Successful treatment of acute autoimmune limbic encephalitis with negative VGKC and NMDAR antibodies.
OBJECTIVE
To describe a case of acute nonherpetic limbic encephalitis (LE) with negative testing for antibodies directed against onconeuronal and cell membrane antigens, including voltage-gated potassium channels and N-methyl-D-aspartate receptor, that showed a dramatic response to immune therapy.


METHODS
A 30-year-old woman manifested generalized seizures, altered consciousness, and memory impairment shortly after a prodromal viral illness. Few days later the patient developed a drug-resistant epileptic status.


RESULTS
Electroencephalograph showed bitemporal slowing and paroxysmal slow wave bursts. Brain magnetic resonance imaging showed bilateral swelling in the medial temporal lobes. Cerebrospinal fluid analysis ruled out viral etiologies. A diagnostic search for cancer, including serum testing for known onconeuronal antibodies proved negative. Screening for cell membrane antigen antibodies, including voltage-gated potassium channels and N-methyl-D-aspartate receptor, was also negative. Suspecting an autoimmune etiology, we started an immunomodulatory treatment with intravenous immunoglobulin followed by a short course of oral prednisone, obtaining a full clinical recovery.


CONCLUSIONS
Our report confirms previous observations of "seronegative" autoimmune LE, suggesting the presence of other, still unknown central nervous system antigens representing a target of a postinfectious, autoimmune response in these patients. Moreover, it emphasizes the importance of early recognition and treatment of acute autoimmune LE, to reduce the risk of intensive care unit-related complications and the occurrence of permanent cognitive or behavioral defects.
Department of Neuroscience, Catholic University of Sacred Heart, Rome, Italy.
Anna
A
Modoni
Marcella
M
Masciullo
Pietro
P
Spinelli
Camillo
C
Marra
Tommaso
T
Tartaglione
Francesca
F
Andreetta
Pietro
P
Tonali
Gabriella
G
Silvestri
D000208:Acute Disease; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000927:Anticonvulsants / Q000627:therapeutic use; D001327:Autoimmune Diseases / Q000276:immunology / Q000523:psychology / Q000628:therapy*; D002462:Cell Membrane / Q000276:immunology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use*; D020363:Limbic Encephalitis / Q000276:immunology / Q000523:psychology / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008569:Memory Disorders / Q000209:etiology / Q000523:psychology; D009483:Neuropsychological Tests; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors* / Q000276:immunology*; D011241:Prednisone / Q000627:therapeutic use; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000276:immunology*; D012640:Seizures / Q000188:drug therapy / Q000209:etiology
D000893:Anti-Inflammatory Agents; D000927:Anticonvulsants; D016756:Immunoglobulins, Intravenous; D024642:Potassium Channels, Voltage-Gated; D016194:Receptors, N-Methyl-D-Aspartate; D011241:Prednisone