Autoimmune Encephalitis and Epilepsy: Consider Immunotherapy?

There has long been recognized a somewhat distinct syndrome of limbic encephalitis with subacute onset of inflammatory CSF, memory disturbance, imaging changes, and temporal lobe seizures. More recently it has become clear that this syndrome is the tip of a much larger iceberg of autoimmune encephalitis associated with autoantibodies to neuronal antigens.

A variety of these syndromes have been described with varying association with particular autoantibodies. The best described is the syndrome associated with anti-NMDA receptors, which was recently well described by a sufferer of the illness. Affected patients frequently present with seizures, psychiatric syndromes, and memory disturbance: an abundance of clinical suspicion is needed to recognize the syndrome and to start the patient on the appropriate course of immunosuppression. It is also important to study these patients exhaustively to search for occult tumors, especially teratomas or neuroendocrine tumors (eg, small cell lung).

An interesting side feature of these recent revelations is the growing recognition that there may be patients with less full-fledged clinical syndromes who might have an autoimmune basis for their disease.

A recent series of patients reported in Neurology sheds an interesting perspective on this.¹ The authors collected patients with intractable epilepsy and some modest indication of autoimmunity based on the presence of one or more neural autoantibodies and a personal or family history of autoimmune syndrome. The researchers identified 29 patients who fit these criteria and tried to treat them with either intravenous steroids or IVIG: improvement of seizures was the endpoint. In this limited cohort, about 60% of patients had improvement and more than a third became seizure free.

This study is another of several over recent years showing that patients with autoimmune associated epilepsy may respond favorably to immunosuppression and that many of affected patients lack the full-fledged syndromes that have received so much attention.

My epilepsy specialist colleagues tell me that they look very carefully at every patient with intractable epilepsy who has features that suggest autoimmunity to determine whether a trial of immunotherapy is warranted.

1. Toledano M, Britton JW, McKeon A, et al. Utility of an immunotherapy trial in evaluating patients with presumed autoimmune epilepsy.
Neurology. 2014;82:1578-1586. http://www.ncbi.nlm.nih.gov/pubmed/24706013