Transient global amnesia (TGA) is characterized by an abrupt onset of both anterograde and retrograde amnesia, and the patient resembles in many respects someone who has just suffered a traumatic cerebral concussion. • Bartsch et al found that in 7 patients with TGA, 4 had a diffusion abnormality corresponding with a T2 lesion in the CA-1 sector of the hippocampus. In 3 of these patients, MRS revealed a lactate peak.
The incidence has been estimated between 9.6 per 100,000 per annum. A CT scan is often recommended to rule out hemorrhage, infarction, or tumor. Whether, in the absence of other specific indications, this needs to be done immediately is questionable. Similarly, an EEG is often ordered as part of the eventual evaluation. SPECT or PET scanning might also be considered.