Viral encephalitis - update on pathogenesis and treatment.

Purpose of review: Viral encephalitis is a potentially devastating condition of cerebral inflammation manifest as a combination of fever, altered mentation, and sometimes focal neurological signs and seizures. In this review we explore the new developments in understanding of the epidemiology, pathogenesis and treatment options.

Recent findings: The WHO technical brief is a landmark document which sets the stage for the advancement of the surveillance, prevention and management of viral encephalitis. Adjunctive dexamethasone given in herpes simplex virus encephalitis is not associated with a worse outcome or CSF viral persistence but may not significantly improve overall outcome. Simple interventions in resource limited settings can significantly increase the proportion of patients with a syndrome or aetiological diagnosis of viral encephalitis.

Summary of implications: This review highlights ongoing research further elucidating the underlying pathophysiological mechanisms of brain injury, paving the way for adjunctive targeted immunotherapy which can ameliorate those aspects of the inflammatory response contributing to brain injury. Nevertheless, large-scale networks are required to establish the prospective, adaptive platform trials necessary. Pending this, as laid out in the WHO Technical Brief on encephalitis, preventive measures have the potential to save lives, including surveillance, vector control, and uptake of established and emerging vaccines.