As is widely understood, generalized myoclonus following an anoxic event is considered to have a poor prognosis.


The origin of acute postoperative myoclonus, whether cortical or subcortical, it is not known.



Clinical Features

Age of onset




Differential Diagnosis

Seizure activity

Diagnostic Tests

EEG typically shows a burst suppression pattern, electrographic status epilepticus, periodic epileptiform discharges, and diffuse slower frequencies. The temporal association between these EEG abnormalities and the myoclonus is both variable and imprecise.  Whether the EEG discharges abnormalities are epiphenomena, interictal, or direct ictal discharges responsible for the myoclonus jerk is not known.


There are no published guidelines for the treatment of acute PHM, and reported treatment is mostly anecdotal, so caution and scepticism should be exercised.




Neurophysiological findings in acute PHM.

More than one pattern of electroencephalography was seen in the same patient during the course of myoclonus. Burst suppression was the most common pattern while alpha coma was the least common pattern observed. The highest rate of survival was seen in the diffuse slowing group and the lowest rate was seen in the spike-wave group. Multiple studies were commonly performed in the same patient.