Abstracts

Rationale: Seizures are a common symptom in autoimmune or paraneoplastic encephalitides. Particular phenotypes have been described with various antibody-related encephalitides to guide diagnostic testing with imaging, antibody testing, cancer screening, and electroencephalography. No definite guidelines regarding diagnosis or treatment have been established for autoimmune epilepsy.  We present a case of anti-CASPR2 antibody related autoimmune epilepsy.  Methods: Case report, information obtained by retrospective chart review Results: A 45 year-old woman without epilepsy risk factors presented with new onset generalized convulsions. Several events consisted of behavioral arrest and staring prior to the convulsion. She developed paresthesias in her feet and hands with exam findings consistent with neuropathy 18 months after seizure onset. Seizures persisted despite 3 anti-epileptic medications. She had multiple brain MRIs which revealed non-specific punctate T2 and FLAIR subcortical hyperintensities. EEG monitoring revealed left temporal focal slowing and sharp waves. No seizures were captured. Neuropsychological evaluation revealed mild cognitive impairment, particularly in executive functioning. A serum antibody panel yielded a positive CASPR2 antibody. She was initially treated with IV methylprednisolone and later IVIG every 3 weeks. The CASPR2 antibody was negative in the CSF (after immunotherapy) along with a normal CSF profile. Imaging of chest, abdomen and pelvis was unrevealing. Nerve conductions studies revealed borderline low sural sensory response amplitudes. She has been seizure-free and the signs of neuropathy improved since the addition of immunotherapy to her anti-epileptic medications. Conclusions: CASPR2 is a membrane protein which is expressed in both the CNS and PNS. CASPR2 antibody syndrome has been associated with a variety of symptoms including cognitive impairment, limbic encephalitis, peripheral nerve hyperexcitability, seizures, and pain syndromes, as well as Morvan syndrome.1, 3 It is rarely associated with tumors, most commonly a thymoma. It is responsive to immunotherapy. A recent 38 patient cohort1 of Caspr2-associated disease revealed a variable phenotype which includes cognitive disturbance (25%), epilepsy (24%), and neuropathic pain (18%), all of which were present in our patient. Eighty-nine percent of the cohort was male. MRI, EEG, EMG, and CSF results were variable and often normal. Our patient is a woman who exhibited several of the symptoms that are part of the CASPR2 phenotype, which has a broad spectrum and a variety of symptoms. Her positive antibody testing and response to immunotherapy are consistent with the presence of an autoimmune process.Reference: The clinical spectrum of Caspr2 antibody associated disease. Van Sonderen, A., Arino, H. et al. Neurology,2016; 87, 521-528From VGKC to LGI1 and Caspr2 encephalitis: The evolution of a disease entity over time. Autoimmunity Reviews, 2016, 15, 970-974Investigations of Caspr2, an autoantigen of encephalitis and neuromyotonia. Lancaster, E, Huijbers, M. et al. Annals of Neurology, 2011, 69, 303-311 Funding: None