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Transient global amnesia

Last updated: March 16, 2021

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Transient global amnesia (TGA) is a neurological disorder resulting in acute, transient memory loss. The etiology of this form of amnesia remains unclear, but certain triggers have been identified (e.g., strenuous physical exercise, psychological stress). Affected patients experience sudden memory loss and an impaired ability to retain any new information. Additionally, they may be disoriented to time and place, but retain full knowledge of self-identity. Transient global amnesia resolves after a maximum of 24 hours, after which time the patient spontaneously returns to their normal state of consciousness. The diagnosis is established based on the history of the episode (onset, duration, nature of amnesia). However, an EEG or contrast CT may be performed to rule out transient amnesia caused by other conditions. Transient global amnesia is predominantly associated with a good prognosis and does not indicate an underlying or impending cerebroischemic condition.

  • Peak incidence: 50–80 years (patients are rarely < 40 years) [1]

Epidemiological data refers to the US, unless otherwise specified.

  • Idiopathic
  • Precipitating factors
    • Vigorous physical exercise or exhaustion due to overwork
    • Working bent over (e.g., gardening)
    • Psychological stress
    • Sudden immersion in cold or hot water

References:[2][3][4]

  • Abrupt onset
  • Episodes last between 1–24 h, but never > 24 h (mean duration 6–8 h)
  • Nature of amnesia: anterograde or partial retrograde
  • The patient may appear anxious and distraught, with desperate attempts to orientate themselves.
  • The attack resolves over hours, with older memories returning first, followed by a gradually increasing capacity to retain new information.
  • If the diagnosis is clear, further diagnostic procedures are not necessary.
  • If the diagnosis is uncertain:

References:[2][5]

  • Outpatient management is possible under the supervision of a caregiver.
  • Monitoring for at least 24 h is advisable if an alternative diagnosis is suspected.
  • No medical therapy
  • Resolves spontaneously within 24 h [6]
  • Approximately 3–20% of patients may experience a further episode. [4][7]
  1. Nehring SM, Spurling BC, Kumar A. Transient Global Amnesia. StatPearls. 2021 .
  2. Transient Global Amnesia. http://www.merckmanuals.com/professional/neurologic-disorders/function-and-dysfunction-of-the-cerebral-lobes/transient-global-amnesia. Updated: September 1, 2015. Accessed: March 31, 2017.
  3. Lewis SL. Aetiology of transient global amnesia. The Lancet. 1998; 352 (9125): p.397-399. doi: 10.1016/S0140-6736(98)01442-1 . | Open in Read by QxMD
  4. Miller JW, Petersen RC, Metter EJ, Millikan CH, Yanagihara T.. Transient global amnesia: clinical characteristics and prognosis.. Neurology. 1987; 37 (5): p.733-737.
  5. Nakada T, Kwee IL, Fujii Y, Knight RT. High-field, T2 reversed MRI of the hippocampus in transient global amnesia.. Neurology. 2005; 64 (7): p.1170-1174. doi: 10.1212/01.WNL.0000156158.48587.EA . | Open in Read by QxMD
  6. Hodges JR, Warlow CP. Syndromes of transient amnesia: towards a classification. A study of 153 cases.. J Neurol Neurosurg Psychiatry. 1990; 53 (10): p.834-43. doi: 10.1136/jnnp.53.10.834 . | Open in Read by QxMD
  7. Arena JE, Brown RD, Mandrekar J, Rabinstein AA. Long-Term Outcome in Patients With Transient Global Amnesia: A Population-Based Study.. Mayo Clinic proceedings. 2017; 92 (3): p.399-405. doi: 10.1016/j.mayocp.2016.11.015 . | Open in Read by QxMD