We describe a 42-year-old man with the sudden onset of headache, left-sided neck pain, vomiting, nystagmus, and ataxia 1 h after completing a weightlifting routine. Computed tomography angiography revealed a grade IV left vertebral artery injury with a dissection flap extending distally and resulting in complete occlusion. Subsequent magnetic resonance imaging and angiography demonstrated acute left cerebellar and lateral medullary infarcts, consistent with Wallenberg syndrome. The patient was treated with tissue plasminogen activator, which failed to resolve his symptoms. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians frequently manage patients with acute CVAs. For select patients, the administration of tissue plasminogen activator can improve outcomes. However, the risk of major hemorrhage with this medication is significant. Cervical artery dissection is an important cause of acute stroke in young patients and is often missed on initial presentation. It is imperative for the emergency physician to consider acute cervical artery dissection as a cause of stroke and to be knowledgeable regarding the efficacy of thrombolytic medications for this condition.