Transient Global Amnesia

History

• 1879 – The term “ictus apoplectiques” was first used by Jean–Alfred Fournier in 1879 to describe amnesic episodes in patients with neurosyphilis.
• 1909 – Earliest clearly documented case resembling modern TGA was reported by Raoul Benon under the term “ictus amnésique.” He described a 66-year-old woman with a 4–5 hour episode of amnesia, repetitive questioning, and a retrograde amnesia of 30 years, without other neurological signs—hallmarks of TGA. Benon distinguished these cases from amnesia due to general paresis.
• 1954, Tormod Hauge reported three cases of transient memory loss following vertebral angiography, now retrospectively recognised as TGA.
• 1956 – American neuroscientist, Morris Bender (1905-1983) described 12 patients with isolated amnestic episodes featuring confusion, repetitive questioning, and no recurrence—attributed to transient cerebral circulatory disturbance. Simultaneously, French neurologist Jean Antoine Courjon (1918-2017) and neuropsychiatrist Jean Alfred Marie Guyotat (1920-2017) described 16 patients with “ictus amnésique”, defined as transient retrograde amnesia without broader cognitive impairment. Unlike Bender’s cohort, six of their cases were recurrent.
• 1958 – The modern term “Transient Global Amnesia” was introduced by Charles Miller Fisher (1913-2012) and Raymond D. Adams (1911–2008)

Epidemiology

• Most cases occur between 50 and 80 years, with mean onset at 60-65 years.

Pathophysiology

• Etiology remains unknown.
• Likely site of disturbance: medial temporal lobe, especially the hippocampus.
• No association with atherosclerotic risk factors.
• No epileptic discharges on EEG.
• Psychogenic stressors may act as triggers.
• Theories include:
  • Migraine variant: vasospasm causing transient ischemia.
  • Venous congestion: Valsalva-associated cerebral venous hypertension.

Clinical Features

• Typically in patients >50 years.
• Abrupt onset and resolution.
• Prominent anterograde amnesia:
  • Repetitive questioning
  • Inability to retain new information
  • Retrograde amnesia may also be present
• Other cognitive functions intact:
  • Normal behaviour, language, and self-awareness
• May perform complex tasks during episode
• Duration: typically 1-12 hours, resolving within 24 hours
• No increased risk of mortality, epilepsy or stroke
• Recurrence rates: 3–25%

Differential Diagnosis

• Seizure/post-ictal states
• Drugs/toxins (e.g. alcohol blackouts)
• Electrolyte disturbances (e.g. hypoglycaemia)
• Wernicke encephalopathy
• Stroke or TIA
• Migraine
• Head trauma
• CNS infection/encephalitis
• Psychogenic amnesia

Investigations

No definitive test. Aim: exclude other causes.

Bloods:

• FBC
• CRP
• U&Es / glucose
• LFTs

ECG:

• Especially to exclude AF

EEG:

• Typically normal

CT/CTA/CT Perfusion:

• To rule out vascular pathology

MRI/MRA:

• May show punctate hippocampal lesions on DWI; these are transient and non-specific

Urine drug screen:

• Consider in younger patients

Management

• Supportive care and reassurance
• No specific therapy required

Disposition

• Admit to Neurology Unit
• Observe until resolution of symptoms

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References

Publications

• Fournier JA. De la syphilis cérébrale In: La syphilis du cerveau. 1879
• Benon R. Les ictus amnésiques dans les démences “organiques”. Annales médico-psychologiques 1909; 67: 207–219.
• Courjon J, Guyotat J. Les ictus amnésiques [Amnesic strokes]. J Med Lyon. 1956 Oct 5;37(882):697-701
• Bender MB. Syndrome of isolated episode of confusion with amnesia. J Hillside Hosp. 1956; 5: 212–5.
• Hauge T. Catheter vertebral angiography. Acta Radiol Suppl. 1954;109:1-219.
• Fisher CM, Adams RD. Transient global amnesia. Transactions of the American Neurological Association. 1958;83:143–6
• Fisher CM, Adams RD. Transient global amnesia. Acta Neurol Scand. 1964;40(Suppl 9):1–81.
• Pearce JM, Bogousslavsky J. ‘Les ictus amnésiques’ and transient global amnesia. Eur Neurol. 2009;62(3):188-92.

FOAMed

• Nickson C. I can see clearly now. LITFL