An expert’s guide to encephalitis
Encephalitis is a neurological disorder and specifically an inflammation of the brain. It's most commonly caused by viral infections, although autoimmune and bacterial causes also exist. The condition can affect anyone, and early recognition and treatment are crucial to prevent serious complications and support recovery.. Both can present with serious symptoms and require prompt assessment by a specialist to avoid long-term complications.
What causes encephalitis?
Viral infections are the most frequent cause of encephalitis. Common viruses include herpes simplex virus, varicella-zoster virus and, less frequently, measles or mumps. Autoimmune encephalitis occurs when the body’s immune system mistakenly attacks brain cells. Rarely, bacteria, fungi or parasites may also trigger the condition.
What are the symptoms of encephalitis?
Symptoms can develop suddenly or over several days and may include:
- Fever and flu-like symptoms
- Headache and confusion
- Seizures
- Changes in behaviour or personality
- Weakness or problems with coordination
- Sensory changes such as visual disturbances
In severe cases, patients may experience reduced consciousness or coma.
How is encephalitis diagnosed?
Diagnosis usually involves a combination of clinical assessment and investigations:
- Blood tests to detect infection or autoimmune activity
- Lumbar puncture to analyse cerebrospinal fluid for signs of infection or inflammation
- MRI scans to identify areas of brain inflammation
- Electroencephalogram (EEG) to detect abnormal brain activity
Early diagnosis helps guide targeted treatment and improves outcomes.
How is encephalitis treated?
Treatment depends on the underlying cause:
- Antiviral medications for viral encephalitis, particularly for herpes simplex virus
- Immunotherapy, such as corticosteroids or intravenous immunoglobulins, for autoimmune cases
- Supportive care including hydration, nutrition and management of complications such as seizures or increased intracranial pressure
Recovery can take weeks to months, and patients may require rehabilitation to regain cognitive and physical function.
What is the outlook for patients?
Most people recover fully from mild encephalitis, but severe cases can leave lasting neurological or cognitive difficulties. Early recognition and prompt treatment significantly improve prognosis, and ongoing follow-up with a neurologist helps monitor recovery and manage any long-term effects.