General description

Transient global amnesia is an acute onset condition characterized by profound anterograde amnesia and varying degrees of retrograde amnesia, lasting typically 1–8 hours but sometimes ranging from 30 minutes to 24 hours. It is a rare disorder, affecting 5–6 per 100,000 people annually, and resolves without leaving residual neurological deficits. The cause remains uncertain, but possible mechanisms include ischemia, migraines, seizures, venous congestion, or psychological stress.

Transient global amnesia often presents with sudden memory loss, where patients exhibit disorientation in time and place but maintain recognition of people. They may repeatedly ask questions such as, "Where am I?" or "What is happening?" despite intact language, attention, visuospatial skills, and social behavior. Mild accompanying symptoms like headache, nausea, or dizziness may occur in the acute phase.

Radiographic features

MRI shows punctate or patchy DWI hyperintensity in the hippocampus, typically lasting 7–10 days after onset. ADC values generally decrease during this period and return to normal after 10 days.