Curriculum · Neurology
Herpes simplex encephalitis
What it is
Herpes simplex is a common viral infection. HSV type 1 favors the mouth and the nose and gives lip and skin lesions, while HSV type 2 favors the genitalia, the buttocks and the thighs; the simple way to hold this is that upper is 1 and low is 2. Herpes encephalitis is described with both HSV-1 and HSV-2. In an immunocompromised patient the infection can move on to encephalitis.
How it presents
On the skin the infection presents as painful, grouped vesicles on an erythematous base, and in a child the picture is gingivostomatitis, with vesicles that ulcerate. Herpes labialis gives cold sores and fever blisters.
Herpes encephalitis is not held to one age group; it is described in the young patient and in the old one. The signs that point to it are:
- New onset seizure.
- Change in personality, or hallucinations.
Hemorrhage of the temporal lobe belongs to the same picture.
How it is diagnosed
The CSF in viral infection is lymphocyte predominant. The test given for herpes encephalitis is HSV PCR on the CSF. For the skin and the lip lesions the tests are Tzank smear, PCR and direct fluorescent antibody, and in the child the diagnosis of gingivostomatitis is made on the picture itself.