Floor of the mouth abscess causing early symptoms of Ludwig angina

Findings

Figure 1: Contrast enhanced axial CT at the level of the hyoid bone demonstrates complex cystic mass with peripheral rim enhancement and adjacent soft tissue reticulation.
Figure 2: Axial CT in bone window demonstrating the left mandibular molar dental extraction site.

Differential diagnosis:
- Branchial cleft cyst
- Neoplasm (squamous cell carcinoma)
- Cystic hygroma
- Dermoid
- Thyroglossal duct cyst
- Laryngocele
- Abscess
- Necrotic node (metastasis)
- Ranula


Diagnosis: Floor of the mouth abscess causing early symptoms of Ludwig angina


In a case of suspected oral cavity infection, the role of imaging is to evaluate the integrity of the airway and to document the presence of gas forming organisms, underlying dental infection, and possibly drainable neck abscess. Reactive or suppurative adenopathy involving the submandibular and submental nodes is commonly seen in association with oral cavity infections. As these nodes receive drainage from the chin, floor of the mouth, and the tongue, foci of infection within these regions should be sought.

Before the antibiotic era, infections at the floor of the mouth dissected inferiorly along the fascial planes into the mediastinum. Ludwig angina is a feared complication of abscess at the floor of the mouth. Ludwig angina is characterized by swelling from a rapidly spreading cellulitis of the sublingual, submental, and submandibular spaces with elevation and edema of the tongue, drooling, potentially leading to airway obstruction. The condition is odontogenic in 90% of cases and arises from the second and third mandibular molars in 75% of cases.

In this case, the patient had undergone left mandibular molar extraction two weeks prior to this presentation. She presented to the ED with mild intermittent airway discomfort and was admitted following the CT. During the incision and drainage in the operating room, the abscess was found to be in direct connection with the mandibular extraction site as the surgeon was able to express pus in the mouth by compressing the neck abscess from outside. Although this case presented early and was treated successfully, airway compromise is the leading cause of death in Ludwig angina.