Expressive aphasia caused by Streptococcus intermedius brain abscess in an immunocompetent patient

Brain abscess is an uncommon but life-threatening infection. It involves a focal, intracerebral infection that begins in a localized area of cerebritis and develops into a collection of pus, surrounded by a well-vascularized capsule. Brain abscess still poses a significant problem in developing countries but rarely in developed countries. Predisposing factors vary in different parts of the world. With the introduction of antibiotics and imaging studies, the mortality rate has decreased between 5% and 15%. If left untreated it may lead to serious neurologic sequelae. The temporal lobe abscess can be caused by conditions like sinusitis, otitis media, dental infections, and mastoiditis if left untreated or partially treated. Additionally, in neurosurgical procedures like craniotomy, the external ventricular drain can get infected, leading to abscess formation.

We present the case study of an elderly female patient who presented with expressive aphasia caused by brain abscess, secondary to Streptococcus intermedius infection. The 72-year-old female with a medical history of hypertension came to hospital for evaluation with word-finding difficulty, an expressive aphasia that began a few days prior to presentation. Computed tomography of the head showed a left temporal lobe mass-like lesion, with surrounding vasogenic edema. The patient was empirically started on courses of antibiotics. The next day, she was subjected to magnetic resonance imaging of the brain, which showed a left temporal lobe septated rim-enhancing mass lesion, with bright restricted diffusion and diffuse surrounding vasogenic edema consistent with abscess. The patient was also seen by the neurosurgery department and underwent stereotactic, left temporal craniotomy, with drainage, and resection of abscess. Tissue culture grew S. intermedius sensitive to ampicillin sulbactam. Subsequently her expressive aphasia improved.

Brain abscess has a high mortality, however a significant proportion of patients with appropriately treated abscess recover completely and can survive without significant neurologic damage. Advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Biopsy of brain lesion with early initiation of appropriate antibiotics will change the outcome.