potentially treatable syndrome, but may respond to a variety of immunomodulatory agents, including IVIg. Limbic encephalitis — nonparaneoplastic There appears to be a role for IVIg in nonparaneoplastic limbic encephalitis associated with neuronal antibodies to cell surface antigens. This includes VGKC antibodies, as well as NMDA receptor antibodies and AMPA receptor antibodies. Limbic encephalitis — paraneoplastic IVIg may be indicated in select cases, in combination with tumour therapy (tumour resection and/or oncological treatment) where the latter has not led to an improvement in the neurologic syndrome; where other immunomodulatory therapies are milder forms and cases associated with CNS inflammatory lesions. is compelling evidence suggesting the role for IgG1 and IgG2 antibodies in binding to the GluN1 subunit of the NMDA-receptor. A proportion of cases are associated with underlying teratomas and tumour removal may be curative. Treatment thus consists of immunotherapy and tumour resection. First line immunotherapy typically includes intravenous methylprednisolone and IVIg or plasmapheresis. Due to the behavioural and/or autonomic manifestations of the disease, plasmapheresis, with large bore catheters may be clinically inappropriate. Second line treatment includes rituximab and cyclophosphamide. The consensus opinion is that one would progress to the addition of second line treatment in a standard case if no clinical improvement is observed after approximately two weeks of first line therapy and no tumour is found. are a variety of rarer neuroimmunological syndromes for which there is good evidence of antibodies binding physiologically relevant neuronal surface antigens with a case literature describing responses to immunotherapy often
Indications First line treatment for autoimmune encephalitis mediated by antibodies targeting neuronal cell surface antigens Qualifying Criteria Potassium channel antibody-associated encephalopathy Potassium channel antibody-associated neurologic syndromes include limbic encephalitis/subacute amnesic encephalopathy, Morvan syndrome, peripheral nerve hyperexcitability and autonomic ganglionopathy. Potassium channel antibody-associated encephalopathy is considered to be an autoimmune, nonparaneoplastic, potentially treatable syndrome, but may respond to a variety of immunomodulatory agents, including IVIg. Limbic encephalitis — nonparaneoplastic Clinical features consistent with antibody mediated autoimmune encephalitis including seizures, cognitive impairment, psychiatric symptoms, dyskinesias, autonomic instability, encephalopathy, catatonia, central hypoventilation AND A baseline assessment of function is measured by the Modified Rankin Score AND Neuronal antibodies to cell surface antigens have been demonstrated, unless tests results are unavailable. Note anti-GAD or thyroid antibody associated syndromes and the classical intracellular antineuronal antibodies are not considered this condition. IVIg is approved for one induction cycle (2g/kg over 5 days) in conjunction with systemic steroids Given that the symptoms vary with the antibody target, a description of the relevant symptoms for each patient will be captured together with a baseline assessment using the Modified Rankin Score: 0 - No symptoms at all 1 - No significant disability despite symptoms; able to out all usual duties and activities 2 - Slight disability; unable to carry out all previous activities, but able to look after own affairs without assistance 3 - Moderate disability; requiring some help, but able to walk without assistance 4 - Moderately severe disability; unable to walk without assistance and unable to attend to own bodily needs without assistance 5 - Severe disability; bedridden, incontinent and requiring constant nursing care and attention 6 Dead trial