A 60-year-old woman was admitted 90 minutes after the onset of a typical transient global amnesia (TGA) episode, shortly after sexual intercourse. Anterograde amnesia was isolated and lasted less than 12 hours, with acute onset and progressive recovery. This patient had been referred 6 years before for a typical TGA, also postcoital. She regularly had moderate-intensity postcoital headaches.
Immediate fluorodeoxyglucose positron emission tomography (PET) scan (Figure 1A) revealed a pronounced left hippocampal hypometabolism (radiotracer was injected 2 hours after the onset of the symptoms). Magnetic resonance imaging (MRI) was performed 48 hours after TGA onset and showed a small nodular hyperintensity on diffusion-weighted imaging, with reduction of the apparent diffusion coefficient, in the left hippocampus (Figure 2). Fluid-attenuated inversion recovery and T2-weighted sequences were normal.
Gonzalez-Martinez V, Comte F, de Verbizier D, Carlander B. Transient Global AmnesiaConcordant Hippocampal Abnormalities on Positron Emission Tomography and Magnetic Resonance Imaging. Arch Neurol. 2010;67(4):510-511. doi:10.1001/archneurol.2010.50