Bilateral Hippocampal Infarction as Etiology of Sudden and Prolonged Memory Loss

Sudden memory loss, with prolonged cognitive deterioration, clinically initially resembling a transitory global amnesia (TGA)-like episode, might be caused by ischemic stroke in the hippocampal regions. We report a patient with TGA-type sudden anterograde amnesia and normal head CT. Examinations revealed that the patient had several vascular risk factors and 3 tesla (T) head MRI showed ischemic lesions in diffusion-weighted images (DWI) in both hippocampi. Neuropsychological assessment revealed sustained moderate verbal memory deterioration and abnormal executive functions. We suggest that small ischemic strokes in hippocampal regions might remain unrecognized and underdiagnosed if follow-up of TGA-type episodes is not adequate and if head CT remains the only method of brain imaging.