Poster 027: A Case of Deep Neck Abscess by Which Ring Enhancement of the External Jugular Vein Became an Indicator of the Diagnosis

Abstract

It is well known that contrast-enhanced CT is useful for diagnosis of deep neck abscess. The characteristic findings are: (1) single cystic or multiloculated low-density findings; (2) contrast enhancement of the abscess wall; (3) edema surrounding the abscess; (4) anatomical boundaries that fit the fascial spaces; and (5) air and/or fluid at the center of the abscess. However, little is known about the nature of the inflammatory reaction. Herein, we report an abnormal case of deep neck abscess developing from odontogenic infection. In this case, rapid spread of the inflammation was demonstrated and there was a lack of characteristic CT findings to suggest the formation of abscess. The patient was a 46-year-old woman with swelling in the right parotid region complicated by right inferior alveolar neuroparalysis. The patient’s medical history included diabetes (HbA1C 12%). Although the patient reported oppressive pain in the right parotid region at the first medical examination, the range of swelling was ambiguous because the neck was thick and short. It was only the intraoral view that showed slight redness in the right mandibular first-molar region. The right parotid gland showed diffuse swelling on contrast-enhanced CT, but there were no signs of a clear abscess. However, there was ring enhancement of the right external jugular vein extending for about 11cm from the inferior pole of the parotid gland, and circumferential edema was also noted. The WBC was 15100/ul and CRP was 25 mg/dl. She was given a diagnosis of right mandibular osteomyelitis and cervical cellulites caused by an odontogenic infection of the right mandibular first-molar. Although antimicrobial therapy and blood sugar management were started under hospitalization, there was no reduction of inflammation. Based on the range of ring enhancement of the right external jugular vein, the region was incised and pus was drained from the superficial layer of the cervical fascia. This experience suggests that ring enhancement of the vein was an indicator of abscess on contrast-enhanced CT.