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Autoimmune disorders are conditions that occur when the immune system (the body’s defence system) attacks the body’s own tissues as if they were foreign. Our immune system’s essential function is to continually patrol the body for foreign invaders, such as viruses and bacteria, and other substances that are injurious to health, then eliminate them.  The down side is the potential for our immune system to mistake something that is part of ourself as harmful.  This inappropriate immune response is known as autoimmunity and leads to destruction of healthy tissue or changes in how cells function.

 

ADEM (Acute disseminated encephalomyelitis) is a type of autoimmune encephalitis that has been known for some time.  It occurs relatively soon after an acute viral infection and is also called Post-infectious encephalitis. It is more common in children than adults.   Immune cells attack myelin, which covers nerves, because it “looks like” the virus they are fighting.  Destruction of myelin slows down the rate at which an impulse is transmitted along nerves.  Although a serious illness, it is usually short lived with a good recovery.

 

Many types of Autoimmune Encephalitis have only become understood recently.   It is now known that there are many causes of encephalitis associated with autoantibodies.  The autoantibodies target areas on the outside of nerve cells which changes how the nerves function, especially how they transmit nerve impluses.  These types of autoimmune encephalitis are given the biochemical names of their targets which can be long and complex. They include autoantibodies that target channels on the surface of nerves (VGKC complex antibodies short for “volted gated potassium channel complex antibodies”) and autoantibodies that target receptors at nerve endings (NMDA short for “ Anti-NMDA (N-methyl D-aspartate) receptor antibody”, AMPA  short for “ alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antibody”, and GABAB short for “ γ-Aminobutyric acid-B receptor antibody”).  The trigger that causes autoantibodies to be produced cannot always be found.

 

The term paraneoplastic encephalitis is used for autoimmune encephalitis where cancer has triggered the autoantibodies.  Finding and removing the tumour is an essential part of the treatment.

This information is taken from the Book “Understanding Encephalitis” by Elaine Dowell.  The book is available from Amazon Understanding Encephalitis.

 

ARTICLES AND RESEARCH PAPERS

Links are to a pdf if the article is free and to the Pubmed page is the article is not free

Neuroimmunology: an expanding frontier in autoimmunity. Abstract – Anti-neuronal autoimmune encephalitis (AIE) comprises a recently characterized group of immune-mediated disorders that result in limbic, multifocal, or diffuse encephalitis due to direct interaction of autoantibodies with neuronal surface or synaptic proteins. The pathological effects of the autoantibodies vary according to the target antigen but when they are removed, neuronal dysfunction is commonly reversed. Ongoing research on AIE constantly increases the number of novel autoantibodies and expands the spectrum of neurological syndromes that are important in the differential diagnosis of psychiatric illness, dementia, or viral encephalitis. This review summarizes recent advances in AIE, focusing on pathogenetic mechanisms and novel associations with other CNS disorders such as neurodegeneration, relapsing symptoms post-herpes simplex virus encephalitis, and demyelinating diseases. In addition, an algorithmic approach to detect and characterize neuronal cell surface autoantibodies is proposed.  Neuroimmunology an expanding frontier in autoimmunity

Central nervous system neuronal surface antibody associated syndromes: review and guidelines for recognition. Abstract – The concept of antibody mediated CNS disorders is relatively recent. The classical CNS paraneoplastic neurological syndromes are thought to be T cell mediated, and the onconeural antibodies merely biomarkers for the presence of the tumour. Thus it was thought that antibodies rarely, if ever, cause CNS disease. Over the past 10 years, identification of autoimmune forms of encephalitis with antibodies against neuronal surface antigens, particularly the voltage gated potassium channel complex proteins or the glutamate N-methyl-D-aspartate receptor, have shown that CNS disorders, often without associated tumours, can be antibody mediated and benefit from immunomodulatory therapies. The clinical spectrum of these diseases is not yet fully explored, there may be others yet to be discovered and some types of more common disorders (eg, epilepsy or psychosis) may prove to have an autoimmune basis. Here, the known conditions associated with neuronal surface antibodies are briefly reviewed, some general aspects of these syndromes are considered and guidelines that could help in the recognition of further disorders are suggested. Central nervous system neuronal antibody associated syndromes review and guidelines

Neuronal surface antibody-mediated autoimmune encephalitis.  Abstract – In the past few years, many autoimmune encephalitides have been identified, with specific clinical syndromes and associated antibodies against neuronal surface antigens. There is compelling evidence that many of these antibodies are pathogenic and most of these encephalitides are highly responsive to immunotherapies. The clinical spectra of some of these antibody-mediated syndromes, especially those reported in only a few patients, are evolving. Others, such as anti-N-methyl-D-aspartate (NMDA) receptor encephalitis, are well characterized. Diagnosis involves recognizing the specific syndromes and identifying the antibody in a patient’s cerebrospinal fluid (CSF) and/or serum. These syndromes are associated with variable abnormalities in CSF, magnetic resonance imaging, and electroencephalography. Treatment is often multidisciplinary and should be focused upon neutralizing the effects of antibodies and eliminating their source. Overlapping disorders have been noted, with some patients having more than one neurologic autoimmune disease. In other patients, viral infections such as herpes simplex virus encephalitis trigger robust antineuronal autoimmune responses.  http://www.ncbi.nlm.nih.gov/pubmed/25369441

Dazed, confused, and asystolic: possible signs of anti-N-methyl-D-aspartate receptor encephalitis. Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare panencephalitis that can present with severe cardiac dysrhythmias. We present a case of a 19-year-old woman with no significant medical history who presented with progressive changes in mental status and profound ictal asystole that necessitated the placement of an external temporary pacemaker. She was diagnosed with and treated for anti-NMDA receptor encephalitis, and she recovered after a prolonged and complicated hospitalization. We review the pathophysiology and management of anti-NMDA receptor encephalitis, as well as its cardiac manifestations.  Dazed confused and asystolic possible signs of ANMDA encephalitis