A new study shows that bacteria known to cause infections in the mouth may also be a contributing factor in patients developing life-threatening brain cysts.
The study, published in the journal Dentistry, looked at brain cysts and their association with bacteria that occur in the oral cavity.
While this type of cyst is relatively uncommon, it can lead to mortality or significant morbidity.
The researchers examined the records of 87 patients hospitalized with brain abscesses, and used microbiological data obtained from abscess sampling and cultured samples in the laboratory.
This allowed them to investigate the presence of oral bacteria in abscesses in the patients’ brains, as the cause of the abscess was identified in only 35 patients, or it was never found.
Their results showed that the 52 patients whose cysts had no cause were three times more likely to have oral bacteria in their samples, compared to patients for whom the cause of their cysts was known.
These patients also carry significantly higher numbers of Streptococcus anginosus, a bacterium that can lead to pharyngitis, bacteremia and inflammation of internal organs such as the brain, lung and liver. These bacteria are often found in dental abscesses.
A brain abscess is a swelling of the brain filled with pus, and it usually occurs when bacteria or fungi enter the brain tissue after an infection or after a severe head injury.
In a university statement, the study’s lead author, Dr Holly Roy, said the findings underscore the importance of good oral hygiene.
She explained, “While many possible causes of brain abscesses are being identified, the clinical origin of the infection often remains unknown. However, it was surprising to find oral bacteria occurring frequently in brain abscesses of unexplained origin.” .
“This highlights the importance of using more sensitive techniques to assess the oral cavity as a potential bacterial source in brain abscess patients. It also highlights the importance of improving dental care and overall oral hygiene.”
The study concluded, “These results indicate that the oral cavity may be considered as a source of hidden infection in cases of brain abscess for which no clear cause has been identified.”
Future studies should include oral screening and microbiome analysis in order to better understand the specific mechanisms and develop approaches for prevention.
The study forms part of ongoing research within the university’s Oral Microbiome Research Group, led by Dr Raul Pescus and Dr Zoe Brooks, to explore links between the oral microbiome and a range of cardiovascular and nervous system diseases.
Other clinical trials are underway to investigate links between gum health and Alzheimer’s disease and to identify patients at risk of cardiovascular disease in primary care dental clinics, as altering the balance of oral bacteria (the microbiome) during periodontal disease can lead to high blood pressure and strokes.
Symptoms of a brain abscess include:
Headache – which is often severe, located in one part of the head and cannot be relieved with painkillers
Changes in mental status – such as confusion
Problems with nerve function – such as muscle weakness, slurred speech or paralysis on one side of the body
– High temperature.
Vision changes – such as blurred, graying or double vision.