The incidence of cerebral abscesses ranges from 0.4 – 0.9 cases per 100 000 people and is more frequent in immunocompromised patients. They account for 1 per 10000 hospital admissions.
Dental infections have occasionally been reported as the source of the microorganisms which can give rise to a brain abscess.
What are they?
A brain abscess is a rare but life-threatening infection in which a localised area of suppuration develops within the brain parenchyma.
The most common sites are the temporal lobes (42%), followed by the cerebellum (30%).
They may occur following:
- cranial trauma
- cranial surgery
- 2nd to a septic focus elsewhere, spread either by direct extension / haematological route.
Brain abscesses occur more frequently in men than in women. Odontogenic brain abscesses in children are virtually unheard of.
In view of the relative rarity of brain abscess, there may be delays in making the diagnosis, so this condition remains a significant challenge for clinicians.
Dental procedures alleged to have caused a brain abscess are very wide ranging. These include:
- Dental extraction
- operative dentistry
- periodontal therapy
- dental local anaesthetic injection
- dental prophylaxis
The range of procedures that can seemingly elicit brain abscesses suggest that the mechanism responsible to produce the bacteræmia that causes the brain abscess is not as critical as the host response.
Within 1 minute of a dental procedure, micro-organisms from the mouth may have reached the heart, lungs and peripheral capillary system. In most individuals, the reticulo-endothelial system eliminates these microbes in a matter of minutes.
This is not the case in immune-compromised populations, for example, organ transplant patients and those with AIDS where there has been a reported increased incidence of brain abscess.
Although certain underlying brain pathologies such as a previous stroke or underlying cancer may serve as a focus for abscess formation, in most cases there is no apparent predisposing brain lesion.
Brain abscess linked to a dental source is a rare occurrence, as in most individuals, the blood-brain barrier along with the immune response will stop the entry of microorganisms into the brain. Direct spread tends to cause solitary abscesses whereas as hæmatogenous spread usually results in multiple abscesses. Anærobic species are responsible for the majority of the cases of odontogenic brain abscesses (78%).
Often the diagnosis has been one of exclusion as opposed to evidence.
One of the major criticisms linking possible odontogenic (dental) infections with brain abscess is identification of the causal organisms in both sites. Since brain abscesses often occur spontaneously, the source of infection is searched for retrospectively. Dental sources of infections, especially periodontal diseases are commonly found in the adult population. Thus, the link may be causal or hypothetical.
Mortality ranges from 0 – 24% for odontogenic brain abscesses.
Useful Articles & Websites
Endod Dent Traumatol 1999. Brain Abscesses caused by Oral Infection
Postgrad Med J 1999. Refractory Thrombocytopenia, Recurrent Abortions & Inferior Vena Cava Thrombosis
Oral Dis 2001. Are Dental Infections a Cause of Brain Abscess. Case Report & Review of the Literature
Ann R Coll Surg Eng 2012. A Case of Odontogenic Brain Abscess arising from Covert Dental Sepsis
JADA 2014. Multiple Brain Abscesses in an Immunocompetent Patient after Undergoing Professional Tooth Cleaning
BMJ Case Rep 2015. Case Report. Fatal Thalamic Abscess secondary to Dental Infection
BMJ Case Rep 2017. Case of a Cerebral Abscess caused by Porphyromonas gingivalis in a subject with periodontitis
Romanian Neurosurgery 2018. Brain Abscess + Dental Infections – A Review
BMC Oral Health 2019. Cerebral Abscess following the Self-Extraction of Teeth in Patient with Ebstein’s Anomaly. A Case Report
Can J Ophthalmol 2019. Occipital lobe abscess following wisdom tooth extraction
J Oral Med Oral Surg 2019. Short Case Report. From dental infection to Extradural Empyema – A Case Report
Maxillofacial Plastic & Reconstructive Surgery 2019. Multiple Brain Abscesses Treated by Extraction of the Maxillary Molars with Chronic Apical Lesion to Remove the Source of Infectiont
Case Reports in Emergency Medicine 2020. Brain Abscess Secondary to a Dental Infection
Int J Surg Case Reports 2020. Case Series. Brain abscesses and intracranial empyema due to dental pathogens.
J Infection 2020. Microbial aetiology of brain abscess in a UK cohort. Prominent role of Streptococcus intermedius
Arq Bras Neurocir 2021. Multiple Brain Abscesses Secondary to Odontogenic Infection – A Clinical Case Report
J Med Healthcare 2021. Brain Abscess of Dental Origin – A Case Report & Literature Review