Lance-Adams syndrome

Marcellino C, Wijdicks EF. Posthypoxic action myoclonus (the Lance Adams syndrome). BMJ Case Rep. 2020 Apr 16;13(4):e234332.

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  • Action myoclonus is exceptionally rare (less than 0.5% in a series of patients who have a cardiac arrest).
  • Myoclonus occurring after hypoxic brain injury from cardiac arrest, characterised by abrupt irregular muscle contractions. (1)
    • Acute: starting within 48 hours after the arrest (when isolated, sometimes terms acute Lance-Adams syndrome). (2)
    • Chronic: Lance-Adams syndrome, which may start from days to weeks after arrest and progressively worsen, with or without other neurological symptoms.
  • Potentially confused with myoclonus status in a comatose patient, yet the examination, imaging, degree of disability and prognosis are very divergent.
  • Typically, no EEG seizure correlates.

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