- This page has been taken from Encephalitis – a guide, which is available from our
Online Shop
Dr Nicholas Davies, Locum Consultant Neurologist, Imperial College Healthcare NHS
Trust
Encephalitis is inflammation of the brain. The inflammation is caused either by
an infection invading the brain (infectious); or through the immune system attacking
the brain in error (post-infectious / autoimmune encephalitis).
Encephalitis is different from meningitis. Meningitis means inflammation of the
protective layers that cover the brain. Sometimes patients have both meningitis
and encephalitis and this is called meningoencephalitis.
Symptoms
The types of symptoms seen in encephalitis reflect the specific areas of the brain
affected by inflammation. The range of symptoms and their rate of development vary
widely and can make the diagnosis of encephalitis difficult.
Encephalitis frequently begins with a ‘flu-like illness or headache. Typically
more serious symptoms follow hours to days later. The most serious finding is an
alteration in level of consciousness. This can range from mild confusion or drowsiness,
to loss of consciousness and coma.
Other symptoms include a high temperature, seizures (fits), aversion to bright lights,
inability to speak or control movement, sensory changes, neck stiffness, or uncharacteristic
behaviour.
Some people may also experience hallucinations and vivid nightmares during the acute
period of the encephalitis. These can be very distressing for the person concerned
and the family who may witness their distress. This phase usually ceases as the
inflammation and swelling of the brain subsides.
Last modified: 18 March 2008