Emergency Head and Neck Radiology: Neck Infections

Jason A. McKellop, MD; Suresh K. Mukherji, MD, FACR


Appl Radiol. 2010;39(7):23-29. 

In This Article

Sublingual Space Infections

The sublingual space (SLS) is located inferior to intrinsic muscles of the oral tongue, lateral to the genioglossus-geniohyoid complex and superomedial to the mylohyoid muscle. Anteriorly, it is related to the mandible. Posteriorly, the SLS communicates with the submandibular space (SMS) with no fascia separating these spaces.

Sublingual Space Abscess

Abscesses originating in this space are usually due to sublingual or submandibular duct stenosis or calculus disease. Dental infection or mandibular osteomyelitis may also extend into the SLS. The most commonly encountered organisms in SLS abscess formation are S. aureus and Streptococcus viridans.

Clinically, patients with SLS abscess usually present with pain, tenderness and swelling in the anterior floor of the mouth. There may be a history of salivary colic, recent dental disease or dental manipulation. Treatment of an SLS abscess should commence with antibiotic therapy followed by surgical drainage.

CT shows an enhancing mass involving the SLS associated with subcutaneous streaking and thickening of the platysma muscle. The genioglossus-geniohyoid complex is often displaced medially or across the midline (Figure 4). If an SMS component is present, this abscess may track into parapharyngeal space, where further spread can take place in the craniocaudal axis. Infection may also spread to the medial pterygoid or masseter muscles.

Figure 4.

Sublingual space abscess. Axial contrast-enhanced CT (A) shows an abscess involving the left sublingual space (arrow). The bone algorithm (B) shows that the cause of the abscess is due to a "rotten" tooth (arrow).

MR imaging is rarely used for inflammatory disease involving the floor of the mouth. A floor-of-the-mouth abscess shows the typical enhancing mass on T1W images and high signal intensity on T2W images. In contrast-enhanced images, a central area of no enhancement, indicating pus collection, can readily be demonstrated. Mandibular marrow edema is more readily demonstrated on MR as intermediate signal tissues replacing high signal intensity fat on T1W images.

Ludwig's Angina

The term "Ludwig's angina" refers to cellulitis involving the floor of the mouth. This infection is usually due to streptococcus or staphylococcus species. Patients usually present with pain, tenderness and swelling of the mouth floor. The infection is usually precipitated by an odontogenic infection.[4] In neglected cases, Ludwig's angina may spread inferiorly through fascial planes into the mediastinum. Hence, some patients may present with chest pain.

Securing a patent airway is an important aspect of the management of this entity along with IV antibiotics and, if necessary, surgical drainage of secondary abscesses.[5]

Contrast-enhanced CT shows swelling of the floor of the mouth (Figure 5). This finding is frequently associated with streaky changes in the adjacent subcutaneous fat and thickening of the overlying platysma muscle. Enlargement of the submental or submandibular lymph nodes may also be seen. In late cases, pus or gas formation may take place and the airway may be compressed.

Figure 5.

Ludwig's angina. Contrast-enhanced CT (A) shows multiple abscesses (arrows) in the sublingual space. This patient also had edema of the larynx, as demonstrated by thickening of the left aryepiglottic fold (arrow).

Contrast-enhanced MR images show a thickened floor of the mouth with strong enhancement. On T2W images, diffuse high signals are evident in the floor of the mouth and adjacent soft tissues.


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