Correspondence

Herpes Simplex Encephalitis

N Engl J Med 1996; 335:209July 18, 1996

Article

To the Editor:

Drs. Watemberg and Morton (March 7 issue) describe a case of herpes simplex encephalitis in a 13-year-old boy and present the classic electroencephalographic finding of periodic lateralized epileptiform discharges.1 Whereas it is gratifying to learn that the boy recovered fully after treatment with 15 mg of acyclovir per kilogram of body weight per day for 14 days, the only studies that have prospectively evaluated intravenous acyclovir for the treatment of herpes simplex encephalitis have used a dosage of 30 mg per kilogram per day (10 mg per kilogram every 8 hours) for 10 days.2,3 This standard dose of acyclovir should be used for the treatment of herpes simplex encephalitis unless there is evidence from clinical trials that demonstrates the superiority of another dosing regimen.

Stephen D. Shafran, M.D.
University of Alberta, Edmonton, AB T6G 2B7, Canada

3 References

1. 1

   Watemberg N, Morton LD. Periodic lateralized epileptiform discharges. N Engl J Med 1996;334:634-634
   Full Text | Web of Science | Medline

2. 2

   Skoldenberg B, Forsgren M, Alestig K, et al. Acyclovir versus vidarabine in herpes simplex encephalitis: randomised multicentre study in consecutive Swedish patients. Lancet 1984;2:707-711
   CrossRef | Web of Science | Medline

3. 3

   Whitley RJ, Alford CA, Hirsch MS, et al. Vidarabine versus acyclovir therapy in herpes simplex encephalitis. N Engl J Med 1986;314:144-149
   Full Text | Web of Science | Medline

To the Editor:

The legend to the Image in Clinical Medicine on periodic lateralized epileptiform discharges refers several times to the wave forms shown in the image as having an activity of a certain number of “hz per second.” In the physical sciences, the unit of frequency is the hertz, abbreviated Hz. In primitive units, 1 Hz is equivalent to one cycle per second. The authors were pointing out the dominant frequencies of the wave forms, and the correct usage should have been either “Hz” or “cycles per second” but not “Hz per second.”

Nelson Thompson, B.S.
Department of Veterans Affairs, Houston, TX 77030