What are the dreadful autoimmune disorders that plague neurology?

Neurologists have always known that autoimmunity accounts for many nervous system disorders. A classical example is Sydenham’s chorea or St Vitus dance. This movement disorder develops after rheumatic fever, and is caused by antibodies to the bacterium called Streptocccus. The modern-day resurrection of this condition is called paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections. I know, too long, but just call it PANDAS. A great acronym I must say, quite unlike ABGA which stands for anti basal ganglia antibody syndrome, an umbrella term for many movement disorders provoked by external agents.

Prague. Pedro Szekely on Flikr. https://www.flickr.com/photos/pedrosz/3806301921
Prague. Pedro Szekely on Flikr. https://www.flickr.com/photos/pedrosz/3806301921

Neurologists are also comfortable with the knowledge that primary autoimmune disorders affect the nervous system. Prominent here are the neuropsychiatric features of systemic lupus erythematosus (SLE). SLE also presents with movement disorders such as chorea, amongst many other features. Similarly, there are diverse neurological manifestations of the anti-phospholipid antibody syndrome.

By Gentaur - Gentaur, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7222221
By Gentaur – Gentaur, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7222221

A third group of neurological diseases are more sinister because the antibodies are generated by cancer cells. These paraneoplastic neurological syndromes are legion and protean, requiring a high index of suspicion to diagnose. Most frustrating for neurologists is that the cancer itself may not emerge for several years after the diagnosis of a paraneoplastic syndrome. Notorious for this cloak and dagger behaviour is small cell lung cancer (SCLC). Because of the potential consequences, neurologists deploy their heavy duty imaging scans such as positron emission tomography (PET) scans. They then lie low, year after year, waiting to nab the devious cancer as soon as it shows up.

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In recent years, a completely different class of disorders has attained notoriety and infamy in the form of autoimmune encephalitis. These disorders often pretend to be infectious diseases, but they totally disregard the antibiotics and antiviral agents the neurologist attacks them with. By subterfuge and subversion they disable ion channels and receptors to cause havoc in the brain. And nobody has described such havoc better than Susannah Cahalan in her book Brain on Fire: My Month of Madness.

 

Autoimmune encephalitis may fester for weeks, years or decades, evading detection by its duplicitous behaviour, and by the increasing number of antibodies that may be responsible. There are however three main culprit antibodies which neurologists are now getting a grip on:

  • Voltage gated potassium channel (VGKC)
  • N-methyl-d-aspartase (NMDA)
  • α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)

These conditions are all potentially fatal but eminently curable; this underlies the importance of recognising and treating them very early. A recent paper in Lancet Neurology summarises the clinical approach to autoimmune encephalitis (pdf).

 

B0007683 Ion channels. Wellcome Images on Flikr. https://www.flickr.com/photos/wellcomeimages/5814248573
B0007683 Ion channels. Wellcome Images on Flikr. https://www.flickr.com/photos/wellcomeimages/5814248573

 

Autoimmune neurology is a rapidly evolving field. I will review recent developments in this area in a second post to follow shortly titled What’s breaking at the cutting edge-of autoimmune neurology?

6 thoughts on “What are the dreadful autoimmune disorders that plague neurology?

  1. A fascinating article Dr. Ibrahim. My sister died last January of SCLC. She developed Discoid Lupus in 2010, but was only dx with SCLC less than a year prior to that. We always wondered what the tie-in was. Would it be fair to say autoimmune is the preemptive state of more serious disease?
    Many thanks!

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  2. Thank you for this…I currently am being treated for my diagnosed disease of Anti-Nmda Receptor Encephalitis… this is a horrible disease to go through and it is my hopes that when I am better, I will also be able to help spread awareness to these types of diseases like Susannah Cahalan.

    Liked by 1 person

  3. Thank you for writing this post. In the last three months my 8-year-old son has been diagnosed with PANDAS by an immunologist, PANS by an infectious disease doc and Sydenham Chorea by a neurologist. As a mom (and an ardent researcher), I’m trying to wrap my head around all of this. His symptoms and presentation most closely resemble Sydenham, but these all seem to be the same disease with different patient expressions, especially given that treatment options are basically the same. I think the main differences are how insurance companies covers treatments, which is why I’m strangely grateful for the Sydenham diagnosis.

    So far treatment response has been mixed. He responded mildly positive to antibiotics with a slight reduction in symptoms. Tonsil removal showed more progressive improvement. But the recent addition of high-dose steroid burst (after non-remarkable MRI) has set him back significantly, which is disheartening.

    As much as I hate the idea of pooled blood products, I’m guessing that IVIG or plasmapheresis is in his near future.

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    1. My sympathies Berta. Indeed IVIg is from pooled blood but it is so well-treated that the risks of infection are negligible. And it is good treatment with less side effects than plasmapheresis. Unfortunately I can’t comment on your son’s specific diagnosis

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