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The amnesias are disorders involving partial or total inability to recall past experiences. Causes include psychogenic (conversion disorder, fugue states, factitious, severe anxiety and stress, major depression etc.), Wernicke–Korsakoff syndrome (alcohol), post-trauma, transient organic states (CVA, epilepsy, hypoxia, cerebral infection, drugs, etc.), cerebral tumour, SAH, various drugs (alcohol, cannabis, anti-epileptics, digoxin, methamphetamines, etc.) and transient global amnesia.
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TRANSIENT GLOBAL AMNESIA
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Benign condition of middle-aged and elderly
Acute-onset profound amnesia; also anterograde and retrograde amnesia
State of bewilderment (e.g. ‘Where am I?’); repetitive queries
Self-limited—usu. 4–8 (up to 24) h
Complete resolution
Usually single episode (20% recurrence)
May be precipitating event (e.g. stress)
No other neurological symptoms or signs
Able to perform complex motor skills (e.g. driving)
Good prognosis: complete resolution
Investigations generally unhelpful; witness of event essential for diagnosis
No active treatment recommended: reassurance and explanation