대한내과학회지 : 제 77 권제 4 호 2009 특집 (Special Review) - Updates of COPD COPD 의진단 영남대학교의과대학내과학교실 이관호 Diagnosis of chronic obstructive pulmonary disease Kwan-Ho Lee, M.D., Ph.D Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea The chronic obstructive pulmonary disease (COPD) can be diagnosed by spirometry. COPD is confirmed when a patient who has symptoms that are compatible with COPD is found to have airflow obstruction (post expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio less than 0.70). However, the FEV1/FVC ratio decreases with age and can create a risk for underdiagnosis in young patients and overdiagnosis in older patients. Therefore, clear consensus definition of diagnostic criteria for COPD in older patients is needed. The staging system using FEV1 alone has been criticized for underestimating the importance of the extrapulmonary manifestation of COPD in predicting outcome. The BODE (Body mass index, Obstruction, Dyspnea, Exercise capacity) index provides better prognostic information than the FEV1 alone and can be used to assess therapeutic response. (Korean J Med 77:401-406, 2009) Key Words: Chronic obstructive pulmonary disease; Diagnosis 서 론 임상증상 COPD는조기에진단하면증상을예방하고, 악화빈도를감소시킬수있고, 운동능력을향상시키며수명을연장할수있다. 그러나실제로 COPD는진단이잘되지않고있으며흡연자의 15~20% 정도만진단되고있다 1-3). COPD는흡연과같은위험인자에노출되고임상적으로기침, 객담, 호흡곤란등이있는환자에서폐기능검사를하여확진한다. 증상이나진찰에의한진단은민감도와예민도가높지않아서진단되지않거나과잉진단될수있다. COPD 는폐기능검사에서 FEV 1/FVC 비가 70% 이하일때확진할수있으며 COPD 병기는 FEV 1% 에따라결정한다 4). COPD는대부분 20갑년이상의흡연력이있는 40대이상에서발병하며처음에는기침과객담이생기고, 50~60대가되면활동시호흡곤란이생긴다. 주된증상은기침, 객담, 호흡곤란이며일단발병하면점점진행하며증상의특징은다음과같다. 1. 기침 COPD 환자의가장흔한증상은기침이다. 기침은호흡곤란보다먼저생기기도하지만대부분환자에서는호흡곤란과동시에생긴다. 기침으로일상생활이불편할수있으나 * This work was supported by grant No. RTI04-01-04 from the Regional Technology Innovation Program of the Ministry of Commerce, Industry, and Energy (MOCIE). - 401 -
- The Korean Journal of Medicine: Vol. 77, No. 4, 2009 - 대부분환자는불편함을모르고그냥지내기도한다. 기침정도와폐기능과는상관관계가없는것으로알려져있다 1). 기침은만성적으로지속되며초기의흉부엑스선사진은정상이다. 흉부엑스선사진이정상인만성기침의감별질환은표 1과같다 4). 2. 객담객담은서서히생기며대개소량으로시작한다. 흡연량이많을수록객담양은많다. 객담은점성이대부분이며감염이있으면화농성으로변하며, 화농성객담은 2~3주지나면호전된다. 금연하면객담은서서히없어진다 1-4). 3. 객혈 COPD에서객혈의특징은객담에묻어나오는것이며, 만성기관지염에서호흡기감염이있을때잘생긴다. 객혈이있으면폐암과같은다른원인질환과감별하여야한다 1). 4. 호흡곤란대부분환자는활동할때호흡곤란을느끼지만호흡곤란을느끼지못하는경우도있다. COPD 가진행되면활동시호흡곤란도점점더심해진다. 호흡곤란은주로동적과팽창 (dynamic hyperinflation) 으로생기며과팽창은호흡빈도가빨라질수록증가되어호흡곤란이더욱심해진다. 환자들은호흡곤란이심해지면활동을하지않게되고이에따라말초근육기능이감소되면서점점활동은어렵게된다 2,3). 5. 천명음천명음은호흡시쌕쌕거리는소리며청진기없이도들을 수있다. 우리나라에서는숨이차거나기침이있으면먼저 천식 으로생각하는경향이있기때문에천식이있다는환자의말에의존하지말고반드시 COPD 와감별하여야한다 4). 진찰소견초기에는특징적진찰소견은없으며진찰소견만으로는 COPD의진단에는큰도움이되지않는다 4). 1. 시진호흡곤란이있으면호흡횟수가빨라지고심하면입술을오므리고호흡을하게되고목의보조호흡근을최대한사용하게되어목부위가호흡시함몰된다. 흉곽은전-후직경이커지는술통형소견을보이고늑간이함몰된다. COPD 가진행되어우측심부전이합병되면발목이나하지부종이생긴다. 호흡곤란이심하면입술이나손-발끝에청색증이생긴다. 2. 촉진과타진 COPD 환자에서는목소리진동음이감소되고, 심첨박동도만지기어려우며, 타진시고막 (tympanic) 음이증가한다. 3. 청진객담이있으면건성수포음 (rhonchi) 이들리고기도폐쇄가있으면천명음이들린다. 천명음은기관지폐쇄가약할때는호기에만들리지만진행되면호기와흡기에모두들린다. 천명음의심한정도와기도폐쇄정도와는상관관계가적으며기도폐쇄가매우심할때는오히려천명음은들리지않고호흡음이감소된다 1,3). Table 1. Causes of chronic cough with a normal chest X-ray Intrathoracic diseases Chronic obstructive pulmonary disease Central bronchial tumor Bronchiectasis Interstitial lung disease Bronchial asthma Endobronchial tuberculosis Left heart failure Extrathoracic diseases Postnasal drip Gastroesophageal reflux Drugs (e.g., angiotensin converting enzyme inhibitor) 흉부엑스선촬영 1. 단순흉부엑스선검사 COPD 진단에는큰의미가없지만다른질환과의감별에유용하다. COPD 가진행되면특징적인만성기관지염과폐기종소견이일부환자에서나타난다. 만성기관지염이심할때는기관지- 혈관음영이증가한다 ( 그림 1). 폐기종이우세하면과팽창, 횡격막의편평화, 흉골뒤공간의과팽창, 폐혈관음영감소등과같은소견이있다. 심장음영은작고길게보이며폐동맥고혈압이합병된경우폐동맥확장소견이나타난다 ( 그림 2) 1-4). - 402 -
- Kwan-Ho Lee. Diagnosis of chronic obstructive pulmonary disease - Table 2. Clinical manifestations suspected to be chronic obstructive pulmonary disease Chronic cough Chronic sputum Dyspnea Risk factors exposing history Intermittent or daily Often daily Chronic sputum production Progressive Continuous Shortness of breath, chest tightness Dyspnea on exertion Exacerbation when respiratory infection Smoking Occupational dusts Cooking or bio-fuel gas Figure 1. Chest X-ray of chronic bronchitis. COPD 환자에서폐동맥색전증의진단이증가되고있다 1-3). 폐기능검사 1. 적응임상적병력에서 COPD가의심되면폐기능검사를실시하여기도폐쇄여부를확인하여야한다. 호흡곤란이있는모든환자에서폐기능검사를실시하여야하며호흡곤란이없어도흡연, 기침, 객담등의소견이있으면선별검사로폐기능검사를하여야한다. 일반적으로표 2와같은증상이있으면 COPD를의심하고폐기능검사를실시한다 4). 2. 판정기준 Figure 2. Chest X-ray of emphysema. 2. 흉부전산화단층촬영흉부전산화단층촬영도진단에반드시필요한검사는아니지만다른질환과의감별에유용하며, 특히고해상도단층촬영은그림 3과같이폐기종의조기진단과형태, 대기포성폐기종의평가와기관지확장증이나간질성폐질환과의감별진단에도움이된다. 최근흉부전산화단층촬영이증가되면서 COPD를진단하는표준폐기능검사법은폐활량측정법 (spirometry) 이다. 폐기능검사는 COPD의진단, 중증도를판정하거나폐기능감소진행을확인할수있다. 기도폐쇄는기관지확장제투여후의 1초간강제호기량 (FEV 1) 과노력성폐활량 (FVC) 의비 (FEV 1/FVC) 로판정한다. FEV 1/FVC 비가 70% 미만이면 COPD로진단한다 4). FEV 1/FVC 비는나이가들수록감소된다. 폐기능에의한폐쇄성환기장애의정의는가이드라인에따라차이가있다. GOLD 가이드라인에의한진단기준은 FEV 1/FVC 비가나이에관계없이 70% 이하인경우로정의하고있다. 유럽호흡기학회에서정한기준은이비가나이, 성별등에따라보정한수치이며남자에서는 FEV 1/FVC 비가 88% 이하, 여자에서는 89% 이하로정의하고있다 ( 그림 4) 5). 영국흉부학회의진단기준은가장엄격한기준으로이비가 70% 이하이면서 FEV 1 이정상예측치의 80% 이하일때로정의하고있다. 진단기준중유럽호흡기학회의기준을제외하고는대부분의나라 - 403 -
- 대한내과학회지 : 제 77 권제 4 호통권제 590 호 2009 - Figure 4. Theoretical values of airways obstruction, as determined by FEV 1/FVC percentage of predicted according to major respiratory guidelines, at each age group, for men. Figure 3. CT scan of emphysema. Figure 5. Diagram depicting the decline of the lower limit of normal of the forced expiratory volume in 1 second (FEV 1)/forced vital capacity (FVC) ratio with ageing, among white neversmoking women in the Third National Health and Nutrition Examination Survey. The dark shaded portion depicts elderly subjects who are potentially overdiagnosed and the light shaded portion depicts younger adults who are potentially underdiagnosed with obstructive lung disease. 에서 FEV 1 치와관계없이 FEV 1/FVC 의고정비로진단하고있다. 그러나실제로젊은이에서이기준을적용할경우과소 진단될수있으며, 노인에서는과잉진단될수있다 ( 그림 5). 나이가들수록폐포벽의파괴등으로 FEV 1 은감소되고폐활량, 잔기량등이증가됨에따라 FVC는증가되어 FEV 1/FVC 비는감소될수있다. 따라서만성폐쇄성폐질환의진단기준으로 FEV 1/FVC 70% 이하라는고정비를사용할경우에젊은이에서는과소진단될수있고노인에서는과잉진단될수 Figure 6. Flow-volume curve of pulmonary function test in patient with chronic obstructive pulmonary disease. 있기때문에나이를보정한 FEV 1/FVC 비의제정이필요하겠다 6-11). 유량-용적곡선에서는그림 6과같이호기시유속의감소로호기말기에오목하게들어가모습 (concave) 혹은알파벳의 U 모양으로보이고폐용적은과팽창된소견을보인다. 폐확산능검사는폐기종에서감소되며일부에서천식과감별진단에도움된다 1-3). 동맥혈가스검사 초기에는고탄산혈증소견없이경한저산소혈증소견을 - 404 -
- 이관호. COPD 의진단 - 보이나진행되면고탄산혈증과호흡성산혈증이나타난다. 저산소혈증은활동을하거나, 급성악화혹은수면중에더나빠진다. 진행된 COPD, 특히 FEV 1 이정상예측치의 50% 이하이거나만성호흡부전, 우심실부전소견이있으면반드시 동맥혈가스검사를실시하여야한다 1-4). 우리나라에서호흡기질환에의한장애진단을발급하기위해서는동맥혈가스검사를하여서판단하여야한다. 기타검사 심전도검사는부정맥, 폐동맥고혈압, 우심실부전, 폐성심, 좌실실부전이의심되면실시한다. COPD 가진행되면일반혈액검사에서적혈구증다증이나타난다. 증증도평가 병기판정은증상의정도, 폐활량측정소견, 호흡부전이나우심부전의여부에따라다음과같은 5단계로판정하며 ( 표 3) 치료도이단계에따라서실시한다 4). GOLD 가이드라인에의한 COPD의중증도판정은 FEV 1 에의해서만결정되기때문에 COPD의예후에중요한영향을주는폐외증상이반영되지않은문제점이있다. 최근에는병기판정기준으로체중 (BMI), 기도폐쇄 (FEV 1), 호흡곤란 (MRC 점수 ), 운동능력 (6분걷는거리 ) 의네가지요소를고 Table 3. Spirometric classification of chronic obstructive pulmonary disease severity based on post-bronchodilator FEV 1 Stage Characteristics Stage 1: mild FEV 1 / FVC <70% FEV 1 80% (predicted) Chronic symptoms (cough, sputum) with or without Stage 2: moderate FEV 1 / FVC <70% 50% FEV 1 <80% Chronic symptoms (cough, sputum) with or without Stage 3: severe FEV 1 / FVC <70% 30% FEV 1 <50% Chronic symptoms (cough, sputum) with or without Stage 4: very severe FEV 1 / FVC <70% FEV 1 <30% or FEV 1 <50% with chronic respiratory failure 려한방법 (BODE Index) 으로판정하는방법이관심을받고 있다 12). Table 4. Differential diagnosis of COPD COPD Onset in mid-life Symptoms slowly progressive Long history of tobacco smoking Dyspnea during exercise Largely irreversible airflow limitation Asthma Onset early in life(often childhood) Symptoms vary from day to day Symptoms at night/early morning Allergy, rhinitis, and/or eczema also present Family history of asthma Largely reversible airflow limitation Congestive heart failure Fine basilar crackles on auscultation Chest X-ray shows dilated heart Pulmonary function tests indicate volume restriction, not airflow limitation Bronchiectasis Large volumes of purulent sputum Commonly associated with bacterial infection Coarse crackles/clubbing on auscultation Chest X-ray/CT shows bronchial dilation, bronchial wall thickening. Tuberculosis Onset all ages Chest X-ray shows lung infiltrate Microbiological confirmation High local prevalence of tuberculosis Obliterative bronchiolitis Diffuse panbronchiolitis 감별진단 COPD와가장감별이어려운질환은기관지천식이다. 기관지천식과는흉부엑스선촬영, 폐활량측정법으로는감별하기어려우며, 임상소견과더불어혈청표지자검사, 기관지천식유발검사를하여야한다. COPD 와감별해야할질환은표 4와같다 4). Onset in younger age, nonsmokers May have history of rheumatoid arthritis or fume exposure CT on expiration shows hypodense areas Most patients are male and nonsmokers Almost all have chronic sinusitis Chest X-ray and HRCT show diffuse small centrilobular nodular opacities and hyperinflation - 405 -
- The Korean Journal of Medicine: Vol. 77, No. 4, 2009 - 요 COPD는폐기능검사에서 FEV 1/FVC 비가 70% 이하일때진단한다. FEV 1/FVC 비는나이가증가함에따라정상적으로도감소되기때문에절대치의단점을보완하기위해서는나이에대한보정이필요하겠다. 현재까지병기판정은 FEV 1 단독으로하고있으나 COPD 환자에서폐외증상이예후에중요한영향을주기때문에체중, 기도폐쇄, 호흡곤란정도, 운동능력을고려한 BODE지수가병기결정에중요한방법이될것으로예상된다. 약 중심단어 : 만성폐쇄성폐질환 ; 진단 REFERENCES 1) Shapiro SD, Snider GL, Rennard SI. Chronic bronchitis and emphysema. In: Murray JF and Nadal JA. Textbook of respiratory medicine, 4th ed. p. 1115-1125, Philadelphia, W.B. Saunders, 2005 2) Reilly J, Silverman EK, Shapiro SD. CHRONIC OBSTRUCTIVE PULMONARY DISEASE. In: Braunwald E, Fauci AS, Kasper D, Hauser SL, Longo DL, Jameson JL. Harrison's principles of internal medicine, 16th ed. p. 1147-1150, New York, McGraw-Hill, 2005 3) KH Lee. Clinical manifestations and diagnosis. Journal of The Korean Medical Association. 49:313-320, 2007 4) Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management and Prevention of Chronic Obstructive Lung Disease. NHLBI/WHO workshop report. Bethesda, National Heart, Lung and Blood Institute, April 2001:Updte of the Management Sections, GOLD website www.goldcopd.com). Date updated: 1 July 2006 5) Hardie JA, Buist AS, Vollmer WM, Ellingsen I, Bakke PS, Mørkve O. Risk of over-diagnosis of COPD in asymptomatic elderly never-smokers. Eur Respir J 20:1117-1122, 2002 6) KH Lee. Chronic obstructive pulmonary disease in the older patient. Korean J Med 75:149-152, 2008 7) Celli BR, Halbert RJ, Isonaka S, Schau B. Population impact of different definitions of airway obstruction. Eur Respir J 22: 268-273, 2003 8) Medbø A, Melbye H. Lung function testing in the elderly-can we still use FEV1/FVC<70% as a criterion of COPD? Respir Med 101:1097-1105, 2007 9) Hansen JE, Sun XG, Wasserman K. Spirometric criteria for airway obstruction: Use percentage of FEV1/FVC ratio below the fifth percentile, not < 70%. Chest 131:349-355, 2007 10) Mannino DM, Sonia Buist A, Vollmer WM. Chronic obstructive pulmonary disease in the older adult: what defines abnormal lung function? Thorax 62:237-241, 2007 11) Lindberg A, Bjerg A, Rönmark E, Larsson LG, Lundbäck B. Prevalence and underdiagnosis of COPD by disease severity and the attributable fraction of smoking Report from the Obstructive Lung Disease in Northern Sweden Studies. Respir Med 100:264-272, 2006 12) Celli B, Cote C, Marin J, Casanova C, Montes de Oca M, Mendez R, Pinto-Plata V, Cabral H. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med 350:1005 1012, 2004-406 -