Abstract
Post-hypoxic myoclonus is a highly concerning phenomenon, which confers a grave but not universally fatal prognosis. We present a case of a 72-year-old woman who developed persistent but fluctuating unilateral facial myoclonus 1-day post cardiothoracic and vascular surgery, that had been complicated by intraoperative haemorrhage and hypoxia. Whilst still intubated and sedated, clinical examination confirmed left lower face twitching that waxed and waned in frequency and amplitude. EEG demonstrated near-continuous, semi-rhythmic 1–2Hz spike-wave and sharp-wave discharges over the right hemisphere maximal centrally, moderate diffuse right hemisphere slowing but only mild background slowing over the left hemisphere. Left temporal leads demonstrated electromyographic artefact time-locked to right sided discharges. MRI-B revealed cortical and subcortical watershed infarcts in the right cerebral hemisphere, and increased signal along the right pericentral cortex, presumed to reflect laminar necrosis. Levetiracetam and subsequently valproate eventually suppressed myoclonus, the patient was able to be extubated after several days and begin communicating after several further days. Asymmetric cerebral hypoperfusion was hypothesised to be related to either underlying vascular disease or surgical redirection of blood flow intraoperatively. This case highlights the variable impact of post hypoxic myoclonus on neuroprognostication. Despite similarity in semiology, there is a spectrum to hypoxic-myoclonus, building on previously recognised entities including Lance-Adams Syndrome and Myoclonic-Status-Epilepticus.1
Reference
Zheng J, Storad Z, Al-Chalabi M, Gharaibeh K, Saleem S, Sheikh, Mahfooz N. Lance-adams syndrome: case series and literature review. Clinical Neurophysiology Practice. 2023;8:187–193. doi: 1016/j.cnp.2023.08.002.
