CASE HISTORY 3

A 35 year old white female presented to the Emergency Room in January with fever and a left focal seizure. She had been previously healthy, but developed fever and malaise one day before the seizure episode. In the Emergency Room, she was disoriented with a temperature of 39^o C. Physical examination was otherwise unremarkable. A CT scan of the head showed a focal area of low attenuation in the right temporal region, but without brain shift, LP revealed 100 WBC with 100% lymphocytes, 100 RBC, protein 100, glucose 60 (protein 8, glucose normal) CSF gram stain and culture were negative. Acyclovir was initiated for presumed herpes encephalitis. CSF was sent for PCR for HSV1 and HSV2 and was positive for HSV1. Viral culture of CSF was negative.

1. Should the patient be isolated? 

2. Was this likely an acute or recurrent infection? Does HSV-2 cause encephalitis? 

3. What clinical findings suggest herpes encephalitis as the diagnosis?

4. Why was PCR used to detect this viral infection instead of serology or virus isolation? 

5. What is the mechanism of action of acyclovir?