PT - JOURNAL ARTICLE AU - Jonathan E Attwood AU - Saniya Naseer AU - Sophia Michael AU - Josie Riley TI - Clinical diagnosis of LGI1 antibody encephalitis in an 83-year-old woman AID - 10.1136/bcr-2020-237398 DP - 2021 Jan 01 TA - BMJ Case Reports PG - e237398 VI - 14 IP - 1 4099 - http://casereports.bmj.com/content/14/1/e237398.short 4100 - http://casereports.bmj.com/content/14/1/e237398.full SO - BMJ Case Reports2021 Jan 01; 14 AB - An 83-year-old woman was referred to hospital with a 2-week history of short-lived episodic unpleasant sensations in her head and running down her body. This was accompanied by new short-term memory impairment and arm spasms. Initial investigations including blood tests and brain imaging did not reveal the diagnosis. The patient developed an increasing frequency of abnormal movements of her face and arm. These were clinically recognised as faciobrachial dystonic seizures (FBDS). FBDS are pathognomonic of an autoimmune encephalitis caused by an antibody directed against leucine-rich glioma-inactivated 1 (LGI1). The clinical diagnosis resulted in treatment with immunotherapy, leading to cessation of seizures and rapid cognitive recovery. Later, the predicted serology was confirmed. This reversible and under-recognised cause of cognitive impairment, typically affecting elderly patients, can be diagnosed clinically to enable early and effective treatment.