Limbic encephalitis

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Classification according to ICD-10
G13.1 Other system atrophies, mainly affecting the central nervous system, in neoplasms
ICD-10 online (WHO version 2019)

Limbic encephalitis (singular: limbic encephalitis ) are a group of inflammatory diseases of the central nervous system . Memory disorders , psychiatric abnormalities and epileptic seizures are characteristic of these subacute diseases, which usually occur in adults .

The term "limbic encephalitis" was coined in the 1960s by British neuropathologists and neurologists who found inflammatory changes mainly in areas belonging to the limbic system in the autopsy of patients .

classification

Limbic encephalitis is associated with cancer in around 60 percent of cases . These are then referred to as paraneoplastic limbic encephalitides (PLE), from which the non- paraneoplastic limbic encephalitides (NPLE) are distinguished. The non-paraneoplastic limbic encephalitides are either autoimmune diseases or the mechanisms by which the disease develops are not known.

Non-paraneoplastic limbic encephalitis (NPLE)

An NPLE is used when the clinical and imaging criteria of limbic encephalitis are met, but no tumor can be found despite extensive tumor search. The NPLE can also be associated with autoantibodies. The antibodies in the NPLE are mostly directed against structures on the surface of nerve cells, while the antibodies in the PLE are mostly directed against intracellular structures. Well-known antibodies that can be associated with NPLE are VGKC, NMDA , AMPA and GAD antibodies.

Investigation methods

Diagnostic criteria

In 2008 diagnostic criteria were defined as a prerequisite for the diagnosis of limbic encephalitis. The basic requirement is the occurrence of a limbic syndrome with the onset of symptoms less than 5 years ago. The occurrence of at least one of the following three symptoms defines the limbic syndrome: a disorder of the new memory, temporal lobe seizures and / or an affect disorder. In addition, temporomedial signal increases in the FLAIR / T2 weighting can be detected in magnetic resonance imaging of the brain.

The definitive diagnosis of limbic encephalitis can be made according to the criteria if chronic temporomedial encephalitis can be detected histologically, a tumor has been detected within 5 years of the onset of neurological symptoms, or well-characterized onconeuronal antibodies or antibodies against VGKC can be detected .

If the basic requirements are met but the criteria for a definitive diagnosis are not met, the clinical picture can be classified as possible limbic encephalitis if the MRI follow-up examination shows a decrease in volume and signal of the temporomedial swelling and signal increase. The signal increase in the MRI should not be due to a status epilepticus. The signal increase normalizes in status epilepticus within a few days.


CSF examination

The nerve fluid ( liquor cerebrospinalis ) obtained by a lumbar puncture shows inflammatory changes in up to 80% of limbic encephalitides. Typical is an increase in lymphocytes (lymphocytic pleocytosis ), an increase in protein , a slight barrier disruption , evidence of intrathecal IgG formation and occasionally evidence of oligoclonal bands . Antineuronal antibodies can be detected in both CSF and serum. The antibody concentration in the CSF can be significantly higher.

treatment

For both paraneoplastic and non-paraneoplastic limbic encephalitis, the start of immunotherapy is recommended when there is “clinically sufficient suspicion”, especially if this is supported by the brain MRI findings. Possible immunotherapies are therapy with glucocorticoids , with immunoglobulins or performing plasmapheresis .

If the results of the tumor and antibody search are available, the therapy is adjusted accordingly. If a tumor is detected, the focus is on its treatment. If there is no evidence of a tumor, it is recommended to check the result of the immunotherapy after 3 months and to switch to another form of immunotherapy if there is no response. If there is no response after a further 3 months, it is recommended that immunotherapy only be continued if VGKC antibody-associated limbic encephalitis is involved.

literature

  • Anna-Lena Cordes, Martin Stangel: Limbic encephalitides . In: Martin Stangel, Matthias Mäurer: Autoimmune diseases in neurology. Diagnostics and Therapy Springer, 2011, ISBN 978-3642204760 , pp. 89-97

Review article

Individual evidence

  1. ↑ Anna-Lena Cordes, Martin Stangel: Limbic encephalitis . In: Martin Stangel, Matthias Mäurer: Autoimmune diseases in neurology. Diagnostics and Therapy Springer, 2011, ISBN 978-3642204760 , p. 94
  2. ↑ CG Bien: Chronic encephalitides as causes of epilepsy: pathogenesis, diagnosis and therapy. In: Current Neurology. 35, 2008, pp. 214-224, doi : 10.1055 / s-2008-1067419 .
  3. ↑ a b c d e Immune-mediated diseases of the gray matter of the CNS and neurosarcoidosis , guideline of the German Society for Neurology
  4. ↑ Anna-Lena Cordes, Martin Stangel: Limbic encephalitis . In: Martin Stangel, Matthias Mäurer: Autoimmune diseases in neurology. Diagnostics and Therapy Springer, 2011, ISBN 978-3642204760 , p. 92