Kapoor W N
Department of Medicine, University of Pittsburgh, Pennsylvania.
Am J Med. 1991 Jan;90(1):91-106. doi: 10.1016/0002-9343(91)90511-u.
Syncope is a common medical problem and is caused by a wide variety of diseases ranging from physiologic derangements with few consequences to conditions that may be immediately life-threatening. Because of the large differential diagnosis, many diagnostic tests are available for its evaluation. However, a cause of syncope is not established in 38% to 47% of patients despite these tests. In those patients in whom a diagnosis can be assigned, the history and physical examination identify a potential cause in 49% to 85%. Furthermore, in 8% of additional patients, history and physical examination are suggestive of causes that need confirmation by specific tests. Routine blood tests rarely yield diagnostically helpful information. In those patients in whom a potential cause for syncope is identified, arrhythmias are diagnosed by electrocardiogram in 2% to 11% of patients, cardiac monitoring in 3% to 27% (telemetry or Holter), stress test in less than 1%, carotid massage in less than 1%, and electrophysiologic studies in less than 3%. Diagnosis of arrhythmias as a cause of syncope is problematic because symptomatic correlation during electrocardiographic monitoring is rarely found (approximately 4%), and as a result, there is no uniform agreement on diagnostic criteria for abnormalities. Similar problems exist in the use of electrophysiologic studies. Upright tilt testing and psychiatric examination may be useful in evaluation of recurrent syncope of unknown cause in patients without organic heart disease. Based on the results of recent studies, strategies for evaluation of patients with syncope are possible that utilize selective and goal-directed diagnostic testing.
晕厥是一种常见的医学问题，由各种各样的疾病引起，从几乎没有后果的生理紊乱到可能立即危及生命的情况。由于鉴别诊断范围广，有许多诊断测试可用于评估晕厥。然而，尽管进行了这些测试，仍有38%至47%的患者无法确定晕厥原因。在那些能够明确诊断的患者中，病史和体格检查可在49%至85%的患者中确定潜在病因。此外，在另外8%的患者中，病史和体格检查提示可能病因，需要通过特定检查加以证实。常规血液检查很少能提供有助于诊断的信息。在那些确定了晕厥潜在病因的患者中，通过心电图诊断心律失常的患者占2%至11%，通过心脏监测（遥测或动态心电图）诊断的占3%至27%，通过负荷试验诊断的不到1%，通过颈动脉按摩诊断的不到1%，通过电生理检查诊断的不到3%。将心律失常诊断为晕厥病因存在问题，因为在心电图监测期间很少发现症状相关性（约4%），因此，对于异常的诊断标准没有统一的共识。电生理检查的应用也存在类似问题。直立倾斜试验和精神科检查可能有助于评估无器质性心脏病患者不明原因的反复晕厥。根据最近的研究结果，可以采用选择性和目标导向的诊断测试来评估晕厥患者。
