encephalopathy (also sometimes called “autoimmune encephalitis”) occurs when a person’s own immune system
mounts a defense (autoimmune) against parts of that person’s own brain, leading to pathological damage to the brain
(encephalopathy). Autoimmune encephalopathies comprise a large number of
syndromes, many of which have only recently been identified. Unfortunately,
for many years, such syndromes were not readily classified, and many persons who mounted these immune responses were not treatable. Indeed, many were considered delusional and were institutionalized. Fortunately, today, there are many treatments for this diverse set of syndromes, even when the underlying
cause is not known.|
these syndromes, a person’s own immune system mounts an immune response to portions of the person’s own brain.
Among the results of this unusual response is the production of autoantibodies (antibodies against one’s own self).
As part of this immune response, as with many other immune responses, swelling occurs. In this case, the swelling is
within the substance of the brain. This swelling disrupts the normal processing within the brain, and can lead to a
variety of symptoms, including, for example, (1) inability to process simple information; (2) inability to keep track of time;
(3) delusions – believing things that are completely untrue, yet you believe to be true and (4) paranoia – irrationally
believing that people and the environment are actively working against you and may harm you.
Many types of autoimmune encephalopathies have been described.
Indeed, because of this wide spectrum, the disorder itself is difficult to classify. However, finding a specific autoantibody
in the person’s blood can identify some disorders. Among these syndromes are those where a person mounts an immune
response and produce autoantibodies to their own nervous system components that are vital for processing various types of
nervous activities within the brain. These include a receptor for the neurotransmitter glutamate, the NMDA (N-methyl-D-aspartic
acid) receptor, and an ion channel that is important for neuronal communication, the potassium channel. Presence of
autoantibodies to these types of components of the nervous system is consistent with these types of autoimmune encephalopathies.
encephalopathies also exist such as post-infectious encephalitis. These encephalopathies are not triggered by a person
mounting an immune response to their own body; rather, they are a result of a delayed response following a person’s
immune response to an infection. These may follow a mild viral infection or may, in rare cases, result from an immune
response to a vaccination.
Another autoimmune encephalitis key group is paraneoplastic neurological syndrome. This is described as the response
of cancer-fighting agents in the body’s immune system fighting against tumor cells in the body. This disorder may arise
from tumor or from immune cross-reactivity between malignant and normal tissues Treatment of the underlying cancer and other
interventions may prevent further damage, improve symptoms and result in better quality of life.
For general information about autoimmune encephalopathies, go to: http://www.nhs.uk/Conditions/Encephalitis/Pages/Causes.aspx and
Specific information may be found at:
Vernino S, Geschwind M, Boeve B. (2007) Autoimmune encephalopathies. Neurologist 13: 140-47. PMID: 17495758
Schiess N, Pardo CA. (2008) Hashimoto's encephalopathy. Ann N Y Acad Sci 1142: 254-65. PMID: 18990131
Dalmau J. (2008) Limbic encephalitis and variants related to neuronal cell membrane autoantigens. Rinsho Shinkeigaku
48: 871-4. PMID: 19198103
Moscato EH, Jain A, Peng X, Hughes EG, Dalmau J, Balice-Gordon RJ. (2010) Mechanisms underlying autoimmune synaptic encephalitis
leading to disorders of memory, behavior and cognition: insights from molecular, cellular and synaptic studies. Eur J
Neurosci 32:298-309. PMID: 20646055
Demaerel P, Van Dessel W, Van Paesschen W, Vandenberghe R, Van Laere K,
Linn J. (2011) Autoimmune-mediated encephalitis. Neuroradiology 53: 837-51. PMID: 21271243 Flanagan EP, Caselli RJ. (2011) Autoimmune encephalopathy. Semin Neurol
31:144-57. PMID: 21590620