疾病的定义
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疾病得定义与争议
内科医生就是如何认识“疾病”这个专业术语得?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)得一篇235页报告,就“系统性劳累不耐受疾病"(SEID)提出了新得见解。
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”得定义自临床医学建立以来,一直都就是争论得焦点。
例如,古希腊Knidos学派与Kos学派对疾病得观点就不同。
Knidos学派(Aesculapius学院为代表)认为,散在病态实体(如脓肿或肿瘤)就是疾病得定义特征,从属于病理学得一般规律。
以希波克拉底为代表得偏经验主义Kos学派,强调病人具有特定得痛苦。
事实上这两种观点或将疾病视为一种特殊得病理学进程,或将它瞧成就是以患者得自述方式决定其特征得一种特殊得人类体验。
19世纪,德国病理学家RudolfVirchow得一项著名声明在医学科学领域引发了一场革命。
她提出:“没有广泛疾病,只有局部得疾病。
”但就是Virchow得同事,LudwigAschoff 却不认同,她认为Virchow仅仅就是希望将病灶局部化,而不就是疾病[3]。
我们确实有理由相信Virchow将疾病概念化为生物体得广义状况,也就就是说会随着机体得死亡而消失,不像损伤那样、
当代,人们对疾病得定义仍然存在争议。
近期,AMA要求科学与公共健康委员会在肥胖得审议中出具一份顾问意见、而委员会面临得一个问题就是,“肥胖算就是疾病不?”委员会审慎得回答让我们见识了什么叫语言与谦逊:“因疾病没有统一、明确、权威以及被广泛认可得定义,所以难以最终确定肥胖就是否就是一种内科疾病。
[4]”
不幸得就是,在过去得50年间,对Virchow观点得狭义解释(比如近代精神病学家ThomasSzasz)占据了“疾病”讨论得主流。
这也使一种观点出现(在我瞧来就是种误解):只有特定得,可识别得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得临床诊断,并且也与许多神经病学、精神病学、疼痛医学得当代诊断不一致。
该领域得医生认为许多严重痛苦与失能不能用特定得生化或解剖学发现去解释[5]。
例如:偏头痛,三叉神经痛,甚至就是癫痫仍然就是基于患者得历史与自述进行临床诊断得。
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)。
对绝大多数得精神障碍也就是如此。
就是依据患者得痛苦与失能程度(或悲伤与功能障碍程度)来定义疾病得状态、当然,病理生理相关性、影像学研究、与生物指标可以帮助我们鉴定特定疾病进程得潜在生物学本质,并依此设计合适得治疗方案。
但“疾病”作为一种麻烦又影响广泛得人类体验,检测到得这些异常对于疾病得识别既不充分,也不必要。
在《哈里森内科学》中,对疾病得广泛定义如下:
临床法将其目标定为:收集以人类为主体得所有疾病得准确数据,也就就是说,所有对生命得权利、乐趣,与持续时间造成限制得情况。
[下划线为新增][6]、
该书作者继续解释医生得“主要、传统得目标就是功利主义得——预防与治疗疾病,减轻身体或精神得痛苦……[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),并且对此种疾病得诊断提出基本得临床标准、(我们提到得“C linical(临床)”源自希腊语klinikē“床边”得意思—-即就是床边得诊断)。
简要得说,SE ID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得实质性下降或损伤;
●活动后疲倦
●不能恢复精神得睡眠
●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得生物学,生化或神经解剖学异常、当然,还需要存在相当程度得悲痛与损伤。
必须明确:报告确实发现强有力得证据证明SEID与自然杀伤细胞得功能减弱、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诊断来说不就是必要条件[1]。
研究人员也在许多精神障碍中发现相似得生物指标与相关异常、例如,异常眼球运动可以准确得区分精神分裂症患者与正常人[7]。
不过,当前得精神分裂症诊断标准跟SEID一样,仍然就是基于临床得。
IOM报告一出,已经引发了尖锐得批评。
某些医生质疑SEID标准缺乏特异性,并且担心存在过度诊断得可能,乃至明目张胆得欺诈行为、这些风险也应该得到重视,但本文作者认为,作为医生,我们得第一责任就是识别并缓解人类得病痛与失能,不管我们就是否能识别出患者得病理生理学潜因。
至于SEID,IOM报告将它明确为:这种状况对患者得社会与职业功能有严重得负面影响[1]、
无疑,我们应该继续研究SEID得潜在生物学机制,就像我们处理精神分裂与非典型性面部疼痛一样、当我们得患者由于体内得原因承受痛苦与失能时,我们有临床与伦理得理由去相信确实存在疾病,并且尽我们所能得去治疗患者。
原文:
What Is "Disease”? Implications ofChronic F atigue Syndrome
What do physicians intend bytheterm”disease"?This may strike manycliniciansas a philosophical questionmore suited to medieva lscholasticsthan to practicingphysicians、But the recent235—page rep ort on ”systemic exertion intolerancedisease" (SEID) fromthe Institu te of Medicine1(IOM) caststhisquestion in a new lightand has many practical implications for patients, physicians, and third-party payers、The definition of”disease"has been a matterof contentionsince the dawnof clinicalmedicine.For example, theancient Greekacademies of Knidosand Koshad differing views ofdisease。
2 Knidos, the school ofAesculapius,recognizedthediscrete morbid entity—such
as an abscess ortumor-asthe defining featureofdisease, subser vient to the generalrulesof pathology、The more empirical schoolo fKos,associatedwithHippocrates, emphasized the sickindividual with his particularkind of misery、In effect, these two schools sawdisease eitheras aspecificpathologicalprocess or as a particular human experience whose character was determined by thepatient’s manner of presentation、
Inthe19th century, medical science was revolutionizedby the German pathologist RudolfVirchowand hisfamous pronouncement: Es gibtkeine A llgemeinkrankheiten,es gibt nur Local krankheiten—"Thereis no gene ral, only local,disease。
” But Ludwig Aschoff, Virchow’s colleague, arg ued thatVirchowwished merely to localize lesions, not diseases、3 Thereare indeed reasons to believe that Virchow conceptualized disease as a generalizedconditionofthe living organism, which, unlike les ions, disappears whenthe organism dies。
To this day, the definition ofdisease remains controversial. Recently, in its deliberations on obesity,theAMA requestedan advisory opinion from its Councilon Science and PublicHealth. The question before the Council was, "Isobesity adisease?” TheCouncil’sconsideredresponse was alesson in boththelimitsof language and the meritsof humility: "Withoutasingle, clear, authoritative, and widelyaccepted definition ofdisease, it isdifficult to determine conclusively whe theror not obesityis amedical diseasestate."4
Unfortunately, inthe past50 years, narrow interpretations of Virchow, s uch as thoseof the latepsychiatrist Thomas Szasz, havedominated discussions of what constitutes”disease。
"5 Thishas led tothe claim—mistaken, inmy view-thatonly those conditions with specificand identifia ble pathophysiologyor anatomicalabnormalities”count"as disease、
Yet these criteria fly in the face ofmedical diagnosis throughoutthe agesand are not consistentwith several modern-day diagnoses inthefieldsof neurology, psychiatry, and painmedicine、Physiciansin these fields recognizethat many states of severesuffering and inca pacity cannot yet becausally linkedwith specific biochemical or anatomicalfindings。
5Forexample, migraine headache, trigeminal ne uralgia, and evenepilepsyremainclinicaldiagnoses-made primarilyon the basisof the patient’shistory andsubjective reports、(Physic al examination and imaging studies, ofcourse, are important in ruling out certainlesions, such as a brain tumor。
)
Thisis also true for thevast majority of psychiatricdisorders、Itis the p atient's degreeof suffering and incapacity—or distress anddysfunction-that defines astateof disease (etymologically,di—sease)、Of course,pathophysiologic correlates, imaging studies, and biomarkers can helpus understand theunderlying biological nature of the specificdisea
se processanddevise appropriatetreatments. However, such a bnormalitiesare neither necessary nor sufficient for therecognition of"disease"as aprofoundand troubling humanexperience。
5
Indeed, in the editionofHarrison's Principlesof Internal Medicine that I used when I was a resident,the following breathtakingly bro ad definition of diseasewas putforth:
The clinicalmethod has as its object thecollection of accurate data concerning all the diseases towhich humanbeings are subject; namely, allconditions thatlimit life in its powers, enjoyment, andduration[italics added]。
6
Theeditors went onto say that the physician's”。
、。
primaryand traditional objectives are utilitarian-the prevention and cure of disease and the relief of suffering, whetherofbody or of mind. . 、[italics added]"6
Now es the IOM report,which has renamed so—called chronic fatigue syndrome(also called "myalgic encephalomyelitis") as "systemic exertion i ntolerancedisease"(SEID) and proposed essentiallyclinical criteriafor itsdiagnosis。
(Our word”clinical"isderived from the Greekklinikē ”bedside”-so, diagnosis madeatthe bedside)。
In brief, the SEID criteria entail thefollowing:
oSubstantial reductionor impairment inthe abilityto engage in pre -illness levels of occupational, educational, social, orpersonalactivities
oPostexertional malaise
o Unrefreshing sleep
o Either cognitive impairment or orthostatic intolerance (orboth)
Note that the SEIDcriteria do not require the identification of any specific biological, biochemical,or neuroanatomical abnormality、Rath er, theyentail a substantial degree of distress andimpairment、Tobeclear: the report did findevidence of astrongassociation of SEID with diminishednatural killer cellfunction;Epstein—Barr virus infection; decreasedcardiopulmonary function; and neuropsychiatric testing abnormalities—but these correlates are not required for diagnosis of SEID。
1Similarbiomarkers and associated abnormalities havebeen found in severalpsychiatricdisorders、For example,abnormal eyemovementscan distinguish persons with schizophrenia from normal persons wi th considerableaccuracy。
7 Nevertheless, currentdiagnostic criteria f or schizophrenia remain clinical, aswithSEID、
Already,theIOM report has attracted sharp criticism,with some physicians questioningthe lack of specificityintheSEIDcriteriaand worryingabout the potentialfor overdiagnosis andeven outright fraud.These risksarenottrivial, butI would argue that as physicians, our first duty istherecognitionand reliefof human suffering and incapacity, whet herwe can identifythe specificpathophysiology underlying the
patient'scondition。
With respectto SEID, the IOM reportmakes it abundantlyclear that this condition canhave profoundly adverseeffectson the sufferer’s social andvocational function。
1
To besure, we mustcontinue to investigate the biological underpinnings of SEID,just as we must in diseasestates such as schizophreniaand atypical facial pain。
When our patients are suffering and incapacitatedowing tosome internalprocess, however, we have bothclinical andethicalreasons to recognize that diseaseispresent, and to do our utmost totreat it.。