Teaching Point or Hint:
This T2 MRI shows multiple areas of abnormal gray matter hyperintensity (white).
Red - temporal lobe and orange - cingulate gyrus
TITLE: Herpes Simplex Encephalitis (HSV1) Typical Case
Companion Case - Herpes simplex encephalitis usually affects the cortical gray matter, especially early in the disease. Temporal lobe and insular cortex are usually first (red outlines)- with abnormal signal intensity (bright on FLAIR and T2W), cortical thickening (sulcal effacement), and variable enhancement. Similar changes occur in the cingulate gyrus (orange outlines) in up to 2/3 of patients.The inferior frontal gyri may be affected next. Since vascular/ischemic lesions also affect the cortex, a non-vascular pattern of involvement (e.g. bilateral insula or insula plus cingulate) can be very helpful. Involvement of the basal ganglia gray matter is uncommon and/or late in the course of HSV encephalitis.