SA-CME SA–CME Information Imaging Acute Face and Neck Infections Description Authors Many acute infectious conditions of the face and neck re- Blair A. Winegar, MD, is an Assistant Professor in the De- sulting from common sources, such as pharyngitis, dental partments of Medical Imaging, Ophthalmology and Vision infection, and penetrating trauma, are evaluated in the emer- Science, and Neurosurgery; Ethan A. Neufeld, MD, is an As- gency department. The clinical features of these conditions sistant Professor in the Department of Medical Imaging; and overlap, and clinical evaluation is often insufficient to localize Dr. Kubal is a Professor in the Departments of Medical Imag- or determine the extent of infection within the deep spaces of ing and Neurosurgery, all at the University of Arizona College the neck. of Medicine, Tucson, AZ. This article showcases the classic imaging features and lo- cations of a variety of acute face and neck infections encoun- Target Audience tered in the emergency department. In addition, the imaging • Radiologists findings of potentially life-threatening complications, such as • Related Imaging Professionals mediastinitis resulting from retropharyngeal abscess and sep- tic pulmonary emboli resulting from Lemierre syndrome, are System Requirements described. In order to complete this program, you must have a com- In the emergency setting, the radiologist’s ability to cor- puter with a recently updated browser and a printer. For as- rectly identify and categorize acute face and neck infections sistance accessing this course online or printing a certificate, and their complications is paramount to direct appropriate sur- email [email protected]. gical and medical management. Instructions Learning Objectives This activity is designed to be completed within the des- After completing this activity, the participant will be able to: ignated time period. To successfully earn credit, participants • Describe pathophysiology, clinical features, and treat- must complete the activity during the valid credit period. To ments for a variety of acute face and neck infections con- receive SA–CME credit, you must: fronted in the emergency department; • Discuss the classic imaging findings and locations of fre- 1. Review this article in its entirety. quently encountered acute face and neck infections; and 2. Visit www.appliedradiology.org/SAM2. • Recognize potential complicating features of acute face 3. Login to your account or (new users) create and neck infections which may be detected on imaging. an account. 4. Complete the posttest and review the discussion Accreditation/Designation Statement and references. The Institute for Advanced Medical Education is accredited 5. Complete the evaluation. by the Accreditation Council for Continuing Medical Educa- 6. Print your certificate. tion (ACCME) to provide continuing medical education for physicians. Estimated time for completion: 1 hour The Institute for Advanced Medical Education designates this Date of release and review: May 1, 2020 journal-based CME activity for a maximum of 1 AMA PRA Cat- Expiration date: April 30, 2022 egory 1 Credit™. Physicians should only claim credit commen- surate with the extent of their participation in the activity. Disclosures These credits qualify as SA-CME credits. No authors, faculty, or any individuals at IAME or Applied Radiology who had control over the content of this program have any relationships with commercial supporters. © May–June 2020 www.appliedradiology.com APPLIED RADIOLOGY n SA-CME Imaging Acute Face and Neck Infections Blair A Winegar, MD; Ethan A Neufeld, MD; Wayne S Kubal, MD variety of acute infectious dis- A B orders of the face and neck, resulting from such common Asources as pharyngitis, dental infection, and penetrating trauma, may present to the emergency department. Clinical lo- calization of such infections, especially those involving the deep neck, is lim- ited. In one series of patients with deep neck involvement, clinical examination localized the space involved in only 42.9% of cases.1 Accurate characteri- zation of infections can determine the FIGURE 1. Dental abscess. (A) Coronal contrast-enhanced CT (CECT) on bone algorithm most appropriate therapy; ie, aspiration/ demonstrates right maxillary molar dental caries and periapical lucency (arrowhead) compati- drainage versus antibiotic therapy. ble with dental abscess. (B) Axial CECT shows a rim-enhancing fluid collection along the right buccal surface of the maxillary alveolar ridge, compatible with an associated subperiosteal Nevertheless, despite widespread ac- abscess of dental origin (arrow). cess to antibiotics, face and neck infec- tions still present significant morbidity periapical abscesses. Infection can also fascia, which encompasses the muscles and mortality. Potentially life-threat- arise from the tissues along the mar- of mastication and a portion of the pos- ening complications, including airway gins of the tooth roots, and is known as terior mandible. Dental infections of obstruction, mediastinitis, and septic a periodontal abscess. Such abscesses the posterior mandibular molars may emboli, are reported in 10-20% of deep can result in focal cortical destruction breach into the masticator space, result- neck infections.2,3 Emergency radiolo- of the alveolar ridge and extend into the ing in abscess formation that may clini- gists play a critical role in diagnosing, adjacent subperiosteal and extraosseous cally present as trismus. localizing, characterizing, and identi- spaces, resulting in facial cellulitis. On CT, a rim-enhancing fluid col- fying the complications resulting from On computed tomography (CT), os- lection along the posterior margin acute face and neck infections. seous lucency around the tooth root of the mandible close to the muscles apex suggests a periapical abscess (Fig- of mastication is compatible with a Dental Abscess ure 1A).4 Rim-enhancing fluid collec- masticator space abscess (Figure 2A). Dental caries, broken teeth, or peri- tions and associated inflammatory fat Imaging should cover the superior ex- odontal disease can predispose teeth stranding in the adjacent buccal space tent of the temporalis muscles, as the and adjacent soft tissues to bacterial are compatible with extension of infec- masticator space continues superiorly infections. Dental abscesses, focal col- tion (Figure 1B). An osseous breach of above the zygomatic arch to the pari- lections of pus associated with bacterial the alveolar ridge between the periapical etotemporal scalp (Figure 2B).5 The infection, occur most commonly adja- abscess and adjacent subperiosteal or ex- ipsilateral mandibular teeth should cent to the tooth root tip, and are termed traosseous abscess is frequently present. be assessed for underlying dental ab- scess. Additional potential infectious Affiliations: University of Arizona Masticator Space Abscess sources include septic arthritis of the College of Medicine, Tuscon AZ. The The masticator space is contained by temporomandibular joint and coales- authors declare no conflicts of interest. the superficial layer of the deep cervical cent mastoiditis. © 28 n APPLIED RADIOLOGY www.appliedradiology.com May–June 2020 IMAGING ACUTE FACE AND NECK INFECTIONS SA-CME A B FIGURE 2. Masticator space abscess. (A) Axial CECT demonstrates a loculated rim-enhancing fluid collection along the left mandibular ramus and muscles of mastication, compatible with masticator space abscess (arrow). (B) Axial CECT shows extension of this abscess into the supra- zygomatic masticator space along the left temporalis muscle (arrowhead). A B FIGURE 3. Ludwig angina. (A) Axial CECT shows extensive inflammatory stranding and phlegmon within the sublingual spaces (arrowheads). (B) Coronal CECT demonstrates inflammatory stranding in the submandibular spaces (arrows) in addition to the sublingual spaces (arrow- heads) in this case of Ludwig angina. Ludwig Angina ing and swelling within the bilateral lucency with potential lingual cortical Ludwig angina is a potentially life- sublingual spaces in the floor of mouth breakthrough involving a second or third threatening bacterial cellulitis of the sub- (Figure 3A).7 Additional inflammatory mandibular molar suggests the inciting lingual and submandibular spaces that stranding in the fat of the submandibular dental abscess. can result in acute airway compromise. spaces inferior and lateral to the mylohy- This infection is most commonly the oid muscles is typically present (Figure Odontogenic Sinusitis result of extension of infection from an 3B). Rim-enhancing fluid collections Dental abscesses adjacent to the roots odontogenic source.6 On CT, Ludwig an- compatible with abscesses occasionally of the maxillary premolars and molars gina demonstrates inflammatory strand- may be seen. Presence of a periapical may result in inflammatory mucosal © May–June 2020 www.appliedradiology.com APPLIED RADIOLOGY n 29 SA-CME IMAGING ACUTE FACE AND NECK INFECTIONS FIGURE 4. Odontogenic sinusitis. Coronal CT shows a left maxillary FIGURE 5. Tonsillitis. Axial CECT demonstrates bilateral enlarged molar periapical lucency with dehiscence into the left maxillary sinus palatine tonsils (arrow) with linear enhancing striations (“tiger (arrow). The adjacent left maxillary sinus is filled completely indicating stripe” appearance) which touch in the midline (“kissing tonsils”) in odontogenic sinusitis. this case of tonsillitis secondary to infectious mononucleosis. unit pattern of obstructive paranasal ria gonorrhoeae,