Leucine-rich glioma-inactivated 1 (LGI-1) autoimmune encephalitis presenting as reversible cerebral vasoconstriction syndrome: Initial case report from India.

Thunderclap headaches and multifocal cerebral artery constrictions characterize reversible cerebral vasoconstrictive syndrome (RCVS). Leucine-rich glioma-inactivated 1 (LGI-1) autoimmune encephalitis (AE) presents as limbic encephalitis, hyponatremia, and faciobrachial dystonic seizures. Their unusual presentation concurrently is unknown. We describe a rare case of LGI-1 AE with RCVS. A 31-year-old lady presented with acute onset visual loss and encephalopathy on the background of sleep behavioral symptoms. Retrospectively, the patient complained of having muscle twitching, and mood changes. Her blood pressure was high (220/120 mm Hg). Blood investigations revealed hyponatremia and positivity for LGI-1+ and anti-amphiphysin 1+ antibodies. Neuroimaging initially showed features of RCVS. The cerebrospinal fluid study was unremarkable. Electromyography showed florid fasciculations with myokymic discharges. She was treated with steroids and responded to immunotherapy (Azathioprine). She maintained well into follow-up. AE is a great mimicker. Knowledge about atypical presentations is important for guiding treatment and further clinical course.