HSV-1 encephalitis

Q: All of the following are the features of Herpes simplex virus (HSV) type 1 encephalitis except?

A) Klüver-Bucy syndrome (KBS)
B) lymphocytic pleocytosis in CSF
C) increased erythrocytes in CSF
D) elevated protein in CSF
 E) low glucose in CSF


Answer: E

HSV-1 encephalitis is the most common cause of sporadic fatal encephalitis in USA and around the world. It is characterized by its unique clinical symptoms and cerebro-spinal fluid (CSF) finding. 

Due to its affinity for the temporal lobe and limbic structures, neurological symptoms include elevated mood, excessive animation, decreased need for sleep, inflated self-esteem, and hypersexuality. 

KBS is consistent with "psychic blindness" (when a patient’s eyes are working, but the mind is not seeing), amnesia and loss of normal anger and fear responses. 

In CSF, all of the findings described i.e., lymphocytic pleocytosis, increased erythrocytes with atraumatic tap and elevated protein occurs, but low glucose should caution clinician to look for alternate diagnosis as it is almost not a case in HSV-1 encephelitis.


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References:

1.  Hart RP, Kwentus JA, Frazier RB, Hormel TL. Natural history of Klüver-Bucy syndrome after treated herpes encephalitis. South Med J 1986; 79:1376. 

2. Fisher CM. Hypomanic symptoms caused by herpes simplex encephalitis. Neurology 1996; 47:1374. 

3. Nahmias AJ, Whitley RJ, Visintine AN, et al. Herpes simplex virus encephalitis: laboratory evaluations and their diagnostic significance. J Infect Dis 1982; 145:829.