IS case 526: Retropharyngeal abscess
Imaging Sciences URMC 2010
Publication Date: 2010-09-10
Patient is a 65-year-old male seen for a retropharyngeal mass.
Retropharyngeal abscesses are typically preceded by upper respiratory tract infections, middle ear infections or pharyngitis, with contiguous spread to the lymph nodes of the retropharyngeal space. It is most commonly a disease of young children. The retropharyngeal space normally only contains fat and lymph nodes. Its anterior border is the buccopharyngeal fascia and the posterior border is the prevertebral fascia. Lymph nodes of the retropharyngeal space drain the nasopharynx, nasal passage, middle ear and palatine tonsils. Infection from any of these sites can spread to the retropharyngeal space. Retropharyngeal cellulitis and retropharyngeal abscesses demonstrate similar imaging findings. Although retropharyngeal abscesses are less common, differentiation between abscess and cellulitis is important given different management strategies (abscess drainage) and increased risk of complications with retropharyngeal abscesses. The more common of the severe complications of retropharyngeal abscess include: airway compromise secondary to mass effect; descending mediastinitis; and jugular vein thrombosis.
On radiography of the soft tissues of the neck, prominence of the prevertebral soft tissues should raise suspicion for retropharyngeal cellulitis/abscess in the appropriate clinical setting. This is not to be confused with "pseudo-thickening", which can be seen in a flexed neck. Helpful differentiation between pseudo-thickening and true thickening of the retropharyngeal space is apex anterior convexity of the retropharyngeal soft tissue and mass effect on adjacent structures. The presence of air in the soft tissues is diagnostic of an abscess. CT can be preformed to characterize the extent of disease and to differentiate between cellulitis and a drainable abscess. CT findings include retropharyngeal soft tissue thickening with mass effect, obliteration of fat planes and a low attenuation complex fluid collection with an enhancing rim.
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