A Case of Streptococcus anginosus Brain Abscess Caused by Contiguous Spread from Sinusitis in an Immunocompetent Patient

Abstract

Brain abscesses are infections of the brain parenchyma that can arise from either contiguous spread from local infection or by hematogenous spread from a distant site. Streptococcus anginosus of the Streptococcus anginosus group (SAG) is a commensal microbe of the mucosae of the oral cavity, gastrointestinal tract, and urogenital tract. We present a case of mono-microbial brain abscess caused by contiguous spread from relatively asymptomatic sinusitis that initially presented as a subdural hemorrhage on computed tomography.A 70-year-old male presented, obtunded, with a Glasgow Coma Score of eight. The patient seized on arrival. A computed tomography scan was read as a subdural hemorrhage, and magnetic resonance imaging showed a heterogeneous area at the anterior tip of the left frontal lobe interpreted as a frontoparietal abscess, along with pansinusitis. Craniotomy revealed a loculated abscess. Culture grew only Streptococcus anginosus. The patient did well postoperatively, was extubated by day five with rapidly improving neurological function, and was discharged to inpatient rehab by hospital-day eight for the continuation of intravenous antibiotics.This case represents a frontal lobe abscess caused by the contiguous spread of Streptococcus anginosus from a frontal sinus infection. This is a relatively rare presentation of SAG infection in an immunocompetent patient. The case outlines the importance of imaging modality choice in the various stages of brain abscess formation, and the necessity of maintaining an index of suspicion for brain abscess in patients with few traditional risk factors and little to no history on presentation.

Intracranial infections: lessons learned from 52 surgically treated cases

“…4,20,25 Streptococcus anginosus is a commensal microbe of the mucosae of the oral cavity, gastrointestinal tract, and urogenital tract and is rarely found in brain abscess materials or immunocompetent patients. 12 We identified this etiological agent in an immunocompetent patient with a left frontal intracerebral abscess that was treated successfully with craniotomy and drainage. In our series, a microbial agent was not identified in most cases.…”

“…6,25 The microbiological etiology of the abscess depends on many factors such as the site of primary infection, a patient's age and immunological condition, underlying diseases, and the geographic location of the patient. 12 Subdural empyema is also a pyogenic infection but is located between the dura and arachnoid matres. It is an uncommon condition, representing 15%-20% of confined intracranial diseases.…”

Streptococcus anginosus bacteremia: a septic IVC thrombus and a large empyema requiring decortication

“…This gram-positive, catalase negative organism is notorious in causing invasive bacterial infections such as multiple abscesses with involvement of numerous organs. 1 This usually occurs by means of hematogenous spread/bacteremia, but another mechanism includes direct spread from a nearby source, such as brain abscesses developing in patients with mastoiditis or sinusitis. 1,2 These abscesses frequently occur in the liver, brain and lungs.…”

Characterization and spontaneous induction of urinary tract Streptococcus anginosus prophages

“…S. anginosus is now considered an emerging pathogen. It has been associated with infections of the respiratory tract [4][5][6], brain abscesses [7,8], liver abscesses [9], and skin and soft tissue infections [10]. It also has been isolated from infections of the head and neck, central nervous system, gastrointestinal tract and blood [6,9].…”