New guidelines for the investigation and management of encephalitis have been developed and released by the Australasian Society for Infectious Diseases (ASID) to help clinicians with one of the most complex challenges of the emergency department, according to a Clinical Focus article published in the Medical Journal of Australia.

The authors, led by Dr Philip Britton, Dean's Fellow at the University of Sydney, wrote that encephalitis "is caused by inflammation of the brain and is a challenging condition for clinicians to identify and manage".

"It manifests as a complex neurological syndrome ... that may be caused by a large number of aetiologies, many without effective treatments. It can be fatal and survivors often experience significant neurological morbidity", they wrote.

Although there are other guidelines for the investigation of encephalitis, they lack a specific geographic focus. "There are unique infectious aetiologies in Australia - including Hendra virus, Australian bat lyssavirus, Murray Valley encephalitis virus and West Nile virus (Kunjin virus) infections - that require early identification, reporting and specialist clinical and public health responses", the authors wrote.

"Regionally, causes of encephalitis with potential for introduction into and epidemic activity in Australia include Japanese encephalitis virus, enterovirus 71, dengue virus and Nipah virus."

The new guidelines were developed by ASID, with input from the Public Health Association of Australia, the Australian and New Zealand Association of Neurologists and the Australasian College for Emergency Medicine. The guidelines address two scenarios - the patient with possible meningoencephalitis, frequently encountered in emergency departments; and the patient in whom encephalitis is considered likely.

"Furthermore, it provides advice on the tests that should be done to diagnose the most common causes of encephalitis and defines specific patient subpopulations to highlight differences in aetiology (to help prioritise testing)", the authors wrote.

"These subpopulations include: children and neonates, immunocompromised patients, overseas travellers and immigrants, and patients residing in tropical Australia.

"Encephalitis presents a complex challenge to clinicians.

"Its possibility must be suspected in a variety of presentations, and it requires the performance of a detailed clinical assessment, consultation, and judicious investigation.

"Unnecessary delays must be avoided, and it is essential to institute empiric therapies appropriately and provide high-quality supportive management."