(See also Meningitis)
What is encephalitis?
Encephalitis is an inflammation of the brain. It is caused either by an infection invading the brain (infectious encephalitis) or through the immune system attacking the brain in error (post-infectious or autoimmune encephalitis). Although rare, it is potentially life-threatening and may lead to permanent brain damage or death.
Viruses are the most frequently identified cause of infectious encephalitis, including the herpes simplex virus (HSV – which also causes cold sores) and enteroviruses. In some cases, infections are caused by mosquito bites (e.g. Murray Valley encephalitis, also known as Australian encephalitis, or equine encephalitis). A milder form can also accompany some common childhood diseases such as chickenpox, measles, mumps, and rubella (German measles).
Symptoms
Encephalitis may cause different symptoms depending on the type. The most common symptoms may include a high fever and headache, accompanied by a stiff neck, vomiting, light sensitivity, and seizures. Patients may also be drowsy or confused, and difficult to rouse. In babies, there may be a bulge in the fontanelle. Many of these symptoms also occur in other illnesses (e.g. migraines), so the presence of fever is an important indication.
Treatment
Most patients are admitted to hospital, and treatment will depend on the diagnosis of the cause. Anti-viral or anti-bacterial medicines may be prescribed, along with other medications to relieve the symptoms, such as corticosteroids to reduce inflammation, anti-convulsants, and medications for pain relief.
Outlook
The prognosis for a person with encephalitis varies according to the age of the patient – with the very young and very old particularly at risk – and the particular virus that caused the disease. While many people make a full recovery, in severe cases, the illness may be fatal or result in brain damage. Recovery from encephalitis may require multidisciplinary care from speech therapists, physiotherapists, and occupational therapists to manage ongoing symptoms like memory loss, seizures, and balance or speech difficulties.
Further Information and Support
- Encephalitis International: www.encephalitis.info
- Australian Autoimmune Encephalitis Consortium: https://www.monash.edu/medicine/autoimmune-encephalitis
- Healthdirect: https://www.healthdirect.gov.au/encephalitis
Reviewed by: Dr Matthew Kiernan, PhD, FRACP, Consultant Neurologist, Prince of Wales Hospital
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