Limb Shaking as a Manifestation of Low-flow Transient Ischemic Attacks

Abstract

Limb shaking presenting as rhythmic involuntary hyperkinetic movements may represent as severe bilateral occlusive carotid disease. This unusual form of transient ischemic attack is often misdiagnosed as focal motor seizures. However, careful assessment reveals a lack of usual seizure characteristics such as a jacksonian march or facial involvement. The movements also appear to be precipitated by activities that lower blood pressure. We present two cases of patients with severe bilateral carotid stenosis leading to limb-shaking transient ischemic attacks. There was complete stenosis in the internal carotid artery (ICA) contralateral to the jerking limb, combined with significant stenosis in the ipsilateral ICA. Cerebral perfusion on the occluded ICA side was maintained through collateral circulation from the opposite ICA and posterior circulation. When blood pressure was lowered orthostatically or by medication, the resulting cerebral hypoperfusion manifested as limb jerking. Recognition of limb shaking as a rare form of transient ischemic attack and differentiating it from focal motor epilepsy can facilitate early identification of critical carotid stenosis, allowing for appropriate interventions and thus reducing the risk of a disabling stroke. We recommend that clinicians should consider carotid disease in elderly patients presenting with orthostatic or episodic movement disorders.