Chronic limbic encephalitides

Limbic encephalitis (LE) was described in the seventh decade of the 20(th) century as a clinical-pathological syndrome in adults. Initially, the paraneoplastic form was in the center of interest. The demonstration of autoantibodies in patients' sera, which react with brain cells (and tumor cells), represented an important diagnostic progress. On the one hand, antibodies against intracellular antigens, on the other hand against cell membrane antigens ("neuropil antibodies") have been found in cases with paraneoplastic LE. Lately, the impact of the non-paraneoplastic cases has been acknowledged. In a part of these patients, the serum antibodies against voltage-dependent potassium channels (VGKC antibodies) have been detected. The characteristic MRI course of LE patients has recently been described in detail: Hippocampal swelling and T2-/FLAIR-signal increase are early findings. After some months, swelling regresses and hippocampal atrophy comes about with continuous signal increase. There has not yet been an agreement on formal diagnostic criteria for all LE-subsyndromes. In this article, such diagnostic criteria are proposed. The therapy with immunosuppressive or immunomodulating substances is usually without effect in paraneoplastic LE cases with antibodies against intracellular antigens. Successes in the sense of clear improvements are achieved in the LE forms associated with VGKC and neuropil antibodies.