A 31-year-old man found unresponsive.
A
B
C
What is your diagnosis?
The answer is Herpes Simplex Encephalitis
Herpes simplex virus (HSV) encephalitis is generally thought to occur as a form of reactivation of HSV-1 virus in the ganglion of the trigeminal nerve, which subsequently travels along a nerve axon to the brain.
T2-weighted FLAIR MRI (figures A and B) reveals hyperintensity corresponding to edematous changes in the temporal lobes, inferior frontal lobes, and insula, with a predilection for the medial temporal lobes.
The T2 hyperintensity reflects cytotoxic edema as shown with restricted diffusion on DWI (figure C).
Typically, the basal ganglia are spared.
中文版：
男性，31歲，發現無反應
診斷：單純皰疹病毒性腦炎
單純皰疹病毒性腦炎通常認為是因三叉神經節處的單純皰疹病毒1型重新活化，並通過神經軸索播散至腦內而引起。
病變於MRI T2FLAIR像（A,B圖）表現為顳葉、額葉底部以及島葉異常高信號，尤其好發於顳葉內側，提示為水腫改變。
T2WI表現為高信號，DWI表現為彌散受限，表明病變區域為細胞毒性水腫（C圖）。
雙側基底節區通常不受累及。