Retropharyngeal cellulitis and abscesses are often secondary to polymicrobial infection; the most commonly encountered species are Streptococcus (beta-hemolytic and pyogenes), S aureus, H influenza, and Klebsiella pneumoniae, along with several others (eg, Neisseria, Peptococcus, Bacteroides, and Fusobacterium).
Despite its name, H influenzae is not a virus but a Gram-negative bacillus commonly found to be the cause of pneumonia, meningitis, and skin-soft tissue infections, especially in the pediatric population. Prior to routine vaccination of Hib in 1985, as many as 1 in 200 children developed this disease before age 5 years; it has since diminished considerably.[4,5,6] Most cases in adults are nontypable species seen in the context of an immunocompromised state (eg, diabetes, alcoholism, neoplasm) and/or longstanding lung disease (eg, chronic obstructive pulmonary disease, smoking).
Imaging modalities (plain radiography and CT scanning) help confirm the diagnosis, exclude other diagnoses and/or confounding factors, and trend progress of treatment. When imaging these patients, one must be familiar with the potential spaces lying behind the oropharynx as that helps to localize the infection and predict the potential spread if not adequately treated. Immediately behind the visceral fascia, as one goes beyond the posterior pharynx, lies the retropharyngeal space, specifically between the middle layers of the deep cervical fascia. That is followed by the alar fascia of the prevertebral fascia. The retropharyngeal space extends from the base of the skull inferiorly to C7 or T1, with the carotid sheath running laterally. The space contains lymph nodes that regress after childhood (usually after age 4 years). This might explain the low incidence of retropharyngeal abscess development in adults. Beyond this space, one encounters the prevertebral fascia and space, followed by the vertebral bodies.
In one study, lateral neck radiographs were abnormal in as many as 86% of presentations. Findings include swelling in the retropharyngeal space; the most commonly quoted figures are >7 mm at the level of C2 and 22 mm at the level of C6, regardless of age. Of note, the advancement of CT technology and resolution capabilities has made it a very useful modality, helping to differentiate cellulitis in the retropharyngeal space from abscess formation and visualize the extent of the disease. It is also a helpful planning tool for the surgeon. Contrast enhancement has excellent sensitivity (more than 90%); however, several reviews found a significantly poor specificity (as low as 60%), with difficulty differentiating lymphadenopathy from abscess formation or cellulitis. Findings on CT include cavitary ring enhancement, air-fluid levels, and development of subcutaneous air.
Laboratory findings (ie, inflammatory markers such as leukocytosis and an elevated C-reactive protein) generally don't mirror the extent or severity of disease in minor-to-moderate cases and should generally be reserved for severe cases. Local cultures are useful for narrowing antibiotic coverage once speciation becomes available. Morbidity and mortality are usually secondary to complications from the predicted course of extension of infection via the fascial planes: epidural abscesses, cranial nerve dysfunction, cavernous venous sinus thrombosis, mediastinitis, and spread into the vasculature (carotid artery or jugular vein), as well as inflicting mass effect on the airway (as seen in this case).
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Cite this: Alexander B. Norinsky, Andrew Caravello, James Espinosa. An Adopted 43-Year-Old With Bad Breath, Dyspnea, Dysphagia - Medscape - Jul 14, 2022.