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【专家观点】晕厥的临床评价与处理

MY APPROACH to Evaluating and Treating Syncope
来源:PracticeUpdate 2014-10-09 08:50点击次数:2725发表评论


杰佛逊医学院Peter R Kowey教授 


晕厥是最常见的临床事件,据估计,30%的人会在生命的某个时间点发生晕厥,并在急诊室急诊及紧急护理处理工作中占据了相当的比例。尽管晕厥的发生非常广泛,但诸多内科医师在对拥有晕厥病史的患者进行临床评价时,仍面临巨大挑战。


晕厥的鉴别诊断范围广泛,涉及多器官系统。诊断路径可始于急诊室、神经科或心内科检查。一个明确的事实是,要求如此多的内科医师和其他医护人员看护这些患者,已经导致了大量不合理与非必要护理。毫无疑问,除非诊断明确,否则无法对晕厥患者采用任何治疗方法。


对导致晕厥的严重病情的漏诊会造成深远的不利后果。未经确诊的恶性心律失常或严重的结构性心脏病可直接导致患者死亡。这一事实迫使医护人员开出无意义的检查单,展开无效的治疗。一项例证即是,颈动脉研究与脑部成像被广泛、过度使用,其获益却极低,且很少能够指向正确诊断。


我们如何改善晕厥患者的诊断呢?目前已知、业已证实且被重新确认的是,病史是晕厥患者评价中最重要的要素。这并不是指一些“非正式”的随访,而是需要完整的问答项目,这一环节涉及患者介绍的每一个细节。它应该包括周围环境、前驱与事后症状、预处理因素、持续时间与后遗症。病史的其他要素也可以提供分析的立足点,例如相似症状的家族史,或者突发、意外死亡;社交生活史包括酒精或药物使用;其他疾病状态的完整系统回顾也可以对晕厥原因作出解释或有提示。


让我们看两例人口参数相同的新发晕厥患者病例。第1例为18岁男性患者,有近期病毒感染与腹泻史,其夜间醒来小便期间出现眩晕、恶心,并丧失意识,跌倒后,肩部受到撞击并重新恢复意识,感到虚弱但意识清醒。患者可控制二便,便后回床休息,并于次日清晨告知医师。患者母亲年轻时有类似症状,患者曾被告知长期血压低,要维持良好的水化治疗,特别是在有可能出现低血容量情况下。患者无需其他治疗措施。


第2例患者也是男性,18岁,在无警告条件下、进行跑步场地赛期间意识丧失。患者在跌倒前隐隐有心跳加快、心悸的感觉,但其对该事件的记忆不深。患者醒来后的几分钟感到头晕眼花,无法集中注意力。经过询问,患者记起其男性表兄在18岁时被发现死于游泳池底部。


尽管第1例患者明显与神经心源性(血管迷走性)晕厥有关,第2例患者则明显不是,且情况更危险。剧烈运动期间发生的晕厥必须被视为有潜在致死性,必须评价此类患者是否有结构性心脏病和心律失常综合征。这类特定患者的超声心动图正常,但其ECG则表现为QT间期达520 msec,其在运动期间显著延长,并伴有非持续性室性心动过速的突发状况。该患者接受β受体阻滞剂治疗,但拒绝接受植入式除颤器治疗,不过,患者同意避免竞技性运动。


这些病例说明,良好的病史记录对开展鉴别诊断、进行正确处理和有效治疗很有效力。


Syncope is one of the most common events in clinical medicine. It has been estimated that 30% of people lose consciousness at some point in their lives, and syncope is responsible for a substantial percentage of emergency room and urgent care visits. Despite its ubiquity, syncope is a clinical conundrum and a challenge to the many physicians who are called upon to evaluate patients who have passed out.


The differential diagnosis of syncope is vast and encompasses many organ systems. The path to a diagnosis may start in an emergency room, neurologist’s office, or the cardiologist’s examination room. The very fact that so many physicians and other healthcare providers are called upon to see these patients has led to a good deal of inappropriate and unnecessary care. Without question, the treatment of a syncope patient goes absolutely nowhere until a diagnosis is secured.


There are profound negative consequences to the missed diagnosis of serious conditions that can cause syncope. An undiagnosed malignant arrhythmia or severe structural heart disease can lead directly to a patient’s death. This fact compels care providers to order tests and prescribe treatments that may not make sense. An example is the gross overutilization of carotid studies and brain imaging, which have extremely low yields and rarely lead to a correct diagnosis.


How can we improve the diagnosis of patients with syncope? It has been said, proven, and reconfirmed that the history is the most important element in the evaluation of the syncope patient. This does not refer to a “casual” interview, but rather a thorough question-and-answer session in which every detail of the patient’s presentation is brought forth. It frequently requires information from people who might have witnessed the event. It should include the immediate circumstances, premonitory and post-event symptoms, predisposing factors, duration, and sequelae. Other elements in the history may provide insight as well, such as family history of similar symptoms or sudden, unexpected death; social history including use of alcohol or drugs; and a thorough review of systems for other disease states that could be explanatory or contributory.


Let’s consider 2 patients of identical demographic with a new episode of syncope. An 18-year-old man with a recent viral infection and diarrhea awakened in the middle of the night and while urinating became lightheaded, diaphoretic, and nauseous and lost consciousness. He fell and struck his shoulder and regained consciousness feeling weak but clear-headed. He did not lose control of bowel or bladder, went back to bed, and called his doctor in the morning. His mother had similar symptoms in her youth, and he has been told that he chronically runs a low blood pressure. He was told to maintain good hydration, especially under conditions that might generate hypovolemia. No other treatment was required.


The second patient, also an 18-year-old man, was running a track race when he lost consciousness with no warning. He was vaguely aware of rapid palpitations before he hit the ground, but his memory of the event is poor. When he awakened, he was groggy and poorly focused for several minutes. On questioning, he remembers that he had a male cousin who was found dead at the bottom of a pool at the age of 18.


While the first event is clearly compatible with neurocardiogenic (vasovagal) syncope, the second is not and is clearly more ominous. Syncope during intense effort must be regarded as potentially lethal, and patients with such a presentation must be evaluated for the presence of structural heart disease and arrhythmia syndromes. This particular patient had a normal echocardiogram, but his ECG revealed a QT interval of 520 msec, which prolonged significantly during exercise accompanied by the emergence of unsustained ventricular tachycardia. He was treated with a beta blocker and offered an implanted defibrillator, which he declined; however, he did agree to refrain from competitive sports.


These cases illustrate the power of a good history in the ability to construct a differential diagnosis that led to a correct approach and effective treatment.


Copyright © 2014 Elsevier. All rights reserved.


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学科代码:心血管病学   关键词:晕厥;
来源: PracticeUpdate
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