Retropharyngeal abscesses: A clinical and radiologic correlation

Objective: This study evaluates the efficacy at our centre of the lateral neck x-ray and the computed tomography (CT) scan in differentiating retropharyngeal cellulitis from abscess in retropharyngeal space inflammatory process. Method: We reviewed the medical records of 37 patients with the diagnosis of retropharyngeal abscess or cellulitis hospitalized at the Centre Universitaire de Sante de l'Estrie in Sherbrooke between 1986 and 1997. Patients with a positive drainage at surgery were considered as retropharyngeal abscess and the rest as cellulitis. We measured the sensitivity, specificity, and positive and negative predictive values for the lateral neck x-ray and CT scan. Demographic and clinical data were also extracted for each patient. Results: Twenty-five patients were classified as retropharyngeal cellulitis and only six patients as retropharyngeal abscess, although 13 patients went to the operating room for drainage. Results for the sensitivity and specificity were 80% and 100% for the lateral neck x-ray and 100% and 45% for the CT scan. Positive and negative predictive values for lateral neck x-ray were 100% and 94%, respectively. Forty percent and 100% were the values calculated for the CT scan. Clinical data were consistent with what has been reported in the literature. Conclusion: CT scan is helpful in the management of retropharyngeal abscess but has limits in differentiating cellulitis and abscess. Lateral neck x-ray was found to be very specific when the air sign was present.