Transient Global Amnesia with Reversible White Matter Lesions: A Variant of Posterior Reversible Encephalopathy Syndrome?

Abstract

Transient global amnesia (TGA) is a self-limited disease characterized by isolated amnesia, which resolves within 24 h. In contrast, posterior reversible encephalopathy syndrome (PRES) is a potentially life-threatening disease that usually presents with seizures, altered mental status, headache, and visual disturbances. It is characterized by reversible vasogenic edema that predominantly involves the parieto-occipital subcortical white matter as shown by neuroimaging studies. To date, there have been no reported cases of PRES with a clinical course resembling TGA. Here we report the case of a 58-year-old woman who presented with isolated amnesia and headache. On admission, her blood pressure was 187/100 mmHg. She had complete anterograde amnesia and slight retrograde amnesia without other neurological findings. After the treatment of her hypertension, the amnesia resolved within 24 h. Although the initial magnetic resonance image (MRI) was almost normal, the fluid attenuation inversion recovery (FLAIR) images of the MRI on the next day revealed several small foci of high intensity areas in the fronto-parieto-occipital subcortical white matter, presumed to be vasogenic edema in PRES. The lesions disappeared one month later. This case suggests that PRES can mimic the clinical course of TGA. PRES should be considered in the differential diagnosis for TGA.

Prevalence of Mimics and Severe Comorbidity in Patients with Clinically Suspected Transient Global Amnesia

“…There are also occasional reports of single patients with posterior reversible encephalopathy syndrome (PRES) who suffered TGA-like episodes, which could only be detected by MRI [19]; the pathophysiology of these cases remains unclear like in some of our patients, where it was not always possible to decide, whether they had a definite TGA (with concurrent features) or a different pathology, mimicking the syndrome. Not least because of that we summarized these patients as “complicated TGA/mimic” because for a personalized therapy, it is more important to assess all (treatable) features of the individual’s state than to make a (academically correct) definite distinction, which will always be artificial to some extent, as long as the exact pathomechanism of TGA is not completely understood.…”

A global amnesia associated with the specific variant of posterior reversible encephalopathy syndrome (PRES) that developed due to severe preeclampsia and malignant hypertension

“…Certain conditions such as malignant hypertension and eclampsia, among others, are reported as the potential causes of PRES, while the pathophysiological mechanisms implicated are a breakthrough of vascular autoregulation and endothelial dysfunction [ 4 ]. Only a few sporadic reports in the literature exist that bring amnesia or amnesia-like symptomatology into association with PRES [ 5 , 6 ]. However, a dramatic memory deficit that included both anterograde and retrograde memory processing, as implicated in our case, has not been previously elaborated.…”