transient global amnesia
Also written as: TGA — transient global amnesia
Sudden onset of severe anterograde amnesia lasting hours, with preserved consciousness and personal identity. A benign condition of unclear etiology requiring differentiation from stroke.
Full Definition
Transient global amnesia (TGA) is a distinctive neurological syndrome characterized by the sudden onset of severe anterograde amnesia (inability to form new memories) that typically lasts 1-24 hours before resolving completely. During episodes, patients remain alert and maintain their personal identity and well-learned skills but cannot remember recent events or form new memories. They often repeatedly ask the same questions about current circumstances or time. The condition predominantly affects middle-aged and older adults and is generally considered benign with an excellent prognosis. The exact cause remains unclear, though proposed mechanisms include transient ischemia, migraine-related phenomena, or venous congestion affecting hippocampal structures. Diagnosis requires careful exclusion of other causes of acute memory loss, including stroke, seizures, or toxic metabolic conditions. Recurrence is uncommon, occurring in less than 10% of cases.
Usage
Usage note: TGA acronym commonly used. Emphasize transient nature and complete recovery in documentation.
In Context
- "The patient's transient global amnesia resolved completely within 18 hours with no residual deficits." — Emergency department discharge summary
- "Neuroimaging was normal in this case of typical transient global amnesia." — Neurology consultation note