Neurological complications of varicella-zoster virus infection in children

Varicella-zoster virus is an exclusively human α-herpesvirus, known as the aetiological factor of chickenpox which is usually linked with childhood. The disease occurs with a worldwide geographic distribution, and in temperate climates shows a seasonal pattern with epidemics occurring mostly during late winter and spring. The annual incidence is estimated at 80–90 million cases worldwide. Children usually acquire varicella during the first five to 10 years of life, and the highest risk of infection is related to household contacts without a history of vaccination. Although the disease is commonly considered benign, varicella-zoster virus bears the potential of causing a wide range of complications, including the most serious ones of central nervous system manifestations. The neuropathogenesis of varicella-zoster virus infections is not well understood. Based on a wide spectrum of clinical syndromes, multiple theories explaining the pathways of spread of the virus, and host immune response to the viral presence have been proposed, including direct retrograde trafficking of the virus and haematogenous spread as well as inflammatory response with vasculitis. Neurological complications related to varicella-zoster virus infection are the second most common indication for hospitalisation in immunocompetent children with varicella, following skin superinfections. In this paper, the neurological aspects of chickenpox in children are discussed. The characteristics of the clinical syndromes, pathogenesis, methods of diagnosis and treatment, as well as long-term consequences are presented.