To the Editor:

A 68-year-old female patient was referred to our pain clinic for management of zoster pain in her face. Stellate ganglion block (SGB) and infraorbital nerve block improved her pain effectively. At the fifth visit, SGB was performed as before with 4 ml 1.0 % mepivacaine under ultrasound guidance using a 25-gauge, 6-cm needle. After 30 min of uneventful rest in the clinic, she repeatedly asked the same questions and did not recall the conversations even after a few minutes. She was hemodynamically stable. Prompt neurological examination demonstrated that she was alert and oriented without abnormal neurological signs or seizure activities. Long-term memory was intact, her speech was fluent, and there were no signs of local anesthetic toxicity. Blood sugar and electrolytes were unremarkable. No acute abnormalities were found on brain scan (Fig. 1). We diagnosed her symptoms as transient global amnesia (TGA), and she returned to her previous normal neurological state after 20 h.

TGA is a unique syndrome characterized by reversible short-term anterograde amnesia with an unclear etiology in elderly patients [1]. Recently, TGA tends to be considered as a disturbance in the hippocampus-dependent memory [2]. The diagnosis of TGA is clinical and one of exclusion. The memory loss in TGA should be witnessed and without focal neurological symptoms or epileptic features and be resolved within 24 h. This condition should be distinguished from other types of amnesia such as transient epileptic amnesia and transient ischemic attack [2]. Although TGA is self-limiting, it is important for the anesthesiologist to be aware of this unique syndrome and to distinguish it from other neurological complications or local anesthetic toxicity.