Odontogenic epidural abscess

Case contributed by Michael Durkin

Presentation

Patient is a 15 year old female presenting with fevers and facial swelling around left mandible.

Patient Data

Age: 15 years
Gender: Female

Pantomogram

x_ray

Dental caries noted #3 13 19 30. Apical rarefying and sclerosing osteitis on tooth 19 and 30 in the mandible

Day 1

mri

Note edema in the left masticator space.

Peripherally enhancing collection with central T1 hypo intensity that demonstrates diffusion restriction and medial/lingual aspect of the mandible measuring approximately 2.9cm x 1.6cm x 1.5cm. There is surrounding T2 hyper intensity as well as swelling in the soft tissues centered at the angle of the left mandible, involving the submandibular regions. There are prominent sub centimeter left greater than right cervical lymph nodes. There is suggestion of mild left peri-orbital edema, without abnormal enhancement. 

There is a right maxillary sinus mucus retention cyst. The phayrnx and trachea appear normal. The right parotid and thyroid glands appear normal.

Day 2

ct

There is redemonstration of a heterogeneous hypo-dense collection along the lingual surface of the posterior mandibular body which measures 3.4 × 1.3x 2.6 cm. There is mild regional inflammatory stranding including along the left parotid gland with scattered asymmetrically prominent regional lymph nodes. Multiple scattered peri-apical inflammatory lesions and dental caries are noted with subtle cortical disruption. The facial bones, including the orbits and paranasal sinuses are intact without evidence of fracture. A mucus retention cyst or polyp is noted in the right maxillary sinus however the paranasal sinuses are otherwise normally aerated. The mastoid air cells and middle ear cavities are normally aerated. The orbital contents appear normal.

Day 13

mri

There is a left orbital intraconal rim-enhancing fluid collection measuring up to 1.0 cm that abuts the left optic nerve with surrounding stranding/inflammatory changes. There is asymmetric edema and enhancement involving the left lateral and inferior rectus muscles, There is redemonstration of a 4.0 cm rim-enhancing collection along the floor of the anterior cranial fossa, extending to the left middle cranial fossa rim-enhancing collection with associated regional dual thickening. There is asymmetric fullness and enhancement of the left cavernous sinus, The collection abuts the left orbital apex/canalicular and prechiasmatic segments of the left optic nerve, There is prominent adjacent edema in the left greater than right frontal lobes with regional mass effect. There is up to 8 mm rightward midline shift at the level of the anterior inter-hemispheric fissure. There is suggestion of trace inflammatory changes and enhancement in the left retrobulbar fat, Otherwise, the right ocular globe, optic nerve, and extra-ocular muscles appear normal, Post-surgical changes are seen related to left submandibular and masticator space abscess drainage with regional Penrose drain and surrounding edema/enlargement of the muscles of mastication. There is asymmetric subtle edema and enhancement along the left parotid gland.

Day 28

mri

The superior sagittal sinus, torcular herophili, transverse sinuses, sigmoid sinuses and visible internal jugular veins are normal in caliber and show bright flow signal. The venous structures opacity normally; no filling defect is visible. Epidural abscess along the floor of the left anterior cranial fossa has markedly decreased in size with persistent regional dural enhancement and cerebral edema/cerebritis. Improved, though persistent, left retro-orbital cellulitis is noted. There are redemonstration of post-surgical changes related to left submandibular and masticator space abscess drainage, with persistent myositis related to the muscles of mastication.

There is redemonstration of postsurgical changes related left frontal craniotomy with mildly decreased left fronto-temporal edema and effacement of the left lateral ventricle; now with approximately 3 mm leftward midline shift (previously 6 mm). Epidural abscess along the floor of the left anterior cranial fossa has decreased in size, now measures 6-mm. Regional left frontal and anterior temporal and right inferior frontal lobe edema is noted. There is dural enhancement along the left anterior and middle cranial fossa with extension to the orbital apex and left foramen ovale, and possibly left cavernous sinus. There is also mild dural enhancement of the right inferior frontal lobe. Improved, though persistent, left retro-orbital cellulitis is better seen on the soft tissue neck examination. A small polyp vs mucus retention cyst is noted in the right maxillary sinus. Post-surgical changes related to left submandibular and masticator space abscess drainage persistent myositis related to the muscles of mastication and mild parotitis.

Case Discussion

Brain abscesses are a rare, but life-threatening complication of odontogenic infection. Existing literature suggests hematogenous spread as the primary pathway for infectious spread. However, in our case contiguous spread from periodontal disease or as an iatrogenic dental complication is the primary pathophysiological mechanism evidenced by the comprehensive multi-modal imaging performed after admission. We report the case of a 15 year old female presenting with fevers and facial swelling around left mandible. No evidence of intra-cranial or orbital spread was demonstrated on early imaging. Over the course of 13 days, combined clinical signs and radiological evidence, demonstrated the spread of infection from a left mandibular abscess to the left orbit and epidural space after which patient underwent craniotomy with incision and drainage of the orbital space and dental extraction.

In a meta-anlysis of 60 cases of odontogenic brain abscesses, Moazzam et al. find that while virtually all patients received antibiotics, 85% required neurosurgical intervention. While past studies looking at treatment between 1960-1980 find a mortality rate of 30%, Moazzam et al. finds an eight percent mortality rate and 28% of cases survived with neurologic sequelae. They also propose that molar teeth lesions have the highest risk of associated CNS infection. 

This case highlights the importance of monitoring oral infections for serious potential complications and the deceptively variable course of disease. Our patient initially appeared to improve from their dental abscess, but one week later the infection had spread to the orbits and brain. Early signs of spread through soft tissue could warn future physicians of the risk of spread of dental abscess to brain and encourage early aggressive intervention.

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