Wisdom Tooth's Revenge: Retropharyngeal Abscess and Mediastinitis after Molar Tooth Extraction

Abstract

Retropharyngeal abscess is potentially associated with high morbidity and mortality as a result of its direct anatomical connection with the mediastinum. Therefore, knowledge of the relevant anatomy is essential for recognizing the presence and extent of disease in a timely manner. In this case report, we aim to review the pertinent anatomy and patterns of spread of infection from a full blown deep neck space infection to result in mediastinitis and empyema.

Keywords: CT; Case Report; Deep neck spaces; Esophageal fistula; Retropharyngeal abscess.

Figure 1

24 year old female with deep neck abscesses seen on this outside facility CT performed 2 weeks before her presentation to the emergency room. Findings: (a) Contrast enhanced neck CT at the suprahyoid neck level demonstrates multiple, rim-enhancing, interconnected fluid collections within the deep spaces of the neck, including mucosal pharyngeal [M], retropharyngeal/danger [R/D], prevertebral [Pr], and bilateral carotid spaces (C). A suppurative lymph node [LN] is also present. Note the obliteration of the right piriform recess due to soft tissue edema within the mucosal pharyngeal space. The left piriform recess [Pi] is labeled for reference. (b) Contrast enhanced neck CT at the infrahyoid neck level. Rim enhancing fluid collections are present within the visceral [V] and retropharyngeal/danger [R/D] spaces, as well as in between the fasciae of the infrahyoid neck muscles [I]. Th: Thyroid gland. Technique: GE Lightspeed RT 16 CT Scanner, 120 kV, 46 mAs, 2.5 mm slice thickness, axial soft tissue window, with 98 ml of Omnipaque 300.

Figure 2

24 year old female with mediastinitis and empyema secondary to deep neck space abscesses. Findings: Note the heterogeneous fluid collection within the mediastinum (black plus signs, 2a-c), extending from the danger space (asterisk, 2b). The black arrow in 2b depicts the path of spread. In addition there is a large, multiloculated left pleural fluid collection (white plus signs, 2a and 2c) in contiguity with the mediastinal fluid collection. Technique: Siemens SOMATOM Definition AS Plus CT Scanner, 120 kV, 229mAs. (a) 1.5 mm slice thickness, coronal soft tissue window. (b, c) 1.5 mm slice thickness, sagittal soft tissue window, with 25 ml of Omnipaque 350.

Figure 3

24 year old female with retropharyngeal abscess. Findings: (a) Fluoroscopic imaging of the neck during ingestion of oral water soluble contrast demonstrates passage of contrast into the retropharyngeal space [asterisk] through a fistula [arrows] at the posterior oropharyngeal wall. The surgical drain [SD] and hospital gown buttons [B] overlie the neck. (b) CT correlation of the retropharyngeal abscess, extending from the posterior wall of the oropharynx [OP] inferiorly to at least T3 vertebral level. The CT image is from the day of the admission. E: Epiglottis. OP: Oropharynx. Technique: (a) Philips EasyDiagnost Eleva DRF, lateral view. (b) Siemens SOMATOM Definition AS Plus CT Scanner, 100 kV, 193mAs, 2 mm slice thickness, sagittal soft tissue window, with 25 ml of Omnipaque 350.

Figure 4

24 year old female with retropharyngeal abscess. Findings: 1 week follow-up fluoroscopic examination of the neck during ingestion of oral contrast demonstrates absence of contrast passage into the retropharyngeal space, suggesting healing of the fistula. The air-containing retropharyngeal collection [asterisks] seen posterior to the esophagus is smaller in size, suggesting abscess resolution in progress. A nasogastric tube [NGT] is in place. The surgical drain [SD] and hospital gown buttons [B] overlie the neck. E: Epiglottis Technique: Philips EasyDiagnost Eleva DRF, lateral view.

Figure 5

Schematic representation of the fasciae of the infrahyoid neck and associated deep neck spaces. All of the deep neck spaces shown in this figure extend to at least upper mediastinum. These structures have the same configuration in the suprahyoid neck except for the visceral space, where it is replaced by the mucosal pharyngeal space. 1: Visceral space. Contains thyroid, trachea, and esophagus. Extends into mediastinum. 2: Retropharyngeal space. Contains fat (also lymph nodes in children). Extends into upper mediastinum. 3: Danger Space. Potential space, normally does not have any contents. Extends to the diaphragm. 4, 5: Perivertebral space, prevertebral (4) and paraspinal (5) components. Contain vertebrae and associated arteries, veins, nerves and muscles. Extends along the vertebral column to the coccyx. 6: Carotid space. Contains carotid arteries, internal jugular veins and cranial nerves 9–12. Extends into the aortic arch.