Acute amnesia due to fornix infarction

Abstract

Although the etiology of acute onset amnesia can involve lesion of the fornices, a few cases of pure fornix infarction have been reported. Here we report a 75-year-old right-handed woman with bilateral fornix infarctions. She presented with acute onset global amnesia. Except for amnesia, her neurological evaluation was unremarkable. Brain 3T MRI showed bilateral cytotoxic edema of the anterior columns of the fornix, predominantly on the left side. Her symptoms had improved by 14 days after the onset of amnesia. We speculated that she had severe recent memory impairment due to damage in the Papez circuits. The subcallosal artery (ScA) is thought to feed the columns of the fornix. In this case, infarction of a branch of the ScA might be the cause. Therefore, cases of acute onset amnesia should be evaluated quickly for the possibility of infarction in the Papez circuit.