and 2-8% 2) of patients with DAs, respectively. If these neurologic manifestations occur without pain, although rare, the possibility of DA can be missed without a high index of suspicion 1,7,13) . We managed a patient with a painless DA in which cerebral hemodynamic infarction and thoracic spinal cord ischemia occurred concurrently. Herein, we have focused on the important diagnostic features and therapeutic considerations of DA with a review of the literature.
CASE REPORTA 51-year-old man was referred for further evaluation and treatment of paraplegia and right arm monoparesis. At the referral clinic, he was hypotensive (80/50 mmHg) and diagnosed as septic shock. In the emergency room, the blood pressure was 110/80 mmHg and the pulse was 88 beats/min. The duration of hypotension was less than 24 hours. On physical examination, there were no abnormal findings and he denied any pain in the chest, neck, back, or abdomen. On neurologic examination, the patient was somnolent, but could communicate with the examiners. There was right upper extremity weakness (motor grade II/V) and lower extremity weakness bilaterally (motor grade I/ V). Below the T6 dermatome, anesthesia to pain and hypesthesia to light touch was noted. Below the T11 dermatome, total anesthesia were demonstrated to all types of stimuli. Perianal sensation, and voluntary and involuntary anal sphincter tone could not be elicited. On a plain chest posteroanterior (PA) ra-
INTRODUCTIONAn acute dissecting aneurysm (DA) of the aorta is a rare vascular event with an incidence of 5-30 cases per million people per year 12) . A DA is an uncommon, but potentially catastrophic pathologic change with an extremely high mortality and morbidity. The classic, well-known, typical symptom of DA is severe chest or abdominal pain radiating to the back. This abrupt, lancinating pain can easily make physicians alert and cautious. However, it is important that not all DAs elicit typical pain and the correct diagnosis followed by urgent management cannot always be made. In one report, a DA was missed in 38% of patients on presentation, with 28% of cases diagnosed during autopsy 16) . The frequency of pain-free DAs ranges between 5% and 15% 7,9,13,16) . Such patients with DAs demonstrate signs and symptoms dependent on the involved arterial branches from the ascending to the descending aorta.The neurologic symptoms associated with DA are often dramatic and may completely dominate the clinical features. The frequency of neurologic involvement, including transient deficits, varies between 17% and 40% 1,7,9,13) . Cerebral ischemia and
Department of Neurosurgery, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, KoreaAuthors report a case of a painless acute dissecting aneurysm of the descending aorta in a patient who presented with unexplained hypotension followed by simultaneous paraplegia and right arm monoparesis. To our knowledge, case like this has not been reported previously. Magnetic resonance imaging of the brain and spine revealed h...