Deterioration of a neurologic deficit was observed in a 47-year-old patient with high-grade bilateral internal carotid artery stenoses. She presented monoplegia of the right leg with progression to triplegia (bicrural and left arm) following antihypertensive treatment of a suspected "hypertensive crisis". Triplegia is a very rare syndrome and highly suggestive of bilateral pathology of the carotid arteries. Antihypertensive treatment is contraindicated because sufficient blood pressure is needed for adequate perfusion of the brain, especially in the border zones between the great cerebral arteries. Allowing a high blood pressure and low head positioning led to slow recovery from the neurologic deficit, which continued after bilateral carotid endarterectomy. The patient became ambulatory without assistance and with minimal residual paraspasticity. Triplegia and other patterns of motor deficit in cerebrovascular disorders are discussed and the clinical picture of hypertensive encephalopathy is reviewed.