Bradley John G, Davis Kathy A
Department of Family and Community Medicine, Southern Illinois University School of Medicine, Decatur, Illinois 62526, USA.
Am Fam Physician. 2003 Dec 15;68(12):2393-8.
Orthostatic hypotension is a physical finding defined by the American Autonomic Society and the American Academy of Neurology as a systolic blood pressure decrease of at least 20 mm Hg or a diastolic blood pressure decrease of at least 10 mm Hg within three minutes of standing. The condition, which may be symptomatic or asymptomatic, is encountered commonly in family medicine. In healthy persons, muscle contraction increases venous return of blood to the heart through one-way valves that prevent blood from pooling in dependent parts of the body. The autonomic nervous system responds to changes in position by constricting veins and arteries and increasing heart rate and cardiac contractility. When these mechanisms are faulty or if the patient is hypovolemic, orthostatic hypotension may occur. In persons with orthostatic hypotension, gravitational opposition to venous return causes a decrease in blood pressure and threatens cerebral ischemia. Several potential causes of orthostatic hypotension include medications; non-neurogenic causes such as impaired venous return, hypovolemia, and cardiac insufficiency; and neurogenic causes such as multisystem atrophy and diabetic neuropathy. Treatment generally is aimed at the underlying cause, and a variety of pharmacologic or nonpharmacologic treatments may relieve symptoms.
直立性低血压是一种体征，美国自主神经学会和美国神经病学学会将其定义为站立三分钟内收缩压至少下降20毫米汞柱或舒张压至少下降10毫米汞柱。这种情况可能有症状，也可能无症状，在家庭医学中很常见。在健康人中，肌肉收缩通过防止血液在身体下垂部位积聚的单向瓣膜增加静脉血回流到心脏。自主神经系统通过收缩静脉和动脉以及增加心率和心脏收缩力来应对体位变化。当这些机制出现故障或患者血容量不足时，可能会发生直立性低血压。在直立性低血压患者中，重力对静脉回流的阻碍会导致血压下降，并威胁到脑缺血。直立性低血压的几个潜在原因包括药物；非神经源性原因，如静脉回流受损、血容量不足和心脏功能不全；以及神经源性原因，如多系统萎缩和糖尿病性神经病变。治疗通常针对潜在病因，多种药物或非药物治疗可能会缓解症状。
