疾病的定义与争议

1、疾病的定义与争议内科医生是如何认识“疾病”这个专业术语的？这可难为了临床医生们，因为这种哲学问题可能更应该由中世纪经院哲学家们来回答。但最近医学研究院（IOM）的一篇235页报告，就“系统性劳累不耐受疾病”（SEID）提出了新的见解。这项报告也对患者，医生以及第三支付方有很多具有临床启示。对“疾病”的定义自临床医学建立以来,一直都是争论的焦点。例如，古希腊Knidos学派与Kos学派对疾病的观点就不同。Knidos学派（Aesculapius学院为代表）认为，散在病态实体（如脓肿或肿瘤）是疾病的定义特征，从属于病理学的一般规律。以希波克拉底为代表的偏经验主义Kos学派，强调病人具有特定的痛苦。

2、事实上这两种观点或将疾病视为一种特殊的病理学进程，或将它看成是以患者的自述方式决定其特征的一种特殊的人类体验。19世纪，德国病理学家RudolfVirchow的一项著名声明在医学科学领域引发了一场革命。他提出：“没有广泛疾病，只有局部的疾病。”但是Virchow的同事，LudwigAschoff却不认同，他认为Virchow仅仅是希望将病灶局部化，而不是疾病3。我们确实有理由相信Virchow将疾病概念化为生物体的广义状况，也就是说会随着机体的死亡而消失，不像损伤那样。当代，人们对疾病的定义仍然存在争议。近期，AMA要求科学和公共健康委员会在肥胖的审议中出具一份顾问意见。而委员会面临的一个问题

3、是，“肥胖算是疾病吗？”委员会审慎的回答让我们见识了什么叫语言和谦逊：“因疾病没有统一、明确、权威以及被广泛认可的定义，所以难以最终确定肥胖是否是一种内科疾病。4”不幸的是，在过去的50年间，对Virchow观点的狭义解释（比如近代精神病学家Thomas Szasz）占据了“疾病”讨论的主流。这也使一种观点出现（在我看来是种误解）：只有特定的，可识别的病理生理学或解剖学异常“称为”疾病。然而，这些标准全然不顾古往今来的临床诊断，并且也与许多神经病学、精神病学、疼痛医学的当代诊断不一致。该领域的医生认为许多严重痛苦和失能不能用特定的生化或解剖学发现去解释5。例如：偏头痛，三叉神经痛，甚至是癫痫仍

4、然是基于患者的历史和自述进行临床诊断的。当然，身体检查与影像学研究在排除特定损伤上具有重要作用（例如脑肿瘤）。对绝大多数的精神障碍也是如此。是依据患者的痛苦和失能程度（或悲伤和功能障碍程度）来定义疾病的状态。当然，病理生理相关性、影像学研究、和生物指标可以帮助我们鉴定特定疾病进程的潜在生物学本质，并依此设计合适的治疗方案。但“疾病”作为一种麻烦又影响广泛的人类体验，检测到的这些异常对于疾病的识别既不充分，也不必要。在哈里森内科学中，对疾病的广泛定义如下：临床法将其目标定为：收集以人类为主体的所有疾病的准确数据，也就是说，所有对生命的权利、乐趣，和持续时间造成限制的情况。下划线为新增6。该书作者

5、继续解释医生的“主要、传统的目标是功利主义的预防和治疗疾病，减轻身体或精神的痛苦下划线为新增6”我们再分析IOM报告，该报告将慢性疲劳综合症（也被称为“肌痛性脑脊髓炎”）更名为“系统性劳累不耐受疾病”（SEID），并且对此种疾病的诊断提出基本的临床标准。（我们提到的“Clinical（临床）”源自希腊语klinik“床边”的意思即是床边的诊断）。简要的说，SEID标准必需具有：可影响职业、教育、社会或个人活动前驱疾病水平的实质性下降或损伤；活动后疲倦不能恢复精神的睡眠认知损伤或直立不耐受（或两者都有）注意，SEID标准不需要任何特定的生物学，生化或神经解剖学异常。当然，还需要存在相当程度的悲痛

6、和损伤。必须明确：报告确实发现强有力的证据证明SEID与自然杀伤细胞的功能减弱、Epstein-Barr病毒感染、心肺功能减弱以及神经精神病学异常有关。但这些相关性对SEID诊断来说不是必要条件1。研究人员也在许多精神障碍中发现相似的生物指标和相关异常。例如，异常眼球运动可以准确的区分精神分裂症患者和正常人7。不过，当前的精神分裂症诊断标准跟SEID一样，仍然是基于临床的。IOM报告一出，已经引发了尖锐的批评。某些医生质疑SEID标准缺乏特异性，并且担心存在过度诊断的可能，乃至明目张胆的欺诈行为。这些风险也应该得到重视，但本文作者认为，作为医生，我们的第一责任是识别并缓解人类的病痛和失能，不管

7、我们是否能识别出患者的病理生理学潜因。至于SEID，IOM报告将它明确为：这种状况对患者的社会和职业功能有严重的负面影响1。无疑，我们应该继续研究SEID的潜在生物学机制，就像我们处理精神分裂和非典型性面部疼痛一样。当我们的患者由于体内的原因承受痛苦和失能时，我们有临床和伦理的理由去相信确实存在疾病，并且尽我们所能的去治疗患者。原文：What Is Disease? Implications of Chronic Fatigue SyndromeWhat do physicians intend by the term disease? This may strike many clinici

8、ans as a philosophical question more suited to medieval scholastics than to practicing physicians. But the recent 235-page report on systemic exertion intolerance disease (SEID) from the Institute of Medicine1 (IOM) casts this question in a new light and has many practical implications for patients,

9、 physicians, and third-party payers.The definition of disease has been a matter of contention since the dawn of clinical medicine. For example, the ancient Greek academies of Knidos and Kos had differing views of disease.2 Knidos, the school of Aesculapius, recognized the discrete morbid entity-such

10、 as an abscess or tumor-as the defining feature of disease, subservient to the general rules of pathology. The more empirical school of Kos, associated with Hippocrates, emphasized the sick individual with his particular kind of misery. In effect, these two schools saw disease either as a specific p

11、athological process or as a particular human experience whose character was determined by the patients manner of presentation.In the 19th century, medical science was revolutionized by the German pathologist Rudolf Virchow and his famous pronouncement: Es gibt keine Allgemein krankheiten, es gibt nu

12、r Local krankheiten-There is no general, only local, disease. But Ludwig Aschoff, Virchows colleague, argued that Virchow wished merely to localize lesions, not diseases.3 There are indeed reasons to believe that Virchow conceptualized disease as a generalized condition of the living organism, which

13、, unlike lesions, disappears when the organism dies.To this day, the definition of disease remains controversial. Recently, in its deliberations on obesity, the AMA requested an advisory opinion from its Council on Science and Public Health. The question before the Council was, Is obesity a disease?

14、 The Councils considered response was a lesson in both the limits of language and the merits of humility: Without a single, clear, authoritative, and widely accepted definition of disease, it is difficult to determine conclusively whether or not obesity is a medical disease state.4Unfortunately, in

15、the past 50 years, narrow interpretations of Virchow, such as those of the late psychiatrist Thomas Szasz, have dominated discussions of what constitutes disease.5 This has led to the claim-mistaken, in my view-that only those conditions with specific and identifiable pathophysiology or anatomical a

16、bnormalities count as disease.Yet these criteria fly in the face of medical diagnosis throughout the ages and are not consistent with several modern-day diagnoses in the fields of neurology, psychiatry, and pain medicine. Physicians in these fields recognize that many states of severe suffering and

17、incapacity cannot yet be causally linked with specific biochemical or anatomical findings.5 For example, migraine headache, trigeminal neuralgia, and even epilepsy remain clinical diagnoses-made primarily on the basis of the patients history and subjective reports. (Physical examination and imaging

18、studies, of course, are important in ruling out certain lesions, such as a brain tumor.)This is also true for the vast majority of psychiatric disorders. It is the patients degree of suffering and incapacity-or distress and dysfunction-that defines a state of disease (etymologically, di-sease). Of c

19、ourse, pathophysiologic correlates, imaging studies, and biomarkers can help us understand the underlying biological nature of the specific disease process and devise appropriate treatments. However, such abnormalities are neither necessary nor sufficient for the recognition of disease as a profound

20、 and troubling human experience.5Indeed, in the edition of Harrisons Principles of Internal Medicine that I used when I was a resident, the following breathtakingly broad definition of disease was put forth:The clinical method has as its object the collection of accurate data concerning all the dise

21、ases to which human beings are subject; namely, all conditions that limit life in its powers, enjoyment, and duration italics added.6The editors went on to say that the physicians . . . primary and traditional objectives are utilitarian-the prevention and cure of disease and the relief of suffering,

22、 whether of body or of mind . . . italics added6Now comes the IOM report, which has renamed so-called chronic fatigue syndrome (also called myalgic encephalomyelitis) as systemic exertion intolerance disease (SEID) and proposed essentially clinical criteria for its diagnosis. (Our word clinical is d

23、erived from the Greek klinik bedside-so, diagnosis made at the bedside). In brief, the SEID criteria entail the following:o Substantial reduction or impairment in the ability to engage in pre-illness levels of occupational, educational, social, or personal activitieso Postexertional malaiseo Unrefre

24、shing sleepo Either cognitive impairment or orthostatic intolerance (or both)Note that the SEID criteria do not require the identification of any specific biological, biochemical, or neuroanatomical abnormality. Rather, they entail a substantial degree of distress and impairment. To be clear: the re

25、port did find evidence of a strong association of SEID with diminished natural killer cell function; Epstein-Barr virus infection; decreased cardiopulmonary function; and neuropsychiatric testing abnormalities-but these correlates are not required for diagnosis of SEID.1 Similar biomarkers and assoc

26、iated abnormalities have been found in several psychiatric disorders. For example, abnormal eye movements can distinguish persons with schizophrenia from normal persons with considerable accuracy.7 Nevertheless, current diagnostic criteria for schizophrenia remain clinical, as with SEID.Already, the

27、 IOM report has attracted sharp criticism, with some physicians questioning the lack of specificity in the SEID criteria and worrying about the potential for overdiagnosis and even outright fraud. These risks are not trivial, but I would argue that as physicians, our first duty is the recognition and relief of human suffering and incapacity, whether we can identify the specific pathophysiology underlying the patients condition. With respect to SEID, the IOM report makes it abundantly clear that this condition can have profoundly