One of the things I noticed in everything I read about both infectious and autoimmune encephalitis, is whilst almost everywhere it describes that
with infectious encephalitis the virus attacks the brain and with autoimmune encephalitis the immune system attacking the brain.
However I just wondered how the virus overcomes the blood brain barrier and the same with the immune system, which as I understand it are locked out normally from the brain. Can anyone give me more information or direct me to where I can look this up
Apologies if I have just missed it but I really like to understand how these things work, where I can.
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A factsheet on the Encephalitis Society websit called HowThe Brain Works written by the CEO of the Encephalitis Society Dr Ava EastonEaston.
The Brain And Infection
The brain is protected by a blood-blood-brain barrier which prevents any large molecule passing from the blood into the brain. The blood-blood-brain barrier acts very effectively to protect the brain from many common infections. Thus infections of the brain are very rare.
The outcome of any infection is dependent upon the ability of the infection to cause disease and the response of the immune system. The immune response protects organisms against injury and infection by developing white blood cells to site of injury to kill potential pathogens and promote tissue repair. However, the powerful inflammatory response also has the capacity to cause damage to normal tissue.
Unfortunately the immune response to an infection of the brain can contribute more to the disease process than the infection itself.
The Brain And Encephalitis
In infectious encephalitis, viruses entering nerve cells called(neurons) utilise components of the cell in order to replicate (make copies of themselves). This uses up energy stores and oxygen, damaging the cell.cell.In post-post-infectious/autoimmune encephalitis it is the immune system that causes damage to neurons or other brain cells. In both types of encephalitis, by-products of the immune system'system's actions (fluid, white blood cells, the contents of the dead nerve cells and disabled viruses) can significantly alter the fluid surrounding neurons and after their functioning. Cell deaths causes a fluid build up in the brain. This can cause increasedincreas pressure within the skull sometimes causing reduced consciousness. The extra unwanted fluids build up rapidly, and glial cells (cells that support the neurons) try to absorb the unwanted chemicals and fluids in order to protect neurons from harm, and in the process they swell up too. Glial cells act as sponges and scavengers of toxic by-products, caused by the inflammation but when they become overloaded, they die and then release the toxic chemicals back into the fluid, where they kill additional neurons. The extremely high levels of these substances are sufficient to kill vulnerable and weakened neurons by damaging their membranes or by exciting them to a point where they "burn out".
At the site of inflammation and in nearbynea tissue, there is biological chaos as the brain tries to adjust and fight the consequences of the damage. The dying cells give off chemicals that activate macrophages (white blood cells), which move the bloodstream into the injury area, to absorb and eliminate debris. Glial cells and their helpers, which have gathered at the site to clean it up, now begin to form the scar tissue that will remain a part of the brain'brain's new architecture. Sometimes the glial barriers prevent healthy, remaining neurons from restoring atonal connections. In other cases, nerve terminals cannot pass the scar, and abnormal activity is then generated that can lead to epileptic seizures.
Thank you Paula. I really appreciate you taking the time. I thought I had covered most articles but missed this one. At the moment just trying to understand as much as Ican.
I was told that although I’d never had a cold sore on my lip, apparently I’d always carried the herpes simplex virus in my system . When I was very rundown, the virus bypassed my mouth and travelled up in my blood system past my left ear and into my brain into the front temporal lobe. where vital functions like my short-term memory existed.
Apparently the brain is a perfect location for the virus, being warm and moist. It spreads there rapidly , so that’s why it’s such a nightmare for our bodies to overcome.
Apologies if there are any medical inaccuracies in that description. But you get the gist . 😊
I didn't hhave a cold sore either so my Dad said, but he did say that a Fri of the family had a big cold sore at my first birthday party and everyone was hugging and kissing me , then the next day I took ill and I was rushed to hospital , they diagnosed me with Viral Encephalitis and Status Epilepticus at the same time. I only found out it was frontal lobe epilepsy ten years ago because the OCD specialists wanted to try me on new OCD medication but I had to see a neurologist first to see if I was still epileptic at the time and apparently I was and in the letter I received back it said I had a right sided spike whatever that'that's supposed to mean.
I always say to my friends now that they're lucky if they have a coldsore, as the virus is better in their lips than in their brain. I hope the Drs have found the right meds to control your epilepsy, Paula. I've been seizure free for over 2 years now, but epilepsy has been one of the hardest long term effects of encephalitis for me to deal with .
Wow. Thank you for the explanation HSE_Survivor. Thats another thing I hadnt considered whether it targeted a specific area of the brain. I just keep learning (Thank you all)
I was going to suggest the Encephalitis Society website too but Paula has copied and pasted a fab explanation! 🥰 some of this I hadn’t realised or thought about before. Hope you are ok 👍👍👍
Paula’s reply explains it so well. And also HSE Survivor has explained the passage of the herpes simplex virus to the brain that I was told although someone explained it to her better than it was to me! Thanks for asking this. I’m learning too.
Wow Gandalf, Thank you so much. Whilst (as all these topics do) that raised a few more subjects for me to investigate, that was incredibly informative and very specific. I also love the associated embedded video on the blood-brain barrier:-
fantastic. Thanks again. The site itself also looks very informative.
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