Potentially reversible autoimmune limbic encephalitis with neuronal potassium channel antibody

Abstract

Voltage-gated potassium channel antibodies are a valuable serologic marker of a potentially reversible autoimmune encephalopathy. The neurologic manifestations of this disorder are indistinguishable from paraneoplastic limbic encephalitis but are distinct from Morvan syndrome and Hashimoto encephalopathy.

The Emerging Link Between Autoimmune Disorders and Neuropsychiatric Disease

“…32 A classic limbic encephalitis previously thought to be caused by autoantibodies recognizing voltage-gated potassium channels (VGKC) is now known to result from autoantibodies targeting LGI1. 30,33 As described in detail as encephalitis attributed to anti-VGKC antibodies, 34 anti-LGI1 patients present most prominently with seizures, memory loss, and confusion. Other symptoms can include autonomic dysfunction (hyperhidrosis, hypersalivation) and behavioral changes such as apathy and irritability.…”

“…Like other autoimmune encephalopathies with extracellular antigen targets, anti-LGI1 encephalitis responds remarkably well to immunotherapy, with ~80% of patients showing either full recovery or mild disability. 34,35 …”

Association of severe myoclonic epilepsy of infancy (SMEI) with probable autoimmune lymphoproliferative syndrome-variant

“…29,42,47 The genetically induced FAS pathway deficiency may have predisposed our DALD patient to the development of organ-specific autoimmune autoantibody production and thyroideal disease with possible involvement of cytotoxic mechanisms mediated by FAS-FASL pathway. The presence of antimicrosomal antibodies, associated with hypothyroidism, slowing of EEG background activity, diffuse mild brain atrophy, neuropsychological sign, 48 improved epileptic activity after cortisone, could suggest a direct effect of IgG-mediated antimicrosomal antibodies, possibly due to a common brain-thyroid antigen 49,50 involving neurons and glia (Hashimoto encephalopathy). 32 However, the low titre of anti-microsomal antibodies may also demonstrate a unique predisposition to develop multiple antibodies.…”

A Case of Encephalitis Secondary to NMDA Receptor Antibody with Concurrent Striational Antibodies and Thymic Hyperplasia

“…Various other synaptic antibodies have also been associated with autoimmune encephalitis. These include: anti-leucine-rich gliomainactivated protein (LGI1), anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPAR), anti-gamma-aminobutyric acid (GABA-B) receptor, and anti-contactin-associated protein 2 (CASPR-2) [2]. Symptoms of NMDAR encephalitis may vary but are most commonly associated with progressive cognitive decline, psychiatric symptoms, and even seizures [3,4].…”

“…To our knowledge, the exact mechanism of why these antibodies cause encephalitis is currently unknown; however, paraneoplastic anti-NMDAR encephalitis cases have been most commonly associated with ovarian teratomas [2,5,6]. Other uncommon tumor sources include thymus, lung, breast, testis [7], and lymph nodes [5].…”