Voltage Gated Calcium Channels Antibody-Associated Autoimmune Encephalitis (P5.228)

Background Voltage Gated Calcium Channels (VGCC) of the P/Q subtype have been linked to Lambert Eaton Myasthenic Syndrome and Familial Hemiplegic Migraine, but to date have not been associated with autoimmune encephalitis. Voltage Gated Potassium Channels (VGKC) on the other hand have been associated with encephalitis and some cases of drug resistant epilepsy. This is the first case to demonstrate autoimmune encephalitis and seizures in a patient with VGCC antibodies Case presentation A 39 year old female patient presented with a left homonymous hemianopsia. A brain MRI revealed a right occipital hyperintense lesion seen on DWI thought to represent a cryptogenic stroke. One month later, the patient was re-admitted with right hemiparesis and found to have new GAD enhancing lesions in the left frontal and parietal parasagittal region. During this admission the patient became acutely encephalopathic. Video EEG recorded seizures with a focus originating from the left frontal hemisphere. Infectious studies, including all CSF virus panels were negative. A brain biopsy revealed cortical laminar necrosis with the presence of mononuclear inflammatory cells. An extensive vasculitic, autoimmune and paraneoplastic work-up were completed and was remarkable for highly elevated VGCC P/Q type antibodies. CT chest, abdomen, and pelvis followed by PET scan were unremarkable. A diagnosis of an autoimmune encephalitis was established. After receiving a course of high dose IV steroids and plasmapheresis the patient demonstrated marked improvement in her strength and resolution of seizures. Conclusion This case demonstrates a correlation between a high titer of VGCC antibodies and autoimmune encephalitis. Our patient9s initial improvement with steroids and plasma exchange in the face of a negative CT and PET suggests a primary autoimmune process rather than a paraneoplastic etiology, though we admit that it is premature to rule out remission and we will continue to follow her Disclosure: Dr. Alwaki has nothing to disclose. Dr. Lugo has nothing to disclose. Dr. Goshgarian has nothing to disclose. Dr. Ahmad has nothing to disclose. Dr. Hefzy has nothing to disclose. Dr. Mitsias has nothing to disclose.