097 A rare case of recurrent transient global amnesia

Abstract

IntroductionTransient global amnesia (TGA) is a clinical syndrome characterised by the sudden onset of anterograde amnesia accompanied by repetitive questioning, sometimes with a retrograde component, lasting up to 24 hours, without compromise of other neurologic functions.CaseA 71 year old male presented to the neurology clinic with history of recurrent episodes of reversible anterograde amnesia with repetitive questioning. His first two episodes were in May 2016 and clinically very typical of TGA. After that he had recurrent episodes and he noted that they were happening on a monthly basis. He had an episode on 24 March 2017 at Yangon airport as he was returning from a trip to Myanmar. He had had three episodes in February 2017 and two in March and April 2017 and one episode on 20 May 2017. Initial MRI brain showed frontotemporal atrophy suggestive of Alzheimer’s disease and there was hypo-perfusion on the nuclear medicine study. EEG did not show any epileptic activity. His partner described a typical episode where the patient lost his memory for the preceding 24 hours and he had repetitive questioning such as ”what day is it” repeatedly. During the entire episode, he was conscious and able to converse appropriately. He had another episode of amnesia on 19 August and was admitted and underwent an MRI of brain, which showed characteristic punctate abnormalities in the bilateral hippocampi on B2000 DWI.ConclusionThe estimated annual rate of recurrence of TGA is 5.8%. Diagnosis is made from typical clinical features and typical MRI DWI findings of punctate lesions in the hippocampal with a DWI resolution of B=2000, and a thin slice thickness of 2 to 3 mm. Our patient had 11 documented episodes of transient amnesia and was a diagnostic dilemma until the characteristic hippocampal abnormalities were demonstrated on MRI.