Homonymous Visual Field Deficit Selected Ischemic Stroke as The Etiology of Transient Amnesia

Transient global amnesia (TGA), coined by Fisher and Adams over half a century ago, is an episodic, idiopathic neurological event with good prognosis that presents as a diagnostic challenge, particularly among patients with known stroke risk factors in the first hours after the onset of amnesia. Hypothesis surrounding TGA etiology includes acute ischemia involving the hippocampus - often presenting as discrete restricted DWI MRI hyperintensity - venous congestion, migraine, seizures, or strenuous activity. Published TGA MRI findings include uni or bilateral restricted diffusion in the hippocampus, which forms part of the Papez circuit. Accordingly, lesions in any location of this circuitry (anterior thalamus, fornices and hippocampus) have consistently showed anterograde amnesia, specifically for episodic memory, which is diagnostic of TGA.