Autoimmune Encephalitis
This page has been compiled by the Encephalitis Society
Until recently in most cases of encephalitis the cause was unknown (over 50%). Now
a number of autoimmune types of encephalitis have been identified. The trigger in
some of these types of encephalitis is a tumour – which may be benign or carcinogenic.
The trigger could also be a viral infection but no specific viruses have been found.
Whatever the trigger, it causes the immune system to produce anti-bodies to a site
on nerve cells in the brain. The anti-bodies block the site and stop it from functioning
normally.
In Volted Gated Potasssium Channel Encephalitis (VGKCE) antibodies block
potassium channels that are vital for the control of electrical impulse that travel
along the nerve cell. Symptoms include memory loss and seizures.
In Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, antibodies block
a receptor that is necessary for nerve impulses to jump from one nerve cell to another.
In AMPAR Encephalitis, antibodies block the alpha-amino-3-hydroxy-5-methyl-4-
isoxazolepropionic acid receptor.
NMDA and AMPA receptors are important in establishing neural networks that form
when we learn something new, remember an event and think through a problem. Symptoms
in adults may include anxiety, agitation, paranoia, and visual or auditory hallucinations.
In younger children parents described temper tantrums, behavioural change, agitation,
aggression, and progressive speech deterioration as initial symptoms.
Encephalitis lethargica (EL) syndrome may be triggered by a streptococcal
infection with antibodies blocking nerve function in the basal ganglia causing sleep
disorder, lethargy and neuropsychiatric disturbances.
Diagnosis will require a specialist laboratory to identify the antibodies concerned
and a detailed MRI scanner to find any tumours. Treatments include steroids to slow
down the production of antibodies and plasma exchange to remove antibodies. If a
tumour is found surgery will be required to remove it.
Increasing success in the recognition, diagnosis and treatment of autoimmune encephalitis
has resulted in improved recovery.
Last modified: May 2010