Autoimmune Limbic Encephalitis in a Patient with Acute Encephalopathy and Hyponatremia

Acute encephalopathy is a common clinical presentation for hospital admissions. Autoimmune encephalitis is a rare cause of encephalopathy which has increasingly been recognized over the last decade. The detection of various neuronal antibodies has helped diagnose these syndromes, but they have limited availability, mostly in the developed countries. We present a case of a middle-aged female presenting with memory impairment, gait disturbances, and hyponatremia. A clinical diagnosis of autoimmune limbic encephalitis was made based on faciobrachial dystonic seizures, SIADH, and MRI changes 10 days prior to autoantibody titer returned. Prompt treatment with steroids and intravenous immunoglobulin was started with improvement in her neurological symptoms. This case highlights the importance of considering autoimmune encephalitis syndromes in the differential diagnosis of patients with classical neurological presentations and prompt diagnosis and immunotherapy to improve neurological outcomes.