Neuropediatrics 2004; 35(6): 371-376
DOI: 10.1055/s-2004-830372
Short Communication

Georg Thieme Verlag KG Stuttgart · New York

Relapse of Herpes Encephalitis after Acyclovir Therapy: Report of Two New Cases and Review of the Literature

I. Valencia1 , D. K. Miles1 , J. Melvin1 , D. Khurana1 , S. Kothare1 , H. Hardison1 , A. Legido1
  • 1Section of Neurology, Department of Pediatrics, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA, USA
Further Information

Publication History

Received: September 15, 2003

Accepted after Revision: September 16, 2004

Publication Date:
15 November 2004 (online)


Relapse of herpes simplex virus (HSV) encephalitis following acyclovir therapy has been reported infrequently in children beyond the neonatal period. The pathogenic mechanism of the recurrence is not fully understood. We report two new cases that support a mechanism of latent HSV infection with reactivation of the disease. Our patients were 2 years (#1) and 8 months (#2) old at initial infection. Both presented with fever, lethargy, focal seizures, and focal motor abnormalities. Serum HSV antibodies (Abs) were negative. The patients were treated with acyclovir for 14 and 21 days, respectively. They were readmitted at 1 month, and 4 days after discharge, respectively, with recurrent lethargy, seizures, and choreo-athetoid movements. Serum and CSF HSV Abs were significantly increased. CSF PCR was positive. In patient # 2 acyclovir-sensitive HSV was isolated from a brain biopsy. Both patients were re-treated with acyclovir, but progressed to a neurovegetative state. In our cases, latent HSV infection and reactivation is the most likely explanation for recurrent encephalitis. The immuno-pathogenic mechanisms of the infection recurrence are discussed. Based on the reported cases in the literature, patients younger than 2 years of age and with lower total dose of acyclovir treatments have a higher risk of recurrence.


M.D. Ignacio Valencia

Department of Pediatrics
Section of Neurology
St. Christopher's Hospital for Children

Erie Avenue at Front Street

Philadelphia, PA 19134