Convulsive Syncopes in a Patient with Carotid Artery Disease

A 67-year-old male with a history of hypertension, diabetes mellitus, and coronary artery disease suffered from repeated faintings after he got up. His wife reported convulsions of all extremities during fainting and immediate reorientation. On admission neurological examination showed mild dysarthria, while medical examination results were normal. MR imaging revealed a small infarct in the borderzone between the territory of the right middle and posterior cerebral artery and a marked hypoperfusion of both hemispheres as compared to the cerebellum. Ultrasonographic studies of the cerebral arteries showed bilateral, 95% stenosis of the internal carotid arteries, low cerebral blood flow velocities of both middle cerebral arteries, and collateral blood flow from vertebrobasilar arteries. During a head-up tilt test with monitoring of ECG, blood pressure, and cerebral blood flow velocities of both middle cerebral arteries, two convulsive syncopes following a marked decrease in systolic blood pressure and blood flow velocities occurred. Diastolic blood pressure and heart rate remained unchanged. In patients with syncope, standard autonomic tests provide the differential diagnosis of orthostatic circulatory disorders. In our patient with bilateral high-grade carotid artery stenosis the correct diagnosis was made by simultaneous monitoring of the blood flow velocities of both middle cerebral arteries, revealing a deep decrease during head-up tilt. Repeated syncopes display a critically decreased cerebral blood flow during orthostasis due to a severely impaired cerebral autoregulation. Transcranial Doppler sonography may supplement standard autonomic tests in patients with syncope even in the presence of carotid artery disease.