摘要Myelopathy is a common etiology of acute bilateral limb weakness.While painless acute aortic dissection(AAD)is the most common catastrophic event that can mimic myelopathic manifestations of acute bilat-eral limb weakness,it is often easily ignoredWe describe a case of painless AAD in a 70-year-old man with a histo-ry of hypertension manifesting as acute myelopathy(bi-lateral limb weakness and loss of all types of sensation)with increased levels of serum myoglobin and D-dimer.Magnetic resonance imaging of the spinal cord revealed a normal thoracic and lumbar spinal cord but a dissection of the thoracic aorta.Computed tomography angiography of the chest and abdominal aorta showed a Stanford type B dissection extending throughout the thoracic aorta and into the abdominal aorta hypomere.The patient died be-cause of a sudden drop in blood pressure during transfer to vascular surgery.The clinical presentation of painless AAD mimics myelopathies.Aortic dissection should be considered in patients presenting with acute bilateral limb weakness.Physical examination of the skin temperature,dorsalis pedis artery,serum D-dimer,and myocardial markers can provide diagnostic clues.