Transient Global Amnesia (TGA)

Abstract

Patients with transient global amnesia (TGA) are typically middle-aged or elderly who are usually brought to the emergency department by a relative describing the patient as being “confused.” There are no focal neurological deficits, and cognitive as well as language functions are intact. However, there is a profound anterograde more than retrograde amnesia for the preceding several hours or a day. Patients are usually quite agitated and may repeat the same question (previously answered) over and over, such as “What am I doing here? Where am I?” Over time, the anterograde amnesia subsides and resolves completely. TGA may often appear in the setting of an emotional or physical stress.

In the initial evaluation, the patient is typically clinically stable. Providing reorientation and reassurance is helpful. Apart from antecedent physical and emotional precipitants, rule out benzodiazepine use which may also have a similar amnestic sequelae. The neurological examination and basic lab work with ECG should reveal no abnormalities.

Where indicated, testing may be needed to exclude other neurological conditions which can present with a similar type of memory disturbance. Electroencephalogram (EEG) can help to assess for any interictal epileptic discharges in cases of epilepsy. Head CT scan or MRI is useful in determining mass lesions or possible vascular causes such as stroke.

The exact pathophysiology of TGA still remains unclear. As such, both epileptic and vascular mechanisms have been proposed but have not been proven. The condition is self-limiting and there is no specific treatment. The prognosis is usually good. The rate of recurrence is low, generally occurring in about 8 % of patients.