In this lecture, we're going to learn about cerebritis. Let's start with a case. A 56-year-old
man with headache. This is a 56-year-old man with diabetes mellitus who does not follow
with any physician and presents with new headache and aphasia, problems with getting the
words out. This began about 1 week ago and he has worsened steadily. He has had
intermittent fever, severe tooth pain, and there is concern for a periapical abscess in and
around the first right maxillary molar. Examination shows an expressive type aphasia, he
can't get his words out, with impaired fluency, intact comprehension to commands, and intact
repetition. There is frontal lobe dysfunction. The temporal lobe appears normal and this looks
like a transcortical motor dysfunction with intact repetition and naming. Otherwise, neurologic
exam is unremarkable. MRI shows an enhancing lesion in the left frontal lobe with surrounding
edema. So what's the diagnosis? Well let's walk through and dissect to this case. This patient
needs imaging. There is some process that's been going on that sounds like it's infection.
There is a periapical abscess, a potential nidus in the maxilla to infection in the brain.
Examination shows a focal examination, a focal neurologic deficit with this expressive type
aphasia, and that requires imaging. And the imaging shows an enhancing lesion in the left
frontal lobe which we'll take a look at in the next slide. So here is this patient's imaging.
We're looking at a T2 weighted image, a T1 weighted image with gadolinium contrast, and
then on the far right we see the diffusion weighted image. So what do you see? On the left,
I see a lesion in the brain with surrounding vasogenic edema. In the middle, we see the
periphery of this lesion is enhancing with contrast and we know that things that enhance with
contrast are acute, infections, inflammation, and malignancy. This patient's clinical presentation
is not consistent with malignancy which would be lower on our differential. Inflammation
or MS would be uncommon to present in this way. And infection is at the top of our differential.
The diffusion weighted image shows prominent diffusion restriction in the center of this lesion,
that necrotic core that you see on the gadolinium image and that suggest infection and points
us strongly towards an abscess. So what's the diagnosis? Well, this doesn't look like meningitis,
encephalitis, or cerebritis. The imaging is most consistent with brain abscess and this is a
typical presentation, a patient with mild low grade fevers, a new focal neurologic deficit, and a
potential nidus for seeding infection into the brain.