Streptococcus Intermedius Brain and Diverticular Abscesses After Dental Manipulation: A Case Report

Abstract

A brain abscess is defined as a focal intracerebral infection consisting of an encapsulated collection of pus, which can be a life-threatening complication of infections, trauma, or surgery. While immunocompromised patients can have a wide array of causative organisms, bacterial species represent the most common etiology in immunocompetent individuals. The incidence of brain abscesses ranges from 0.4 to 0.9 per 100,000, with a high predisposition among immunocompromised patients and in those with disruption of the blood-brain barrier. The most common causative organisms found were Streptococcus species, particularly S. viridians and S. pneumonia, Enterococcus, and Staphylococcus species, mainly S. aurieus and S. epidermidis. Microorganism can invade the brain through different mechanisms, either directly by contiguous spread and odontogenic infections, which usually cause a single brain abscess, or indirectly through hematogenous spread which can cause multiple brain abscesses. Both surgical and conservative dental procedures contribute to hematogenous spreading of oral microorganisms. Although most of those organisms are eliminated shortly after they gain access to the bloodstream, some can persist and contribute to the pathogenesis of abscesses in the appropriate environment. Odontogenic origins are rarely implicated in the formation of brain abscesses, and oral foci comprise approximately 5% of identified cases. We report a case of brain and diverticular abscesses due to S. intermidius occurring two months after dental extraction. This case highlights the fact that even usual dental workup can result in the development of bacteremia and disseminated abscesses including but not restricted to the brain. Consequently, in addition to identifying the possible source of bacteremia with an extensive history and physical exam, the diagnosis of Streptococcus milleri organisms should prompt the physicians to screen for sites of possible metastatic infection spread.

Keywords: brain abscess; diverticular abscess; streptococcus intermedius.

Figure 1. Imaging Findings

A 4.6 cm abscess with rim-enhancing lesion in the right cerebellar hemisphere (red arrows) and extensive surrounding edema (yellow arrows) seen on (A) T1 post contrast and (B) diffusion weighted imaging (DWI).

Figure 2. Diverticular Abscess on Computed Tomography (CT) Imaging

CT scan showing sigmoid diverticulitis with surrounding inflammation and an adjacent lobulated 6.9 x 5.4 x 6.1 cm abscess (yellow arrow) on (A) coronal and (B) axial sections.