Transient global amnesia caused by cryptogenic ischemic stroke

Abstract

Background: TGA (transient global amnesia) is a syndrome with anterograde memory loss. Several hypotheses have been proposed for the TGA. However, precise mechanism is not well known. We have experienced a TGA patient with two lesions in different arterial territories presumed to be caused by embolic cause. Case description: A 54-year-old man who had no disease other than hypertension visited the emergency room. The patient repeated the same question, with no other neurologic deficits. Brain magnetic resonance imaging revealed an acute lesion in the right frontal lobe and hippocampus. We performed a microbubble test using transcranial Doppler to discriminate embolic causes and identified right to left shunts, which are thought to be patent foramen ovale. The patient was on antiplatelet and discharged without recurrence. Conclusion: There is still insufficient clinical evidence for the hypothesis that TGA is caused by ischemic etiology. When TGA occurs, stroke risk factors are not usually assessed. However, studies have often reported that ischemic causes are associated with TGA like our case. Therefore, it is worthwhile to evaluate the potential source of stroke in TGA patients. According to the test results, antithrombotic medications may be required for secondary prevention of ischemic events.

Keywords

• Transient global amnesia
• Cryptogenic
• Ischemic stroke
• Patent foramen ovale