Dental extraction-associated cerebral abscess caused by Parvimonas micra

Abstract

Background:

Dental extraction-associated cerebral abscesses are rare. To date, Parvimonas micra has not been reported as the causative organism of such abscesses.

Case Description:

A 66-year-old male presented with generalized seizures 12 days after molar extraction. He had been diagnosed with periodontitis 4 years earlier. Following the extraction, he was prophylactically administered clarithromycin for 1 week. At presentation, he exhibited left hemiparesis and dysarthria, with a body temperature of 38.0℃. Blood tests revealed mild elevations in white blood cell count and serum C-reactive protein levels. Echocardiography revealed no abnormalities. Cerebral magnetic resonance imaging demonstrated a cystic mass in the right frontal lobe, accompanied by rim-like enhancement and extensive perilesional edema, as well as hyperintensity on a diffusion-weighted sequence. The patient underwent burr-hole drainage, which yielded purulent discharge. Culture of the pus isolated P. micra and Fusobacterium nucleatum.

Conclusion:

Cerebral abscesses may develop following dental extraction, and careful observation is required afterward. Early onset of neurological symptoms after dental extraction should raise suspicion of a cerebral abscess requiring timely surgical intervention.

INTRODUCTION

Cerebral abscess is a neurosurgical emergency. Optimal management involves surgical drainage for lesions ≥2.5 cm, management of the primary source, treatment of concurrent hydrocephalus, and prolonged administration of sensitive intravenous antibiotics.[12] Dental extraction-associated cerebral abscesses are rare, with only seven cases reported to date.[1,4,5,8-10,14] Parvimonas micra is a common oral bacterium that rarely causes odontogenic cerebral abscesses.[3,13] However, to the best of our knowledge, there have been no reports of dental extraction-associated cerebral abscesses caused by P. micra.

Herein, we report a case of cerebral abscess caused by P. micra and Fusobacterium nucleatum that developed 12 days after dental extraction, with a brief review of the literature.

CASE PRESENTATION

A 66-year-old male with a history of periodontitis presented with generalized seizures. He had undergone the extraction of 2 molars located in the right upper dental arch, at a local dental clinic, 12 days before presentation. Following the extraction, he was prophylactically administered oral clarithromycin (400 mg/day) for 1 week. At presentation, the patient was well-oriented, but showed an elevated body temperature of 38.0℃, left hemiparesis graded 4/5 on manual muscle testing, and dysarthria. Oral examination found extraction sites in the right upper dental arch without redness, swelling, or discharge [Figure 1]. Seizure or signs of raised intracranial pressure were not found. Blood tests showed mild elevations in white blood cell count (10000/μL) and serum C-reactive protein (0.5 mg/dL). Echocardiography revealed no abnormal findings or valvular vegetations. Cerebral magnetic resonance imaging (MRI) revealed a cystic mass in the right frontal lobe, 30 mm × 35 mm × 34 mm in diameter, accompanied by rim-like enhancement and extensive perilesional edema. On diffusion-weighted sequences, the cyst contents appeared heterogeneously hyperintense [Figure 2]. With a presumptive diagnosis of cerebral abscess, the patient underwent burr-hole drainage, which yielded a dense purulent discharge [Figure 3]. Culture of the pus isolated P. micra and F. nucleatum, with the former predominating. Mycological analysis of it did not identify any causative organisms. Furthermore, the blood culture did not find a causative microorganism. He subsequently received intravenous antibiotics, ceftriaxone (2.0 g/day) and clindamycin (1.2 g/day), for 6 weeks, which resulted in the resolution of neurological impairments. The patient underwent assessment of higher cortical functions at the completion of antibiotic therapy that showed normal findings. MRI performed at the time showed remarkable regression of the cerebral abscess [Figure 4]. The patient has been followed for 6 months without recurrence or neurological deterioration.

Figure 1:

Photograph of the patient’s oral cavity showing traces of teeth extractions in the right upper dental arch, lacking findings of redness, swelling, or discharge (arrow).

Figure 2:

(a-c) Preoperative magnetic resonance imaging performed at the same level. (a) Axial diffusion-weighted sequence showing a heterogeneously hyperintense mass in the right frontal lobe (arrow). (b and c) Postcontrast (b) axial and (c) coronal T1-weighted magnetic resonance imaging showing a cystic mass in the right frontal lobe, 30 mm × 35 mm × 34 mm in diameter, with rim-like enhancement and perilesional edema (arrow).

Figure 3:

Photograph of dense purulent material intraoperatively collected in a test tube.

Figure 4:

(a) Axial and (b) coronal postcontrast T1-weighted magnetic resonance imaging performed at the completion of intravenous antibiotic therapy showing a remarkable regression of cerebral abscess (arrow).

DISCUSSION

Dental extraction, scaling, root planing, and other oral health procedures are associated with a high frequency of bacteremia.[11] In contrast, cerebral abscesses following dental extraction have been rarely reported.[1,4,5,8-10,14] Including the present case, eight patients have been described so far. They comprise four men and four women with a mean age of 38.5 years (range, 6–67 years). The interval between dental extraction and abscess onset ranged from 3 to 14 days (mean, 8.9 days). The causative organisms were commonly oral-resident bacteria. However, P. micra was identified only in our case. In two cases, dual organisms were identified. Prophylactic antibiotics were administered to only two of the eight patients [Table 1]. Of these, seven had no underlying condition predisposing to bacterial infection, while one had cyanotic congenital heart disease.[9]

Table 1:

Summary of published cases of dental extraction-associated cerebral abscesses.

The role of antibiotic prophylaxis in dental extractions remains uncertain. Grinkevičius suggested that routine use of prophylactic antibiotics was not supported in healthy patients, although amoxicillin/clavulanate might be an excellent option for preventing bacteremia in patients at risk.[6,7] In our patient with chronic periodontitis, despite prophylactic administration of clarithromycin, an odontogenic cerebral abscess developed. Clarithromycin, a macrolide antibacterial agent, reaches higher concentrations in the gingiva tissue than in serum and achieves higher levels in inflamed gingiva than in healthy gingiva. In general, clarithromycin is effective against oral resident bacteria, including P. micra and F. nucleatum.[2]

Although cerebral abscesses caused by P. micra are rare, the organism should be considered a possible pathogen in odontogenic abscesses, particularly in patients with a history of periodontitis.[3,13] For patients with dental extraction-associated cerebral abscesses, thorough history-taking, timely diagnosis, and prompt surgical intervention can lead to favorable outcomes.

CONCLUSION

Cerebral abscesses may develop following dental extraction, and careful observation is required regardless of prophylactic antibiotic administration. Early onset of neurological symptoms after dental extraction should raise suspicion of a cerebral abscess requiring timely surgical intervention.

Ethical approval:

The Institutional Review Board approval is not required.

Declaration of patient consent:

The authors certify that informed consent was obtained from the patient for the publication of this case report.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.

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