II. Definitions

  1. Transient Global Amnesia
    1. Transient inability to form new memories (Anterograde Amnesia) in episode lasting minutes to hours

III. Epidemiology

  1. Incidence 5-10 per 100,000 per year (23 to 32 per 100,000 per year in age over 50 years)
  2. Age: Over age 50 years (typical age range 50 to 80 years)

IV. Pathophysiology

  1. Dysfunction of bilateral medial Temporal Lobes, and Hippocampus
    1. MRI Brain DWI has shown bright punctate foci in Hippocampus of TGA patients
    2. Jain (2018) Indian J Radiol Imaging 28(1): 6-9 PMID: 29692518 [PubMed]
  2. Associations with Migraine Headache, Temporal Lobe ischemia or partial complex Seizures have been postulated
  3. Venous congestion and venous reflux is also postulated as cause
    1. May explain why some TGA episodes are preceded by straining or Valsalva Maneuver
    2. Lewis (1998) Lancet 352(9125):397-9 [PubMed]

V. Symptoms

  1. Previously well person becomes confused and amnestic
    1. Transient inability to form new memories (esp. immediate and recent)
    2. Episode lasts for minutes to hours (typically up to 12-24 hours)
  2. Spontaneous onset is typical, however is associated with triggers in some cases
    1. Emotional stress
    2. Physical exertion
    3. Sexual intercourse
    4. Water immersion

VI. Exam

  1. Normal Level of Consciousness and orientation
  2. Impaired ability to form new memories
  3. Other intellectual tasks preserved
  4. No other neurologic deficits

VII. Diagnosis

  1. Witnessed abrupt onset of Anterograde Amnesia (mild Retrograde Amnesia may also be present) AND
  2. Otherwise normal other cognition including normal level of conciousness, orientation and attention AND
  3. No history of Head Injury or Seizures AND
  4. Non-focal Neurologic Exam during and after the episode AND
  5. Personal identity intact (contrast with Dissociative Amnesia or Fugue State)

IX. Evaluation

  1. Exclude Cerebrovascular Accident with neuroimaging
  2. Consider EEG
  3. Observe (typically in hospital until resolution)

X. Prognosis

  1. Complete recovery is typical
  2. Rarely recurrs

XI. Resources

  1. Nehring, Spurling and Kumar (2020) Transient Global Amnesia, Stat Pearls (accessed 6/1/2021)

XII. References

  1. Brown and Hachinski in Wilson et. al. (1991) Harrison's Internal Medicine, Twelfth Edition, McGraw-Hill, St. Louis, p.188-9
  2. Pensa and Swaminathan in Herbert (2021) EM:Rap 21(6): 1-2

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Related Studies

Ontology: Amnesia, Transient Global (C0338591)

Definition (NCI) A condition characterized by sudden, temporary, usually short-lived memory loss, not associated with a neurologic disorder. Affected individuals lose memory function for recent events and have a decreased ability to retain new information. It is usually a solitary event.
Definition (MSH) A syndrome characterized by a transient loss of the ability to form new memories. It primarily occurs in middle aged or elderly individuals, and episodes may last from minutes to hours. During the period of amnesia, immediate and recent memory abilities are impaired, but the level of consciousness and ability to perform other intellectual tasks are preserved. The condition is related to bilateral dysfunction of the medial portions of each TEMPORAL LOBE. Complete recovery normally occurs, and recurrences are unusual. (From Adams et al., Principles of Neurology, 6th ed, pp429-30)
Concepts Mental or Behavioral Dysfunction (T048)
MSH D020236
ICD9 437.7
ICD10 G45.4
SnomedCT 366963000, 195202003, 367187006, 230736007
Swedish Total minnesförlust, övergående
Czech amnézie přechodná celková, Globální tranzitorní amnézie, tranzitorní globální amnézie
Finnish Ohimenevä täydellinen muistinmenetys
Italian AGT (Amnesia globale transitoria ), Amnesia totale transitoria, Amnesia globale transitoria
English transient global amnesia (diagnosis), transient global amnesia, TGA (Transient Global Amnesia), Amnesia, Transient Global, Global Amnesia, Transient, Transient Global Amnesia, Amnesia, Transient Global [Disease/Finding], global transient amnesia, TGAs (Transient Global Amnesia), Transient global amnesia (disorder), TGA - Transient global amnesia, Transient global amnesia, Transient global amnesia (finding), amnesia; transient global, transient global; amnesia
German Transiente globale Amnesie [amnestische Episode], transitorisch-globale Amnesie, Amnesie, transitorisch-globale, Transitorisch-globale Amnesie
Korean 일과성 구상 기억상실증
Spanish Amnesia global transitoria, amnesia total transitoria (hallazgo), amnesia total transitoria, Amnesia Global Transitoria, Amnesia Transitoria Global
Portuguese Amnésia global transitória, Amnésia Global Transitória
Dutch voorbijgaande globale amnesie, amnesie; transient global, transient global; amnesie, Transient global amnesia, Amnesie, voorbijgaande globale, Globale amnesie, voorbijgaande, Voorbijgaande globale amnesie
Japanese イッカセイゼンケンボウ, 全健忘症-一過性, 一過性全健忘, 一過性全健忘症, 全健忘-一過性
Polish Niepamięć przejściowa, Utrata pamięci przejściowa całkowita, Amnezja przejściowa całkowita
Hungarian Átmeneti globális amnesia
Norwegian Forbigående hukommelsestap, Amnesi, transitorisk, Forbigående totalt hukommelsestap, Transitorisk global amnesi
French Amnésie globale transitoire, Ictus amnésique, Ictus amnésique (IA)