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.
Highlights
Streptococcus intermedius (S. intermedius) is a gram-positive oral bacterium that is part of the Streptococcus milleri group
It is a known inhabitant of the oral cavity as well as the upperrespiratory, gastrointestinal, and female urogenital tracts [1]. This organism is considered part of the normal flora, it can present as an opportunistic pathogen. It is a common cause of brain abscesses, liver abscesses, and other serious purulent infections
Malignancy, and diabetes are widely known to increase the risk of infection with Streptococcus intermedius [2]
Summary
Streptococcus intermedius (S. intermedius) is a gram-positive oral bacterium that is part of the Streptococcus milleri group. Cases of S. intermedius brain abscesses reported previously were associated with an active oral infection. A 56-year-old woman with a history of ductal carcinoma in-situ status post lumpectomy and radiation therapy in 2006, hypothyroidism, and diverticulosis, presented for dizziness and headaches for two days. Her headaches had been intermittently present for a few weeks but were progressively worsening, up until the week of admission when she began having blurry vision, dizziness, and what she reported as the worst headache of her life. Magnetic resonance imaging (MRI) of the brain one day after presentation showed a 4.6 cm rim-enhancing lesion with extensive surrounding edema. 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
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