Transient global amnesia with unexpected clinical and radiological findings: A case series and systematic review

Background: Transient global amnesia (TGA) represents a benign neurological syndrome of unknown patho-physiology, often accompanied by vanishing hippocampal punctate diffusion-weighted imaging lesions (HPDL). The literature suggests that TGA may present with unusual features. This study analyses atypical clinical and radiological manifestations of patients with TGA and/or HPDL. Methods: We retrospectively reviewed patients with atypical clinical or radiological presentations of TGA and/or HPDL in three neurology centers. We also performed a systematic review of literature using predefined search terms. Results were classified as: A) Atypical clinical manifestations of TGA (such as amnesia with additional manifestations, or only non-amnesic manifestations); B) Atypical radiological manifestations of clinically typical TGA. Results: We identified 83 patients: 18 in our centres (median age 63.5 years, 39% female) and 65 in the literature. In group A, 43 patients presented atypical clinical manifestations such as TGA with added transitory cognitive or sensory-motor deficits, seizures, headaches, but also non-amnesic presentations associated with HPDL and incidental HPDL without symptoms. In group B, 40 patients with typical clinical TGA showed extra-hippocampal punctate diffusion lesions (E-HPDL) which disappeared on follow-up imaging. Using clinical and radiological manifestations, we classified these patients into different categories describing a TGA-PDL spectrum. Conclusions: TGA may have atypical clinical manifestations despite typical neuroimaging and patients with typical TGA may show vanishing extra-hippocampal punctate diffusion lesions. TGA, related clinical manifes-tations, and vanishing punctate diffusion lesions should be considered part of a larger TGA-PDL spectrum, allowing for better diagnosis of typical and atypical cases and stimulating further studies.

Automated summary

This study analyzed the atypical clinical and radiological manifestations of patients with transient global amnesia (TGA) and/or hippocampal punctate diffusion-weighted imaging lesions (HPDL). The results showed that TGA may have atypical clinical manifestations, and patients with typical TGA may show disappearing extra-hippocampal punctate diffusion lesions. These findings contribute to better diagnosis of typical and atypical cases and stimulate further research.