title: Development of Isaacs' syndrome following complete recovery of voltage-gated potassium channel antibody-associated limbic encephalitis.
abstract: Autoantibodies against voltage-gated potassium channels (VGKC-Abs) are associated with acquired neuromyotonia (Isaacs' syndrome) and related disorders such as Morvan's syndrome and some cases of limbic encephalitis. The mechanisms underlying the various phenotypes induced by VGKC-Abs are not fully understood. Recently, we reported a case of LE with VGKC-Abs accompanied by severe intestinal pseudo-obstruction and thymoma. Thymectomy and immunosuppressive therapy induced dramatic clinical improvement of LE symptoms, and VGKC-Abs titers decreased from 1254 pM to 549 pM (normal>100 pM). Seventeen months later, the patient developed progressive generalized muscle cramping, paresthesias in his lower extremities, excessive sweating, and severe constipation. There was no recurrence of the LE. Electromyography showed fasciculation potentials and myokymic discharges, and the plasma VGKC-Abs titer was again elevated to 879 pM. Here we report a case of Isaacs' syndrome after complete remission of LE with VGKC-Abs that may provide an insight into a possible link among VGKC-Abs associated syndromes.
authors.affiliation: Department of Neurology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan. hirokatz_t@yahoo.co.jp
authors.forename: Hirokatsu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mori
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Sonoko
authors.initials: S
authors.lastname: Misawa
authors.forename: Setsu
authors.initials: S
authors.lastname: Sawai
authors.forename: Takamichi
authors.initials: T
authors.lastname: Hattori
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuwabara
mesh_terms: D000906:Antibodies / Q000378:metabolism*; D004576:Electromyography; D004660:Encephalitis / Q000150:complications / Q000276:immunology / Q000473:pathology; D006801:Humans; D020386:Isaacs Syndrome / Q000209:etiology*; D008032:Limbic System / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated / Q000276:immunology*
chemical_list: D000906:Antibodies; D024642:Potassium Channels, Voltage-Gated