Intensivist Sound Critical Care (formerly Sound Physicians), Pennsylvania
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Introduction: Post-anoxic movement disorders are common but typically fall into recognized categories such as myoclonus or dystonia. We report a case of a rare hyperkinetic motor phenotype, characterized by chorea movements, in a comatose survivor of cardiac arrest to highlight a rare presentation that can be mistaken for purposeful movements and affect neuroprognostication.
Description: A 65-year-old female with a history of hypertension and remote renal cell carcinoma presented after a witnessed out-of-hospital cardiac arrest due to ventricular fibrillation. Following resuscitation and targeted temperature management to 37°C, she remained comatose without purposeful motor responses despite intact brainstem reflexes. She developed repetitive, arrhythmic, non-synchronous, that was described by the provider as puppet-like flailing of all four limbs. Routine EEG showed diffuse background slowing but no electrographic seizures corresponding to the movements. Brain MRI demonstrated diffuse cortical and bilateral basal ganglia injury consistent with severe anoxic-ischemic brain injury. The movements persisted despite trials of levetiracetam, valproic acid, and lacosamide. Neurology characterized the movements as a rare choreiform dyskinesia. Given the grave prognosis for a meaningful neurological recovery, the patient was transitioned to comfort care and underwent organ donation after circulatory death.
Discussion: This case describes a unique hyperkinetic movement disorder following severe anoxic brain injury with a "marionette-like" phenomenology not previously characterized in the literature. While diagnosed as a rare chorea, consistent with the basal ganglia injury on MRI, the puppet-like quality also raises the possibility of negative myoclonus, where arrhythmic loss of muscle tone interrupts posturing. The lack of stereotypical movements nor an EEG correlate makes classic post-anoxic myoclonus unlikely. The emergence of such unclassified motor phenomena poses a significant challenge for neuroprognostication and complicates goals-of-care discussions. Further recognition of these atypical motor patterns is needed to refine prognostic frameworks and improve understanding of the full spectrum of post-anoxic motor pathology.
