Pyogenic brain abscess due to Streptococcus anginosus

A 23-year-old previously healthy Filipina migrant woman presented with confusion and worsening headache.

Magnetic resonance imaging showed a 4.6 × 5.1 cm ring-enhancing lesion in the left thalamus, with extensive surrounding oedema (Figure, A and B).

Microscopy of a biopsy sample showed pus and gram-positive cocci. Cultures grew Streptococcus anginosus (also known as Streptococcus milleri), an organism that is part of normal oral flora and a well known cause of metastatic abscesses.

The patient admitted to undergoing multiple recent tooth extractions (Figure, C). She was treated with 6 weeks of intravenous benzylpenicillin and made a full recovery, with complete abscess resolution on follow-up imaging.