History
In patients presenting with concern for retropharyngeal abscess (RPA), the history is not always straightforward . Symptoms (in decreasing order of incidence) can include the following:
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Fever
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Sore throat
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Dysphagia
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Trismus
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Decreased appetite
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Voice change
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Odynophagia
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Neck pain
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Irritability
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Difficulty in breathing
A review by Grisaru-Soen et al revealed fever (70%) and neck pain (62%) to be the most common symptoms. [9]
Small children with torticollis tend to hold the neck in a nonneutral position and do not turn the head from side to side. Patients may also complain of a muffled voice, a globus sensation, or pain in the back and shoulders upon swallowing. Finally, difficulty in breathing, drooling, or posturing may be an ominous portent of airway obstruction.
The course of RPA can be insidious; in some cases, an upper respiratory illness can precede symptoms by weeks. Accordingly, it is vital to maintain a high index of suspicion, especially in patients with upper respiratory illnesses that appear not to resolve in a normal course or to respond to conventional therapy.
Physical Examination
Most patients with an RPA are febrile upon presentation, and some may even appear toxic and irritable. Tender cervical lymphadenopathy, usually unilateral, is the most common physical finding in these patients. Patients may have decreased or painful neck or jaw range of motion. Some children may also present with a muffled "hot potato" voice (dysphonia).
Upon inspection of the oral cavity, the physician may be able to appreciate a bulge in the posterior pharyngeal wall. This retropharyngeal bulge is typically not in the midline, because of the presence of the raphe that divides the retropharyngeal space.
Patients in respiratory distress or those who present with stridor or drooling have the potential for airway compromise and should be managed expeditiously. Children should also be carefully evaluated for extension of the infection to the carotid sheath or the mediastinum.
Complications
Complications of RPAs arise from mass effect, rupture, or spread. A study of 138 patients over a 10-year period demonstrated mediastinitis to be the most common complication (nine patients); it also demonstrated that younger patients, as well as those with S aureus infections, were at higher risk for complications. [14]
The mass of the abscess in the retropharyngeal space can compress the airway. Because this is the most immediately life-threatening complication of RPA, it must be addressed first, as follows:
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Secure the airway of patients in respiratory distress (stridor or drooling)
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Attempt airway stabilization by first repositioning the head and neck and providing oxygen supplementation
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If repositioning and oxygen supplementation are not successful, provide definitive airway control, which can be accomplished by means of endotracheal intubation or flexible fiberoptic intubation
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Surgical airway intervention (tracheotomy) should be reserved for refractory cases and carried out with the assistance of a pediatric otolaryngologist
Abscess rupture can lead to asphyxiation or aspiration pneumonia. The abscess can rupture spontaneously or iatrogenically during vigorous physical examination or attempted intubation. Chest radiography is indicated to assess for pneumonia after abscess rupture. Abscess rupture requires aggressive airway management, including deep suctioning, broad-spectrum antimicrobial therapy, or both.
Infection can also spread either laterally and posteriorly to adjacent structures in the neck, or it can progress inferiorly to the mediastinum. Lateral spread can involve the carotid sheath, where it can cause vascular compromise. One case study detailed a pseudoaneurysm of the internal carotid artery secondary to RPA. [15]
Posterior spread of infection can also affect the cervical spine. Osteomyelitis necessitates long-term antibiotic therapy; erosion of ligaments can cause subluxation and subsequent spinal cord injuries. Destruction of the transverse ligament of the atlas has been known to cause atlanto-occipital dislocation.
Inferior spread of infection can cause several life-threatening complications. Chest radiography is indicated in the initial workup when concern is elicited. Inflammation in the mediastinum can cause mediastinitis, purulent pericarditis, pericardial tamponade, bronchial erosion, and mediastinal abscess. Spread to the adjacent pleura can cause pleuritis, pyopneumothorax, or empyema. In addition to antibiotic therapy, drainage of purulence via pericardiocentesis, pericardial window, chest tube thoracostomy, or open thoracotomy may be necessary.
Finally, infection also can evolve into overwhelming sepsis or necrotizing fasciitis in the neck or mediastinum.
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Schematic of neck deep space anatomy, as illustrated in lateral and cross-sectional views. Fascial planes (see color key) surround potential spaces. Anteriorly, retropharyngeal space is bounded by buccopharyngeal fascia, which invests pharynx, trachea, esophagus, and thyroid; posteriorly by alar fascia; and laterally by carotid sheaths and parapharyngeal spaces. Retropharyngeal space extends from skull base to mediastinum at level of tracheal bifurcation. Note danger space located between alar fascia and prevertebral fascia.
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Plain lateral neck x-ray. Top radiograph reveals widening of soft tissues, with anterior airway displacement. Careful examination of this film also reveals gas in soft tissues. Bottom radiograph reveals soft tissue widening at C2.
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Contrast axial CT scan demonstrates left-side retropharyngeal abscess with central hypoattenuation.
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Contrast sagittal CT scan demonstrates central hypodensity with prevertebral soft-tissue stripe widening and oropharyngeal air column narrowing consistent with retropharyngeal abscess formation.
