Link Between Dental and Brain Abscesses?

I found the article¹ about the case of a brain abscess interesting, but the conclusion linking it to a dental cavity is irritatingly vague, unscientific and bordering on sensational journalism.

Streptococcus anginosus is an opportunistic, normal part of the flora found in the oral cavity, throat and gastrointestinal tract that is commonly isolated from abscesses in the bodies of people that are immunocompromised. There was no evidence to link it to that decayed tooth: no swelling, purulence or other signs of infection.  If the authors can leap to that conclusion, then one would suspect that—with the millions of children with real dental and throat infections every day—brain abscesses would rampant.

Really the point is irrelevant because ultimately brain abscesses are a rare neurologic problem, not even in the consideration of dentists.

Response from the Authors

Thank you for your comments on our article.¹ Certain words in your letter (e.g., decayed tooth, real dental infections) imply that tooth 75 was not abscessed but merely carious. However, the primary molar in this case report was grossly carious, had a furcation radiolucency and a recent history of pain and localized swelling. These signs and symptoms were adequate to lead to a working diagnosis of dental abscess of tooth 75. Post-extraction culture of samples from the extraction socket confirmed the diagnosis of an abscessed tooth.

We agree that Streptococcus anginosus is regularly cultured in the oral cavity, genitourinary tract and gastrointestinal tract as well as in immunocompromised individuals with purulent infections of the liver, central nervous system and lungs. However, it has been repeatedly cultured and involved in the formation of odontogenic abscesses in immunocompetent individuals.^2,3 Furthermore, the literature indicates that intracerebral abscesses are more common in immunocompetent children and adolescents than those who are immunocompromised.⁴

In response to your statement that “there was no evidence to link it (brain abscess) to that decayed tooth...”, we took great care to identify this case as a diagnosis of exclusion. Medical investigations revealed no other predisposing risk factors aside from the odontogenic abscess secondary to necrotic tooth 75. Patients with life-threatening infection often receive antibacterial therapy prior to specimen collection that can compromise bacterial culture results. Twenty-four to 40% of all intracerebral abscesses produce negative culture results in large part due to prior antimicrobial therapy.⁵ In this report, streptococcus species were cultured from the tooth 75 extraction socket and Streptococcus anginosus was cultured from the brain abscess.

As for the evidence to support the link between the brain abscess and the abscessed tooth 75, we believe this case report is an accurate description of an unusual occurrence. It was never meant to suggest that any patient with a throat, ear or dental infection is at immediate risk of a brain abscess. Brain abscesses are rare as the body has multiple defense systems to prevent contiguous and systemic spread of infections to the brain. Based on biological principles, the spread of a dental, ear or throat infection to the brain does occur and the literature contains numerous examples.^4,6

All health care personnel need to be aware of the potential consequences of an untreated odontogenic infection. Brain abscess in children is a rare but serious condition as it can lead to permanent neurologic sequelae or death. Although many children live with localized dental abscesses, in this rare case, the abscess was the prime causal candidate for the brain abscess.

Cite response as: J Can Dent Assoc 2012;78:c118