Presumptive Acute Post-Hypoxic Myoclonus Following Return of Spontaneous Circulation in a Cat and a Dog

To describe the clinical presentation of presumptive acute post-hypoxic myoclonus in a cat and a dog after cardiopulmonary arrest (CPA). In people, acute post-hypoxic myoclonus is a transient focal, multifocal, or generalized rhythmic myoclonus that results from global hypoxic-ischemic brain injury and may be cortical or subcortical in origin, specifically brainstem-generated. Post-hypoxic myoclonus typically presents within 48 h of CPA while the patient is still comatose. Although this neurologic sign has historically been associated with a poorer prognosis, recent studies suggest that evaluation of its clinical characterization in conjunction with electroencephalographic features should be considered.

We describe the cases of one cat and one dog that suffered CPA, underwent CPR, and experienced return of spontaneous circulation. Both cases developed presumed acute post-hypoxic myoclonus within 24 h of resuscitation, did not respond to antiseizure and sedative drugs, and were subsequently euthanized.

Acute post-hypoxic myoclonus can occur in cats and dogs after CPA and successful resuscitation.