Transient Global Amnesia
Introduction[edit | edit source]
Transient global amnesia (TGA) is a clinical syndrome, usually occurring in those over 50, with as yet unknown etiology. TGA is transient in nature, with an acute onset and resolves within a twenty four hours. It is often preceded by such events as very strenuous, migraines, high-stress, or sexual intercourse.
Pathophysiology[edit | edit source]
TGAs are thought to begin in the hippocampus. The region of the hippocampus is an area were blood drains in the brain and is vulnerable to impact from various metabolic stresses. When changes are seen here they are found on MRI around 2 days post event, after symptoms have resolved. 
Risk Factors[edit | edit source]
The clearest risk factor is age, with people over 50 have a greater risk. Male and female have the same risk.
- Research shows that approximately 12% of clients may experience recurrence, this risk further increasing if there is a history of migraine, depression, or sexual intercourse before the TGA episode.
- Those with a history migraines have x 2 the risk, and those with depression are at x 4 the risk of having a TGA episode.
- Recurrence rates are not known but studies suggest it is between 2.9% and 22.8%.
- History of a stroke or epilepsy are not risk factors.
Presentation[edit | edit source]
TGA presents neurologically dramatically and may cause great concern to both patient and clinician. Anterograde and partial retrograde amnesia with a duration of less than 24 hours without no lasting symptoms are the hallmarks of TGA. Semantic memory is less affected than episodic, and most cases memories resolve within a few hours. Usually the person will be unable to create new memories, and repetitively asks questions, usually the same question like "What am I doing here?" or "How did we get here?".
Differential Diagnosis[edit | edit source]
Most important to rule out stroke. Other diagnoses include:
- transient epileptic amnesia
- psychogenic amnesia
- drug-related amnesia
- post-traumatic amnesia
Treatment[edit | edit source]
No treatment is undertaken, and the condition completely resolves in 24 hours.
References[edit | edit source]
- Nehring SM, Spurling BC, Kumar A. Transient global amnesia. InStatPearls [Internet] 2022 Jul 31. StatPearls Publishing.Available:https://www.ncbi.nlm.nih.gov/books/NBK442001/ (accessed 31.3.2023)
- Enzinger C, Thimary F, Kapeller P, Ropele S, Schmidt R, Ebner F, Fazekas F. Transient global amnesia: diffusion-weighted imaging lesions and cerebrovascular disease. Stroke. 2008 Aug 1;39(8):2219-25.Available:https://www.ahajournals.org/doi/10.1161/STROKEAHA.107.508655 (accessed 31.3.2023)
- Hernández MA, Arena JE, Alessandro L, Allegri RF, Calandri IL. Transient Global Amnesia Recurrence: Prevalence and Risk Factor Meta-analysis. Neurology: Clinical Practice. 2022 Aug 1;12(4):e35-48.Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9647817/(accessed 31.3.2023)
- Miller TD, Butler CR. Acute-onset amnesia: transient global amnesia and other causes. Practical Neurology. 2022 Jun 1;22(3):201-8.Available:https://pn.bmj.com/content/22/3/201 (accessed 31.3.2023)
- Radiopedia Transient Global Amnesia Available:https://radiopaedia.org/articles/transient-global-amnesia (accessed 31.34.2023)