level of T1-T2. Because this space communicates inferiorly with the chest cavity, uncontrolled infections can track downward causing life-threatening mediastinitis.
Pathophysiology
An antecedent URI or localized trauma introduces pathogens into the pharyngeal mucosa. Lymphatic drainage carries the bacteria to the retropharyngeal lymph nodes (nodes of Rouvière), causing suppurative lymphadenitis. The infected nodes undergo necrosis and liquefaction, forming a focal collection of pus. This expanding abscess mass exerts direct mechanical pressure on the anterior pharynx and larynx, leading to airway obstruction and severe dysphagia.
Clinical Manifestations
Patients typically present toxic-appearing with high fever, severe dysphagia, and a muffled "hot potato" voice. Physical exam classically reveals cervical lymphadenopathy, neck stiffness (specifically severe pain with neck extension), and torticollis. A bulging of the posterior pharyngeal wall may be visible, though examination should be cautious to avoid abscess rupture and subsequent aspiration. Red flag symptoms requiring immediate intervention include drooling, tripod positioning, and stridor, which signal impending airway collapse.
Diagnosis
Initial evaluation often utilizes a lateral neck radiograph taken during inspiration and neck extension. A positive radiograph demonstrates a widened prevertebral space: >7 mm at C2 or >14 mm at C6 in children (or >22 mm at C6 in adults). The definitive gold standard is a CT neck with IV contrast, which reveals a hypodense fluid collection with ring enhancement and differentiates a true abscess from retropharyngeal cellulitis. Blood cultures and throat swabs should be obtained before initiating antimicrobial therapy.
Treatment
The paramount initial step is securing the airway; do not agitate a child with stridor as it may precipitate complete airway obstruction. For small abscesses without respiratory compromise, a trial of IV antibiotics with ampicillin-sulbactam or clindamycin (plus vancomycin or linezolid if MRSA is suspected) is first-line. Surgical incision and drainage is the definitive treatment for large abscesses (>2.5 cm on CT), lack of clinical improvement after 24-48 hours of IV antibiotics, or any signs of airway compromise.
Prognosis
Most patients recover fully with appropriate antibiotic therapy and timely surgical drainage. However, delayed recognition can lead to devastating complications such as mediastinitis due to inferior tracking of the infection. Other severe sequelae include aspiration pneumonia from spontaneous rupture, carotid artery erosion, and internal jugular vein suppurative thrombophlebitis (Lemierre syndrome).
Differential Diagnosis
1. Epiglottitis: Presents with rapid-onset drooling, dysphagia, and distress, but lateral X-ray shows the classic thumbprint sign rather than prevertebral widening.
2. Peritonsillar Abscess: Features severe throat pain and a hot potato voice, but swelling is asymmetric, located anterior to the tonsils, and causes uvular deviation.
3. Croup: Viral infection causing inspiratory stridor and a barking cough, with a steeple sign on AP neck X-ray and no severe dysphagia.
4. Bacterial Tracheitis: Presents like severe, toxic croup that does not respond to racemic epinephrine, but lacks a widened prevertebral space on imaging.
5. Meningitis: Shares fever and neck stiffness (nuchal rigidity), but lacks pharyngeal bulging, stridor, or localized throat pain.