Central nervous system herpesvirus infections

Abstract

The herpesviridae family are important causes of central nervous system disease in children. We review the spectrum of disease caused by the viruses in the context of a brief description of their epidemiology and transmission. Herpesviridae establish lifelong latency following primary infection and we clearly categorise those diseases associated with primary infection and those associated with reactivation with a particular emphasis on the immunocompromised child. Although a causal association with neurological disease in children is established for HSV and VZV syndromes, we identify the ongoing challenge of establishing causation for other viruses because of the rarity of presentations and viral latency. We review the diagnosis, management and outcome issues with recognition that more research is required.

Introduction

The herpesviridae family of DNA viruses includes eight distinct viruses within 3 sub-families (Table 1). Herpesviridae are characterised by high rates of primary infection – often asymptomatic or produce only mild symptoms – with the potential for severe disease. These viruses establish long-term latency in humans, characterised by persistence of viral genome with limited gene expression, but can periodically reactivate to produce infectious virus in response to a variety of triggers including immunosuppression, causing subclinical virus shedding or recurrent disease. Except for human herpesvirus 8 (HHV-8 or Kaposi's sarcoma-associated herpesvirus) all the herpesviruses cause or have been associated with central nervous system (CNS) disease in children, with a wide variety of clinical syndromes (Table 1).