chronic obstructive pulmonary disease, 慢性閉塞性肺疾患
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/10/29 17:00:03」(JST)
慢性閉塞性肺疾患 Chronic Obstructive Pulmonary Disease (COPD) |
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喫煙に特有の小葉中心型肺気腫を表す肺の肉眼像。この固定され、切り取られた肺の外観のクローズアップは重質黒色炭素堆積物により満たされた多数の腔を表す。
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分類及び外部参照情報 | |
ICD-10 | J40–J44, J47 |
ICD-9 | 490–492, 494–496 |
OMIM | 606963 |
DiseasesDB | 2672 |
MedlinePlus | 000091 |
eMedicine | med/373 emerg/99 |
Patient UK | 慢性閉塞性肺疾患 |
疾患 | DALY (100万) |
割合 (%) |
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1 | 下気道感染症 | 94.5 | 6.2% |
2 | 下痢性疾患 | 72.8 | 4.8% |
3 | 大うつ病 | 65.5 | 4.3% |
4 | 虚血性心疾患 | 62.6 | 4.1% |
5 | HIV/AIDS | 58.5 | 3.8% |
6 | 脳血管疾患 | 46.6 | 3.1% |
7 | 未熟児、低出生体重 | 44.3 | 2.9% |
8 | 出生時仮死出生外傷 | 41.7 | 2.7% |
9 | 交通事故 | 41.2 | 2.7% |
10 | 新生児の感染症など | 40.4 | 2.7% |
11 | 結核 | 34.2 | 2.2% |
12 | マラリア | 34.0 | 2.2% |
13 | COPD | 30.2 | 2% |
14 | 屈折異常 | 27.7 | 1.8% |
15 | 成人発症性の難聴 | 27.4 | 1.8% |
16 | 先天異常 | 25.3 | 1.7% |
17 | アルコール使用障害 | 23.7 | 1.6% |
18 | 暴力 | 21.7 | 1.4% |
19 | 糖尿病 | 19.7 | 1.3% |
20 | 自傷行為怪我 | 19.6 | 1.3% |
慢性閉塞性肺疾患(まんせいへいそくせいはいしっかん; COPD:Chronic Obstructive Pulmonary Disease)は、代表的な慢性呼吸器疾患の一つであり[2]、肺胞の破壊や気道炎症が起き、緩徐進行性および不可逆的に息切れが生じる病気である。多くの場合、咳嗽や喀痰も見られる。死よりも恐ろしい病気として知られている[誰によって?]。
気管支喘息も閉塞性肺疾患の一つであるが、COPDとは異なる病態として区別されている。しばしば混同されているが、アレルギーを主病因とすること、通常は可逆的であること、好発年齢が若い、などの点でCOPDと異なる。COPDと喘息が合併する場合も知られている。
COPDの主要な原因はタバコ喫煙であり (間接的・受動的曝露を含む)[2]、少数は大気汚染や職業病などによる、有毒なガスや微粒子の吸入である[3]。日本名における慢性閉塞性肺疾患(COPD)は通称「たばこ病」であり、厚生労働省は以前「COPD」の名称として「たばこ病」や「肺たばこ病」を検討していた[4][5]。
2012年には世界で年間300万人がCOPDで死亡しており、これは世界における死因の6%を占める[2]。死者の90%以上は中低所得国である[2]。COPDは2030年までに、世界で3番目に成長している死因になるであろうとWHOは予測している[2]
以前より病理学的に「肺気腫」と呼ばれていた疾患概念と臨床的に「慢性気管支炎」と呼ばれていた疾患概念を統一したもので、慢性閉塞性肺疾患(COPD)として総称する疾患概念となった。2001年の国際ガイドライン(GOLD)および日本呼吸器学会の診療ガイドラインにこれらのことが明記され、日本および国際的な学会レベルでも本疾患概念は公式のものとなっている。元々、呼吸機能検査の分類上の呼称から、肺気腫、慢性気管支炎とも閉塞性肺疾患に分類されていた通り、COPDは閉塞性肺疾患に分類される。
日本呼吸器学会が2009年に発表した、「COPD(慢性閉塞性肺疾患)診断と治療のためのガイドライン 第3版 」によると下記のような定義が示されている。「COPDとは、タバコ煙を主とする有害物質を長期に吸入曝露することで生じた肺の炎症性疾患である。呼吸機能検査で正常に復すことのない気流閉塞を示す。気流閉塞は末梢気道病変と気腫性病変が様々な割合で複合的に作用することにより起こり、進行性である。臨床的には徐々に生じる体動時の呼吸困難や慢性の咳、痰を特徴とする。」
すべての喫煙者の肺には呼吸細気管支のレベルで炎症がみられる。COPDはそれらの末梢気道の病変を初発病変として、さらに炎症が慢性化するとともに周囲に進展し、進行するものと考えられている。末梢側に炎症が進展した場合、肺胞の破壊などのいわゆる気腫化が起こり、中枢側に炎症が波及した場合には、気管支粘液腺の肥大や気道上皮の浮腫、気道平滑筋の肥厚、気道分泌液の貯留、などのいわゆる気道病変が起こる。
病態の進展に伴い、肺過膨張および閉塞性換気障害、ガス交換障害が進行する。 COPDの初期は無症状である。肺過膨張と閉塞性換気障害が進行することにより、換気気流の抵抗が高くなったり横隔膜を始めとする呼吸筋が力学的に不利な状況におかれるようになったりするため、呼吸のためのエネルギー効率が低下し、徐々に労作時の息切れが顕在化する。息切れは、当初は階段や坂道などの昇りで自覚されるが、平地の歩行、ついで着替えや会話などの日常動作、さらには安静時にも生じるほど重症化する。息切れによって運動能が制限される状況となるが、呼吸数が増える際に起こる動的過膨張が関与する。 ガス交換障害は病初期は問題にならないが、気管支炎による抵抗の増加と重なる、肺胞の破壊が進むなどして重症化して低酸素血症となれば、日常の身体機能や臓器機能に影響するとともに、日常活動が制限されるようになるため、在宅酸素療法(HOT)などの酸素吸入療法が必要である(ガス交換機能が破壊されている上、換気気流の抵抗が大きくなるため呼吸としてほぼ破綻状態にある)。 COPDでは、感染などを契機として急速に病態が悪化することがあり、それらは急性増悪と呼ばれている。通常、急性増悪を一旦起こすと、一般状態レベルの低下が著しく見られ、回復には時間を要する。増悪を繰り返す場合ほど、生活の質や予後が悪い。 COPDは肺のみならず、全身性の炎症や筋力低下、骨粗しょう症、体重減少、虚血性心疾患、その他の種々の全身併存症が認められる。
発症の主因は、喫煙中のオキシダントをはじめバイオマス等の燃焼性物質による外因性因子である。COPD患者の90%は喫煙者であり[6]、非喫煙者に比べて喫煙者ではCOPDの発症リスクは6倍である[7]。また喫煙者の約10 ~ 15%がCOPDを発症するが、高齢者に限ると50%近くがCOPDである[8]。 ただし、喫煙者全員がCOPDを発症するわけではないことから、遺伝的α1-アンチトリプシン欠損症等やCHRNA3-5やHHIP等の内因性因子の提唱もある。
COPDは中枢気管支から末梢気道に至る気道に慢性炎症が生じる疾患である。炎症の主座により、主に肺胞の破壊が進行する気腫優位型(以前の肺気腫)と、主に中枢気道に炎症をおこす気道病変優位型(以前の慢性気管支炎)に分類されるが、これらが種々の割合で混在する。2009年に発行された日本呼吸器学会の診療ガイドライン第3版では、これらの分類は前者が「気腫型」、後者は「非気腫型」とされ、それらは主にCTなどの画像所見から判断することが明記された。
GOLDや日本呼吸器学会の分類では、COPDの重症度はスパイロメトリー検査により、1秒量の正常値に対するパーセント (FEV1/ predicted FEV1) で、0期(COPD予備群)および I 期 ~ IV期の5期に分類される。
病期 | 定義 |
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0期(COPD予備群) | 咳嗽、喀痰など症状はあるがスパイロメトリーは正常(まだCOPDではない) |
I 期(軽症) | 1秒率70%未満かつ1秒量が正常値の80%以上 |
II期(中等症) | 1秒率70%未満かつ1秒量が正常値の50%以上80%未満 |
III期(重症) | 1秒率70%未満かつ1秒量が正常値の30%以上50%未満 |
IV期(最重症) | 1秒率70%未満かつ1秒量が正常値の30%未満、あるいは1秒量が正常値の50%未満で慢性呼吸不全か右心不全を合併 |
当初は無症状であるが、進行していくにつれて労作時の息切れがみられるようになり、運動機能は低下していく。咳嗽、喀痰がみられることも多いが、見られないこともある。重症化すると、呼吸不全、高炭酸ガス血症となり予後も不良の状況となる。肺炎、気管支炎をおこしやすく、それを契機にした急性増悪を繰り返しやすい。また、重症者であるほど、急性増悪が重症化しやすい。全身の併存症を合併しやすく、特に気腫型では、呼吸効率の低下によるエネルギー消費亢進や食欲の低下などによるエネルギー摂取量の低下により栄養障害を起こしやすい。
COPDの増悪とは、呼吸困難、咳、喀痰といった症状が日常の生理的変動を超えて急性に悪化し、安定期の治療内容の変更を要するもののことである。ただし、他疾患(心不全、気胸、肺血栓塞栓症など)の合併による増悪は除外される。増悪の頻度で最も多いのが呼吸器感染症と大気汚染であるが約30%で増悪の原因は特定できない。急性増悪時には医療機関でパルスオキシメトリー、血液ガス分析、胸部単純Xp、心電図、血液検査(血算、CRP、電解質、肝腎機能など)の検査が、必要に応じて胸部CTや血液培養、喀痰Gram染色と培養、肺炎球菌尿中抗原などの感染症検査、心臓超音波検査、血清BNP濃度測定、凝固能検査などが行われる。重症度は呼吸器学会のCOPD(慢性閉塞性肺疾患)診断と治療のためのガイドライン(2014年1月現在 第4版)によって決められることが多い。
呼吸困難の悪化、喀痰量の増加、喀痰の膿性化のうち1つと、5日以内の上気道感染、他に原因のない発熱、喘鳴の増加、咳の増加、呼吸数あるいは心拍数の20%以上の増加のつち一つ以上が認められる。
呼吸困難の悪化、喀痰量の増加、喀痰の膿性化のうち2つ以上が認められる。
呼吸困難の悪化、喀痰量の増加、喀痰の膿性化のすべてが認められる。
増悪と判断した場合は薬物療法、酸素療法、換気補助療法がおこなわれる。薬物療法ではABCアプローチ(抗菌薬、気管支拡張薬、ステロイド)が用いられる。呼吸困難の第一選択は短時間作用性気管支拡張薬である。気管支拡張薬の吸入容量や回数を増加させる。効果が不十分な場合は短時間作用型抗コリン薬の併用を行い、これら治療を30分~60分ごと反復する。これらの吸入薬で効果不十分ならばテオフィリン薬の静脈投与を考慮する。安定期の病期がⅢ期以上の症例、呼吸困難が高度な症例、入院を要する省令では細菌感染がある場合もPSL30~40mg/dayの7~10日の投与が推奨されている。喀痰の膿性化が認められる場合は、細菌感染の可能性が高いため抗菌薬の使用が推奨される。
肺ガンなどの悪性疾患とは異なり、病気の進行が直接生命予後に呼吸不全として影響するまでは、相当の時間を要する。経過中に発症した肺炎などの感染症や肺ガン、虚血性心疾患が死亡原因となることが多く、生活の質を維持するケアとともにこれらの合併症を予防していく注意が生命予後を改善させる。酸素療法は低酸素血症に対して行い、予後を改善させる。呼吸機能(一秒量、最大吸気量、など)、運動能力、呼吸困難度、体重(栄養状態)、などの要素が予後悪化因子であることがわかっており、これらに対する治療が診療管理の課題と考えられている。外来治療では経口ペニシリン系薬、またはニューキノロン系薬の7~14日間の投与が行われる場合が多い。酸素療法はPaO2≧60Torr、またはSpO2≧90%を目標に調節する。
これらの初期治療に反応がなければ入院加療が検討される。入院治療が必要な例としては、呼吸困難の急激な増悪、チアノーゼや浮腫の出現、増悪に対する初期治療に無反応、重大な併存症、頻回の増悪、不整脈の出現、診断が不確実で鑑別診断が必要な場合、高齢者、在宅サポートが不十分などがあげられる。初期治療に反応しない重度の呼吸困難、錯乱、傾眠、昏睡などの精神状態の出現、酸素投与やNPPVにもかかわらず改善しない低酸素血症、または高二酸化炭素血症、あるいは呼吸性アシドーシス、IPPVが必要な状態、血行動態が不安定などではICU入院の適応となる。
WHOの試算では、2005年の世界のCOPD患者数(中等症以上)は8,000万人、うち年間300万人がCOPDにより命を落としている[2]。COPDは死亡原因の第4位を占めているが、今後10年間でさらに30%増加すると予測している[2]。
イギリスでは、患者数は300万人と推定されるが、うち200万人は未受診で、受診につながるのは50代になってからとされる[10]。
日本では、受診患者数は34万人(2001年)[11]。厚生労働省の統計によると、2005年に14,416人(男性11,018人、女性 3,398人、全死亡数の1.3%)がCOPDにより死亡し、死亡原因の10位、男性に限ると7位を占めている[12]。潜在患者数は530万人とされる(2004年)[13]。
1997年、WHOとアメリカ心肺血液研究所 (NHLBI)、アメリカ国立衛生研究所 (NIH) は、全世界的なCOPDの予防と治療を目的として、GOLD(Global Initiative for Chronic Obstructive Lung Disease、慢性閉塞性肺疾患に対するグローバルイニシアチブ)という国際機関を発足させた。2001年にCOPDの国際的ガイドラインを発表し[14]、その後改訂を重ね、COPDの診断、管理、治療の世界標準となっている。
成人喫煙者はCOPDの可能性がある。症状の目安は労作時の息切れ、咳、痰であるが、症状がなくても初期のCOPDの可能性を疑うべきである。
COPDは病期に応じて段階的な治療を行う。以前は治療法があまりないとして放置されることも多々みられたが、現在では治療可能な疾患であるとの概念が浸透している。ただし、COPDの病気自体は非可逆的な病態が大きな部分を占めており、肺胞破壊病変を修復するような根治的な治療は現時点では開発されていない。ただ、新たな薬剤開発や呼吸リハビリテーションの発展と普及によって、これまでよりも格段によい生活状態に改善できるようになっている。現在ある状況を可能な限り改善し、それを維持し、長期的な悪化を可能な限り最小限にとどめていくのが、現在の基本的なCOPD治療スタンスである。
すべての病期にわたり、禁煙、ワクチン接種などが勧められている。特に、無症状の軽症患者に対する禁煙指導はもっとも重要な治療ステップである。 第二期から長時間作用型気管支拡張剤を主とする薬物療法が行われる。テオフィリン、去痰薬なども必要に応じて選択される。 第三期以降、急性増悪を繰り返す患者では、吸入ステロイドが考慮される。 第三~四期の重症者では、必要に応じて、在宅酸素療法(HOT)[16]、非侵襲的陽圧呼吸、外科療法、などが考慮される。 第一期または二期の早い段階から、栄養指導を含めた呼吸リハビリテーションの実施が望ましく、施行が必須と考えられている。 重症者でも呼吸リハビリテーションの意義は非常に大い。全病期を通じて、短時間作用型の気管支拡張剤の頓用は必要に応じて選択される。 主に若年性の重症気腫型のCOPDに対し、本人の希望によって肺移植の適応が検討されることがある。
COPDの最大危険因子である喫煙をやめることで、COPDの進行を遅らせ、生命予後を改善する[17]。COPDにおける一秒量(FEV1.0)経年低下はCOPDの機能的な重症化の代表的な指標であるが、禁煙はいろいろな治療法のなかで、唯一進行抑制効果をもつ。
2013年のガイドライン改訂後は第一選択薬として、長時間作用性抗コリン薬(LAMA)と長時間作用性β2刺激薬(LABA)を同時に推奨している。
この他、必要に応じて 抗生物質、鎮咳薬、経口ステロイド薬、その他の併存症に対する薬剤など
運動療法がメインであり、それらはコンディショニング、自立を促すADLトレーニング、筋力・持久力トレーニングからなる。患者教育によって日常生活の適切な自己管理を行えるようにし、運動がライフスタイルに組み込まれていくことが重要である。重症者ではコンディショニングを中心にしたメニュー、軽症者では筋力・持久力トレーニングを中心にするなど、個々の症例の事情に応じたプログラムによって行われる。コンディショニングには、呼吸トレーニング(口すぼめ呼吸、腹式呼吸)や呼吸筋のリラクゼーション、四肢筋のケアなどが含まれている。排痰などのケアもコンディショニングの一部として行われる。栄養指導、感染管理、薬剤指導、メンタルサポート、その他包括的な内容がリハビリテーションの中に加えられている。
労作時息切れと肺の過膨張と特徴とする疾患概念は、1685年にWillisにより初めて記載された[18]。イタリアの解剖学者ジョヴァンニ・モルガーニ (en:Giovanni_Battista_Morgagni) は、この疾患患者の肺は剖検時に開胸してもしぼまないことを1761年の著書『 De Sedibus et Causis Morborum per Anatomen 』に記載し、1819年にフランスの内科医ルネ・ラエンネック)は「肺の過膨張状態で肺組織の萎縮を伴う疾患」として「肺気腫 emphysema 」という用語を導入した[18][19]。しかし当時、肺気腫は解剖病理学的疾患としての意味合いが強く、臨床症状としての過膨張や気流制限を客観的にとらえられるようになるには、1949年にティフェノーが開発した呼吸機能検査まで待たねばならなかった。
1950年代、人口増加と高年齢化、大気汚染や喫煙の増加等により、労作時息切れや喀痰の増加を特徴とする疾患患者が増加していた。これをイギリスでは「慢性気管支炎」と呼び、アメリカ合衆国では「肺気腫」と呼んだが、肺気腫・慢性気管支炎ともに気流制限を主要な特徴とするものの、両者の異同が問題となっていた。また気管支喘息の合併例や、鑑別の難しい例もみられた。そのため、慢性気管支炎、肺気腫、気管支喘息などに関する用語、定義、分類の統一を目指し、1958年イギリス学派が中心となりチバ・ゲスト・シンポジウム (Ciba Guest Symposium) が開催された。ここで慢性気管支炎は咳や痰の持続期間等の臨床症状に基づいて用いるべき用語であること、肺気腫は病理形態学的用語であることが提言された[20]。また同会でこれらの疾患概念を包括する用語として、「慢性非特異的肺疾患 chronic non-specific lung disease 」 が提案された[20]が、1965年この用語を止め、慢性気管支炎の用語を拡大して分類を行った[21]。
当時、慢性気管支炎は痰の分泌過多から感染をきたし、感染により進行して気流制限を呈するようになる、という病期のプロセスが想定されていた(後に否定される、後述)。
一方アメリカ学派は、チバ・ゲスト・シンポジウムの提言を受けて1962年アメリカ胸部学会(ATS)において慢性気管支炎、肺気腫、気管支喘息の三つの異同について討論し[22]、慢性気管支炎はイギリス学派と同様に臨床像により決定される疾患であること、肺気腫は主に病理形態学的な概念であることが確認されたが、肺気腫の臨床的側面について言及し、また上記三疾患を独立した疾患とするなど概念の完全な統一には至らなかった。その後イギリス学派のフレッチャーとアメリカ学派のバロウズらによる共同研究が行われ[23]、肺気腫・慢性気管支炎(および気管支喘息の一部)を包括した概念として「COPD chronic obstructive pulmonary disease 」[24]、「COLD chronic obstructive lung disease 」[25]といった用語が提唱され、またその他「CAO chronic airflow obstruction 」「CAL chronic airflow limitation 」などの用語も提案された。1965年アメリカ胸部疾患学会は、慢性びまん性の気流制限をきたす疾患を「COLD」と呼び、A型、B型、および分類不能のX型に分類した[26]。
1968年気流制限やガス交換は径2mm以下の末梢気道病変によることが示され[27]、COPDの病態として細気管支領域の病変が重視されるようになった。1975年アメリカ胸部疾患学会 (ATS) とアメリカ胸部医師会 (ACCP) の合同会議において気管支喘息は(オーバーラップはあるものの)COPDから切り離され、また末梢気道病変(細気管支炎)がCOPDの病態に関係することが指摘され、現在のCOPDの概念の基礎ができた。その後、慢性気管支炎にみられる気道分泌過多や気道感染は気流制限には関与しないこと、気流制限は末梢気道病変が関与するのに対し気道分泌過多は中枢気道病変が関与すること、気道分泌過多と気流制限は両者とも主に喫煙によるものであるが、その二つには相関がないことが示され、痰の分泌過多から感染をきたし、感染により進行して気流制限を呈するようになる、という慢性気管支炎の病期のプロセスは否定された[28]。末梢気道病変の重要性に関する知見が集積されてきたことにより、COPDの概念に見直しが迫られ、1986年ATSは、COPDと気管支喘息の診断と治療に関する声明を発表した[29]。ここでCOPDは非可逆的な気流制限であること、COPDには肺気腫、慢性気管支炎、末梢気道病変 (peripheral airway disease) の3つが含まれることが記載された。
また、疫学調査等からCOPD患者、COPD予備軍が非常に多く、世界の死亡者数の上位を占めることが示され、1990年代世界各国でCOPDの診断、治療、予防のガイドラインが出された。日本においても、日本呼吸器学会が1999年「COPD(慢性閉塞性肺疾患)の診断と治療のためのガイドライン」第1版を発表した。 さらに1997年、WHOとNHLBI、NIH は、全世界的なCOPDの予防と治療を目的として、GOLD(Global Initiative for Chronic Obstructive Lung Disease、慢性閉塞性肺疾患に対するグローバルイニシアチブ)という国際機関を発足させ、 2001年COPDガイドライン[14]を発表した。ここでは従来のガイドラインと違い、COPDを肺気腫、慢性気管支炎、末梢気道病変などの個々の疾患概念に分類したり異同を論じたりすることはせず、COPDを一つの疾患単位として扱うようになった。2013年には、従来のガイドラインに対して疾患定義の加筆修正、新知見を反映した薬物療法の追記、COPDの病態概念の追記、増悪の重要性、運動耐容能から身体活動性への概念の転換、災害などへの対応、文献のエビデンスレベルの記載と用語の統一、具体的な治療手順を示したアルゴリズムを新たに作成、などの改訂を行い第4版を発表した。
ウィキメディア・コモンズには、慢性閉塞性肺疾患に関連するカテゴリがあります。 |
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Chronic obstructive pulmonary disease | |
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Gross pathology of a lung showing centrilobular-type emphysema characteristic of smoking. This close-up of the fixed, cut lung surface shows multiple cavities lined by heavy black carbon deposits.
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Classification and external resources | |
Specialty | Pulmonology |
ICD-10 | J40–J44, J47 |
ICD-9-CM | 490–492, 494–496 |
OMIM | 606963 |
DiseasesDB | 2672 |
MedlinePlus | 000091 |
eMedicine | med/373 emerg/99 |
Patient UK | Chronic obstructive pulmonary disease |
MeSH | C08.381.495.389 |
Chronic obstructive pulmonary disease (COPD), also known as chronic obstructive lung disease (COLD), and chronic obstructive airway disease (COAD), among others, is a type of obstructive lung disease characterized by chronically poor airflow. It typically worsens over time. The main symptoms include shortness of breath, cough, and sputum production.[1] Most people with chronic bronchitis have COPD.[2]
Tobacco smoking is the most common cause of COPD, with a number of other factors such as air pollution and genetics playing a smaller role.[3] In the developing world, one of the common sources of air pollution is poorly vented cooking and heating fires. Long-term exposure to these irritants causes an inflammatory response in the lungs resulting in narrowing of the small airways and breakdown of lung tissue, known as emphysema.[4] The diagnosis is based on poor airflow as measured by lung function tests.[5] In contrast to asthma, the airflow reduction does not improve significantly with the administration of a bronchodilator.
COPD can be prevented by reducing exposure to known environmental risk factors. This includes efforts to decrease rates of smoking and to improve indoor and outdoor air quality. COPD treatments include stopping smoking, vaccinations, rehabilitation, and often inhaled bronchodilators and steroids. Some people may benefit from long-term oxygen therapy or lung transplantation.[4] In those who have periods of acute worsening, increased use of medications and hospitalization may be needed.
Worldwide, COPD affects 329 million people or nearly 5% of the population.[6] In 2013, it resulted in 2.9 million deaths up from 2.4 million deaths in 1990.[7] The number of deaths is projected to increase due to higher smoking rates and an aging population in many countries.[8] It resulted in an estimated economic cost of $2.1 trillion in 2010.[9]
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Wheezing
The sound of wheezing as heard with a stethoscope.
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The most common symptoms of COPD are sputum production, shortness of breath, and a productive cough.[10] These symptoms are present for a prolonged period of time[2] and typically worsen over time.[4] It is unclear if different types of COPD exist.[3] While previously divided into emphysema and chronic bronchitis, emphysema is only a description of lung changes rather than a disease itself, and chronic bronchitis is simply a descriptor of symptoms that may or may not occur with COPD.[1]
A chronic cough is often the first symptom to develop. When it persists for more than three months per year for at least two years, in combination with sputum production and without another explanation, there is by definition chronic bronchitis. This condition can occur before COPD fully develops. The amount of sputum produced can change over hours to days. In some cases the cough may not be present or may only occur occasionally and may not be productive. Some people with COPD attribute the symptoms to a "smoker's cough". Sputum may be swallowed or spat out, depending often on social and cultural factors. Vigorous coughing may lead to rib fractures or a brief loss of consciousness. Those with COPD often have a history of "common colds" that last a long time.[10]
Shortness of breath is often the symptom that bothers people the most.[11] It is commonly described as: "my breathing requires effort," "I feel out of breath," or "I can't get enough air in".[12] Different terms, however, may be used in different cultures.[10] Typically the shortness of breath is worse on exertion of a prolonged duration and worsens over time.[10] In the advanced stages it occurs during rest and may be always present.[13][14] It is a source of both anxiety and a poor quality of life in those with COPD.[10] Many people with more advanced COPD breathe through pursed lips and this action can improve shortness of breath in some.[15][16]
In COPD, it may take longer to breathe out than to breathe in.[17] Chest tightness may occur[10] but is not common and may be caused by another problem.[11] Those with obstructed airflow may have wheezing or decreased sounds with air entry on examination of the chest with a stethoscope.[17] A barrel chest is a characteristic sign of COPD, but is relatively uncommon.[17] Tripod positioning may occur as the disease worsens.[2]
Advanced COPD leads to high pressure on the lung arteries, which strains the right ventricle of the heart.[4][18][19] This situation is referred to as cor pulmonale, and leads to symptoms of leg swelling[10] and bulging neck veins.[4] COPD is more common than any other lung disease as a cause of cor pulmonale.[18] Cor pulmonale has become less common since the use of supplemental oxygen.[2]
COPD often occurs along with a number of other conditions, due in part to shared risk factors.[3] These conditions include ischemic heart disease, high blood pressure, diabetes mellitus, muscle wasting, osteoporosis, lung cancer, anxiety disorder and depression.[3] In those with severe disease a feeling of always being tired is common.[10] Fingernail clubbing is not specific to COPD and should prompt investigations for an underlying lung cancer.[20]
An acute exacerbation of COPD is defined as increased shortness of breath, increased sputum production, a change in the color of the sputum from clear to green or yellow, or an increase in cough in someone with COPD.[17] This may present with signs of increased work of breathing such as fast breathing, a fast heart rate, sweating, active use of muscles in the neck, a bluish tinge to the skin, and confusion or combative behavior in very severe exacerbations.[17][21] Crackles may also be heard over the lungs on examination with a stethoscope.[22]
The primary cause of COPD is tobacco smoke, with occupational exposure and pollution from indoor fires being significant causes in some countries.[1] Typically these exposures must occur over several decades before symptoms develop.[1] A person's genetic makeup also affects the risk.[1]
The primary risk factor for COPD globally is tobacco smoking.[1] Of those who smoke about 20% will get COPD,[24] and of those who are lifelong smokers about half will get COPD.[25] In the United States and United Kingdom, of those with COPD, 80–95% are either current smokers or previously smoked.[24][26][27] The likelihood of developing COPD increases with the total smoke exposure.[28] Additionally, women are more susceptible to the harmful effects of smoke than men.[27] In non-smokers, secondhand smoke is the cause of about 20% of cases.[26] Other types of smoke, such as marijuana, cigar, and water pipe smoke, also confer a risk.[1] Women who smoke during pregnancy may increase the risk of COPD in their child.[1]
Poorly ventilated cooking fires, often fueled by coal or biomass fuels such as wood and animal dung, lead to indoor air pollution and are one of the most common causes of COPD in developing countries.[29] These fires are a method of cooking and heating for nearly 3 billion people with their health effects being greater among women due to more exposure.[1][29] They are used as the main source of energy in 80% of homes in India, China and sub-Saharan Africa.[30]
People who live in large cities have a higher rate of COPD compared to people who live in rural areas.[31] While urban air pollution is a contributing factor in exacerbations, its overall role as a cause of COPD is unclear.[1] Areas with poor outdoor air quality, including that from exhaust gas, generally have higher rates of COPD.[30] The overall effect in relation to smoking, however, is believed to be small.[1]
Intense and prolonged exposure to workplace dusts, chemicals and fumes increase the risk of COPD in both smokers and nonsmokers.[32] Workplace exposures are believed to be the cause in 10–20% of cases.[33] In the United States they are believed to be related to more than 30% of cases among those who have never smoked and probably represent a greater risk in countries without sufficient regulations.[1]
A number of industries and sources have been implicated, including[30] high levels of dust in coal mining, gold mining, and the cotton textile industry, occupations involving cadmium and isocyanates, and fumes from welding.[32] Working in agriculture is also a risk.[30] In some professions the risks have been estimated as equivalent to that of one half to two packs of cigarettes a day.[34] Silica dust exposure can also lead to COPD, with the risk unrelated to that for silicosis.[35] The negative effects of dust exposure and cigarette smoke exposure appear to be additive or possibly more than additive.[34]
Genetics play a role in the development of COPD.[1] It is more common among relatives of those with COPD who smoke than unrelated smokers.[1] Currently, the only clearly inherited risk factor is alpha 1-antitrypsin deficiency (AAT).[36] This risk is particularly high if someone deficient in alpha 1-antitrypsin also smokes.[36] It is responsible for about 1–5% of cases[36][37] and the condition is present in about 3–4 in 10,000 people.[2] Other genetic factors are being investigated,[36] of which there are likely to be many.[30]
A number of other factors are less closely linked to COPD. The risk is greater in those who are poor, although it is not clear if this is due to poverty itself or other risk factors associated with poverty, such as air pollution and malnutrition.[1] There is tentative evidence that those with asthma and airway hyperreactivity are at increased risk of COPD.[1] Birth factors such as low birth weight may also play a role as do a number of infectious diseases including HIV/AIDS and tuberculosis.[1] Respiratory infections such as pneumonia do not appear to increase the risk of COPD, at least in adults.[2]
An acute exacerbation (a sudden worsening of symptoms)[38] is commonly triggered by infection or environmental pollutants, or sometimes by other factors such as improper use of medications.[39] Infections appear to be the cause of 50 to 75% of cases,[39][40] with bacteria in 25%, viruses in 25%, and both in 25%.[41] Environmental pollutants include both poor indoor and outdoor air quality.[39] Exposure to personal smoke and secondhand smoke increases the risk.[30] Cold temperature may also play a role, with exacerbations occurring more commonly in winter.[42] Those with more severe underlying disease have more frequent exacerbations: in mild disease 1.8 per year, moderate 2 to 3 per year, and severe 3.4 per year.[43] Those with many exacerbations have a faster rate of deterioration of their lung function.[44] Pulmonary emboli (blood clots in the lungs) can worsen symptoms in those with pre-existing COPD.[3]
COPD is a type of obstructive lung disease in which chronic incompletely reversible poor airflow (airflow limitation) and inability to breathe out fully (air trapping) exist.[3] The poor airflow is the result of breakdown of lung tissue (known as emphysema) and small airways disease (known as obstructive bronchiolitis). The relative contributions of these two factors vary between people.[1] Severe destruction of small airways can lead to the formation of large air pockets—known as bullae—that replace lung tissue. This form of disease is called bullous emphysema.[45]
COPD develops as a significant and chronic inflammatory response to inhaled irritants.[1] Chronic bacterial infections may also add to this inflammatory state.[44] The inflammatory cells involved include neutrophil granulocytes and macrophages, two types of white blood cell. Those who smoke additionally have Tc1 lymphocyte involvement and some people with COPD have eosinophil involvement similar to that in asthma. Part of this cell response is brought on by inflammatory mediators such as chemotactic factors. Other processes involved with lung damage include oxidative stress produced by high concentrations of free radicals in tobacco smoke and released by inflammatory cells, and breakdown of the connective tissue of the lungs by proteases that are insufficiently inhibited by protease inhibitors. The destruction of the connective tissue of the lungs is what leads to emphysema, which then contributes to the poor airflow and, finally, poor absorption and release of respiratory gases.[1] General muscle wasting that often occurs in COPD may be partly due to inflammatory mediators released by the lungs into the blood.[1]
Narrowing of the airways occurs due to inflammation and scarring within them. This contributes to the inability to breathe out fully. The greatest reduction in air flow occurs when breathing out, as the pressure in the chest is compressing the airways at this time.[46] This can result in more air from the previous breath remaining within the lungs when the next breath is started, resulting in an increase in the total volume of air in the lungs at any given time, a process called hyperinflation or air trapping.[46][47] Hyperinflation from exercise is linked to shortness of breath in COPD, as it is less comfortable to breathe in when the lungs are already partly full.[48]
Some also have a degree of airway hyperresponsiveness to irritants similar to those found in asthma.[2]
Low oxygen levels and, eventually, high carbon dioxide levels in the blood can occur from poor gas exchange due to decreased ventilation from airway obstruction, hyperinflation and a reduced desire to breathe.[1] During exacerbations, airway inflammation is also increased, resulting in increased hyperinflation, reduced expiratory airflow and worsening of gas transfer. This can also lead to insufficient ventilation and, eventually, low blood oxygen levels.[4] Low oxygen levels, if present for a prolonged period, can result in narrowing of the arteries in the lungs, while emphysema leads to breakdown of capillaries in the lungs. Both these changes result in increased blood pressure in the pulmonary arteries, which may cause cor pulmonale.[1]
The diagnosis of COPD should be considered in anyone over the age of 35 to 40 who has shortness of breath, a chronic cough, sputum production, or frequent winter colds and a history of exposure to risk factors for the disease.[10][11] Spirometry is then used to confirm the diagnosis.[10][49]
Spirometry measures the amount of airflow obstruction present and is generally carried out after the use of a bronchodilator, a medication to open up the airways.[49] Two main components are measured to make the diagnosis: the forced expiratory volume in one second (FEV1), which is the greatest volume of air that can be breathed out in the first second of a breath, and the forced vital capacity (FVC), which is the greatest volume of air that can be breathed out in a single large breath.[50] Normally, 75–80% of the FVC comes out in the first second[50] and a FEV1/FVC ratio of less than 70% in someone with symptoms of COPD defines a person as having the disease.[49] Based on these measurements, spirometry would lead to over-diagnosis of COPD in the elderly.[49] The National Institute for Health and Care Excellence criteria additionally require a FEV1 of less than 80% of predicted.[11]
Evidence for using spirometry among those without symptoms in an effort to diagnose the condition earlier is of uncertain effect and is therefore currently not recommended.[10][49] A peak expiratory flow (the maximum speed of expiration), commonly used in asthma, is not sufficient for the diagnosis of COPD.[11]
Grade | Activity affected |
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1 | Only strenuous activity |
2 | Vigorous walking |
3 | With normal walking |
4 | After a few minutes of walking |
5 | With changing clothing |
Severity | FEV1 % predicted |
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Mild (GOLD 1) | ≥80 |
Moderate (GOLD 2) | 50–79 |
Severe (GOLD 3) | 30–49 |
Very severe (GOLD 4) | <30 or chronic respiratory failure |
There are a number of methods to determine how much COPD is affecting a given individual.[10] The modified British Medical Research Council questionnaire (mMRC) or the COPD assessment test (CAT) are simple questionnaires that may be used to determine the severity of symptoms.[10] Scores on CAT range from 0–40 with the higher the score, the more severe the disease.[51] Spirometry may help to determine the severity of airflow limitation.[10] This is typically based on the FEV1 expressed as a percentage of the predicted "normal" for the person's age, gender, height and weight.[10] Both the American and European guidelines recommended partly basing treatment recommendations on the FEV1.[49] The GOLD guidelines suggest dividing people into four categories based on symptoms assessment and airflow limitation.[10] Weight loss and muscle weakness, as well as the presence of other diseases, should also be taken into account.[10]
A chest X-ray and complete blood count may be useful to exclude other conditions at the time of diagnosis.[52] Characteristic signs on X-ray are overexpanded lungs, a flattened diaphragm, increased retrosternal airspace, and bullae while it can help exclude other lung diseases, such as pneumonia, pulmonary edema or a pneumothorax.[53] A high-resolution computed tomography scan of the chest may show the distribution of emphysema throughout the lungs and can also be useful to exclude other lung diseases.[2] Unless surgery is planned, however, this rarely affects management.[2] An analysis of arterial blood is used to determine the need for oxygen; this is recommended in those with an FEV1 less than 35% predicted, those with a peripheral oxygen saturation of less than 92% and those with symptoms of congestive heart failure.[10] In areas of the world where alpha-1 antitrypsin deficiency is common, people with COPD (particularly those below the age of 45 and with emphysema affecting the lower parts of the lungs) should be considered for testing.[10]
Chest X-ray demonstrating severe COPD. Note the small heart size in comparison to the lungs.
A lateral chest x-ray of a person with emphysema. Note the barrel chest and flat diaphragm.
Lung bulla as seen on CXR in a person with severe COPD
A severe case of bullous emphysema
Axial CT image of the lung of a person with end-stage bullous emphysema.
COPD may need to be differentiated from other causes of shortness of breath such as congestive heart failure, pulmonary embolism, pneumonia or pneumothorax. Many people with COPD mistakenly think they have asthma.[17] The distinction between asthma and COPD is made on the basis of the symptoms, smoking history, and whether airflow limitation is reversible with bronchodilators at spirometry.[54] Tuberculosis may also present with a chronic cough and should be considered in locations where it is common.[10] Less common conditions that may present similarly include bronchopulmonary dysplasia and obliterative bronchiolitis.[52] Chronic bronchitis may occur with normal airflow and in this situation it is not classified as COPD.[2]
Most cases of COPD are potentially preventable through decreasing exposure to smoke and improving air quality.[30] Annual influenza vaccinations in those with COPD reduce exacerbations, hospitalizations and death.[55][56] Pneumococcal vaccination may also be beneficial.[55]
Keeping people from starting smoking is a key aspect of preventing COPD.[57] The policies of governments, public health agencies and anti-smoking organizations can reduce smoking rates by discouraging people from starting and encouraging people to stop smoking.[58] Smoking bans in public areas and places of work are important measures to decrease exposure to secondhand smoke and while many places have instituted bans more are recommended.[30]
In those who smoke, stopping smoking is the only measure shown to slow down the worsening of COPD.[59] Even at a late stage of the disease, it can reduce the rate of worsening lung function and delay the onset of disability and death.[60] Smoking cessation starts with the decision to stop smoking, leading to an attempt at quitting. Often several attempts are required before long-term abstinence is achieved.[58] Attempts over 5 years lead to success in nearly 40% of people.[61]
Some smokers can achieve long-term smoking cessation through willpower alone. Smoking, however, is highly addictive,[62] and many smokers need further support. The chance of quitting is improved with social support, engagement in a smoking cessation program and the use of medications such as nicotine replacement therapy, bupropion or varenicline.[58][61]
A number of measures have been taken to reduce the likelihood that workers in at-risk industries—such as coal mining, construction and stonemasonry—will develop COPD.[30] Examples of these measures include: the creation of public policy,[30] education of workers and management about the risks, promoting smoking cessation, checking workers for early signs of COPD, use of respirators, and dust control.[63][64] Effective dust control can be achieved by improving ventilation, using water sprays and by using mining techniques that minimize dust generation.[65] If a worker develops COPD, further lung damage can be reduced by avoiding ongoing dust exposure, for example by changing the work role.[66]
Both indoor and outdoor air quality can be improved, which may prevent COPD or slow the worsening of existing disease.[30] This may be achieved by public policy efforts, cultural changes, and personal involvement.[67]
A number of developed countries have successfully improved outdoor air quality through regulations. This has resulted in improvements in the lung function of their populations.[30] Those with COPD may experience fewer symptoms if they stay indoors on days when outdoor air quality is poor.[4]
One key effort is to reduce exposure to smoke from cooking and heating fuels through improved ventilation of homes and better stoves and chimneys.[67] Proper stoves may improve indoor air quality by 85%. Using alternative energy sources such as solar cooking and electrical heating is effective, as is using fuels such as kerosene or coal rather than biomass.[30]
There is no known cure for COPD, but the symptoms are treatable and its progression can be delayed.[57] The major goals of management are to reduce risk factors, manage stable COPD, prevent and treat acute exacerbations, and manage associated illnesses.[4] The only measures that have been shown to reduce mortality are smoking cessation and supplemental oxygen.[68] Stopping smoking decreases the risk of death by 18%.[3] Other recommendations include influenza vaccination once a year, pneumococcal vaccination once every 5 years, and reduction in exposure to environmental air pollution.[3] In those with advanced disease, palliative care may reduce symptoms, with morphine improving the feelings of shortness of breath.[69] Noninvasive ventilation may be used to support breathing.[69]
Pulmonary rehabilitation is a program of exercise, disease management and counseling, coordinated to benefit the individual.[70] In those who have had a recent exacerbation, pulmonary rehabilitation appears to improve the overall quality of life and the ability to exercise, and reduce mortality.[71] It has also been shown to improve the sense of control a person has over their disease, as well as their emotions.[72][needs update] Breathing exercises in and of themselves appear to have a limited role.[16] Pursed lip breathing exercises may be useful.[73][16]
Being either underweight or overweight can affect the symptoms, degree of disability and prognosis of COPD. People with COPD who are underweight can improve their breathing muscle strength by increasing their calorie intake.[4] When combined with regular exercise or a pulmonary rehabilitation program, this can lead to improvements in COPD symptoms. Supplemental nutrition may be useful in those who are malnourished.[74]
Inhaled bronchodilators are the primary medications used[3] and result in a small overall benefit.[75] There are two major types, β2 agonists and anticholinergics; both exist in long-acting and short-acting forms. They reduce shortness of breath, wheeze and exercise limitation, resulting in an improved quality of life.[76] It is unclear if they change the progression of the underlying disease.[3]
In those with mild disease, short-acting agents are recommended on an as needed basis.[3] In those with more severe disease, long-acting agents are recommended.[3] If long-acting bronchodilators are insufficient, then inhaled corticosteroids are typically added.[3] With respect to long-acting agents, it is unclear if tiotropium (a long-acting anticholinergic) or long-acting beta agonists (LABAs) are better, and it may be worth trying each and continuing the one that worked best.[77] Both types of agent appear to reduce the risk of acute exacerbations by 15–25%.[3] While both may be used at the same time, any benefit is of questionable significance.[78]
There are several short-acting β2 agonists available including salbutamol (Ventolin) and terbutaline.[79] They provide some relief of symptoms for four to six hours.[79] Long-acting β2 agonists such as salmeterol and formoterol are often used as maintenance therapy. Some feel the evidence of benefits is limited[80] while others view the evidence of benefit as established.[81][82] Long-term use appears safe in COPD[83] with adverse effects include shakiness and heart palpitations.[3] When used with inhaled steroids they increase the risk of pneumonia.[3] While steroids and LABAs may work better together,[80] it is unclear if this slight benefit outweighs the increased risks.[84]
There are two main anticholinergics used in COPD, ipratropium and tiotropium. Ipratropium is a short-acting agent while tiotropium is long-acting. Tiotropium is associated with a decrease in exacerbations and improved quality of life,[78][needs update] and tiotropium provides those benefits better than ipratropium.[85] It does not appear to affect mortality or the overall hospitalization rate.[86][needs update] Anticholinergics can cause dry mouth and urinary tract symptoms.[3] They are also associated with increased risk of heart disease and stroke.[87][88] Aclidinium, another long acting agent which came to market in 2012, has been used as an alternative to tiotropium.[89][90]
Corticosteroids are usually used in inhaled form but may also be used as tablets to treat and prevent acute exacerbations. While inhaled corticosteroids (ICS) have not shown benefit for people with mild COPD, they decrease acute exacerbations in those with either moderate or severe disease.[91] When used in combination with a LABA they decrease mortality more than either ICS or LABA alone.[92] By themselves they have no effect on overall one-year mortality and are associated with increased rates of pneumonia.[68] It is unclear if they affect the progression of the disease.[3] Long-term treatment with steroid tablets is associated with significant side effects.[79]
Long-term antibiotics, specifically those from the macrolide class such as erythromycin, reduce the frequency of exacerbations in those who have two or more a year.[93][94] This practice may be cost effective in some areas of the world.[95] Concerns include that of antibiotic resistance and hearing problems with azithromycin.[94] Methylxanthines such as theophylline generally cause more harm than benefit and thus are usually not recommended,[96] but may be used as a second-line agent in those not controlled by other measures.[4] Mucolytics may help to reduce exacerbations in some people with chronic bronchitis.[97] Cough medicines are not recommended.[79]
Supplemental oxygen is recommended in those with low oxygen levels at rest (a partial pressure of oxygen of less than 50–55 mmHg or oxygen saturations of less than 88%).[79][98] In this group of people it decreases the risk of heart failure and death if used 15 hours per day[79][98] and may improve people's ability to exercise.[99] In those with normal or mildly low oxygen levels, oxygen supplementation may improve shortness of breath.[100] There is a risk of fires and little benefit when those on oxygen continue to smoke.[101] In this situation some recommend against its use.[102] During acute exacerbations, many require oxygen therapy; the use of high concentrations of oxygen without taking into account a person's oxygen saturations may lead to increased levels of carbon dioxide and worsened outcomes.[103][104] In those at high risk of high carbon dioxide levels, oxygen saturations of 88–92% are recommended, while for those without this risk recommended levels are 94–98%.[104]
For those with very severe disease, surgery is sometimes helpful and may include lung transplantation or lung volume reduction surgery.[3] Lung volume reduction surgery involves removing the parts of the lung most damaged by emphysema allowing the remaining, relatively good lung to expand and work better.[79] Lung transplantation is sometimes performed for very severe COPD, particularly in younger individuals.[79]
Acute exacerbations are typically treated by increasing the usage of short-acting bronchodilators.[3] This commonly includes a combination of a short-acting inhaled beta agonist and anticholinergic.[38] These medications can be given either via a metered-dose inhaler with a spacer or via a nebulizer with both appearing to be equally effective.[38] Nebulization may be easier for those who are more unwell.[38]
Oral corticosteroids improve the chance of recovery and decrease the overall duration of symptoms.[3][38] They work equally well as intravenous steroids but appear to have fewer side effects.[105] Five days of steroids work as well as ten or fourteen.[106] In those with a severe exacerbation, antibiotics improve outcomes.[107] A number of different antibiotics may be used including amoxicillin, doxycycline and azithromycin; it is unclear if one is better than the others.[55] There is no clear evidence for those with less severe cases.[107]
For those with type 2 respiratory failure (acutely raised CO2 levels) non-invasive positive pressure ventilation decreases the probability of death or the need of intensive care admission.[3] Additionally, theophylline may have a role in those who do not respond to other measures.[3] Fewer than 20% of exacerbations require hospital admission.[38] In those without acidosis from respiratory failure, home care ("hospital at home") may be able to help avoid some admissions.[38][108]
COPD usually gets gradually worse over time and can ultimately result in death. It is estimated that 3% of all disability is related to COPD.[110] The proportion of disability from COPD globally has decreased from 1990 to 2010 due to improved indoor air quality primarily in Asia.[110] The overall number of years lived with disability from COPD, however, has increased.[6]
The rate at which COPD worsens varies with the presence of factors that predict a poor outcome, including severe airflow obstruction, little ability to exercise, shortness of breath, significantly underweight or overweight, congestive heart failure, continued smoking, and frequent exacerbations.[4] Long-term outcomes in COPD can be estimated using the BODE index which gives a score of zero to ten depending on FEV1, body-mass index, the distance walked in six minutes, and the modified MRC dyspnea scale.[111] Significant weight loss is a bad sign.[2] Results of spirometry are also a good predictor of the future progress of the disease but not as good as the BODE index.[2][11]
Globally, as of 2010, COPD affected approximately 329 million people (4.8% of the population).[6] The disease affects men and women almost equally, as there has been increased tobacco use among women in the developed world.[112] The increase in the developing world between 1970 and the 2000s is believed to be related to increasing rates of smoking in this region, an increasing population and an aging population due to less deaths from other causes such as infectious diseases.[3] Some developed countries have seen increased rates, some have remained stable and some have seen a decrease in COPD prevalence.[3] The global numbers are expected to continue increasing as risk factors remain common and the population continues to get older.[57]
Between 1990 and 2010 the number of deaths from COPD decreased slightly from 3.1 million to 2.9 million[113] and became the fourth leading cause of death.[3] In 2012 it became the third leading cause as the number of deaths rose again to 3.1 million.[114] In some countries, mortality has decreased in men but increased in women.[115] This is most likely due to rates of smoking in women and men becoming more similar.[2] COPD is more common in older people;[1] it affects 34–200 out of 1000 people older than 65 years, depending on the population under review.[1][53]
In England, an estimated 0.84 million people (of 50 million) have a diagnosis of COPD; this translates into approximately one person in 59 receiving a diagnosis of COPD at some point in their lives. In the most socioeconomically deprived parts of the country, one in 32 people were diagnosed with COPD, compared with one in 98 in the most affluent areas.[116] In the United States approximately 6.3% of the adult population, totaling approximately 15 million people, have been diagnosed with COPD.[117] 25 million people may have COPD if currently undiagnosed cases are included.[118] In 2011, there were approximately 730,000 hospitalizations in the United States for COPD.[119]
The word "emphysema" is derived from the Greek ἐμφυσᾶν emphysan meaning "inflate" -itself composed of ἐν en, meaning "in", and φυσᾶν physan, meaning "breath, blast".[120] The term chronic bronchitis came into use in 1808[121] while the term COPD is believed to have first been used in 1965.[122] Previously it has been known by a number of different names, including chronic obstructive bronchopulmonary disease, chronic obstructive respiratory disease, chronic airflow obstruction, chronic airflow limitation, chronic obstructive lung disease, nonspecific chronic pulmonary disease, and diffuse obstructive pulmonary syndrome. The terms chronic bronchitis and emphysema were formally defined in 1959 at the CIBA guest symposium and in 1962 at the American Thoracic Society Committee meeting on Diagnostic Standards.[122]
Early descriptions of probable emphysema include: in 1679 by T. Bonet of a condition of "voluminous lungs" and in 1769 by Giovanni Morgagni of lungs which were "turgid particularly from air".[122][123] In 1721 the first drawings of emphysema were made by Ruysh.[123] These were followed with pictures by Matthew Baillie in 1789 and descriptions of the destructive nature of the condition. In 1814 Charles Badham used "catarrh" to describe the cough and excess mucus in chronic bronchitis. René Laennec, the physician who invented the stethoscope, used the term "emphysema" in his book A Treatise on the Diseases of the Chest and of Mediate Auscultation (1837) to describe lungs that did not collapse when he opened the chest during an autopsy. He noted that they did not collapse as usual because they were full of air and the airways were filled with mucus. In 1842, John Hutchinson invented the spirometer, which allowed the measurement of vital capacity of the lungs. However, his spirometer could only measure volume, not airflow. Tiffeneau and Pinelli in 1947 described the principles of measuring airflow.[122]
In 1953, Dr. George L. Waldbott, an American allergist, first described a new disease he named "smoker's respiratory syndrome" in the 1953 Journal of the American Medical Association. This was the first association between tobacco smoking and chronic respiratory disease.[124]
Early treatments included garlic, cinnamon and ipecac, among others.[121] Modern treatments were developed during the second half of the 20th century. Evidence supporting the use of steroids in COPD were published in the late 1950s. Bronchodilators came into use in the 1960s following a promising trial of isoprenaline. Further bronchodilators, such as salbutamol, were developed in the 1970s, and the use of LABAs began in the mid-1990s.[125]
COPD has been referred to as "smoker's lung".[126] People with emphysema have been known as "pink puffers" or "type A" due to their frequent pink complexion, fast respiratory rate and pursed lips,[127][128] and people with chronic bronchitis have been referred to as "blue bloaters" or "type B" due to the often bluish color of the skin and lips from low oxygen levels and their ankle swelling.[128][129] This terminology is no longer accepted as useful as most people with COPD have a combination of both emphysema and chronic bronchitis.[2][128]
Many health systems have difficulty ensuring appropriate identification, diagnosis and care of people with COPD; Britain's Department of Health has identified this as a major issue for the National Health Service and has introduced a specific strategy to tackle these problems.[130]
Globally, as of 2010, COPD is estimated to result in economic costs of $2.1 trillion, half of which occurring in the developing world.[9] Of this total an estimated $1.9 trillion are direct costs such as medical care, while $0.2 trillion are indirect costs such as missed work.[131] This is expected to more than double by the year 2030.[9] In Europe, COPD represents 3% of healthcare spending.[1] In the United States, costs of the disease are estimated at $50 billion, most of which is due to exacerbation.[1] COPD was among the most expensive conditions seen in U.S. hospitals in 2011, with a total cost of about $5.7 billion.[119]
Infliximab, an immune-suppressing antibody, has been tested in COPD but there was no evidence of benefit with the possibility of harm.[132] Roflumilast shows promise in decreasing the rate of exacerbations but does not appear to change quality of life.[3] A number of new, long-acting agents are under development.[3] Treatment with stem cells is under study,[133] and while generally safe and with promising animal data there is little human data as of 2014.[134]
Chronic obstructive pulmonary disease may occur in a number of other animals and may be caused by exposure to tobacco smoke.[135][136] Most cases of the disease, however, are relatively mild.[137] In horses it is also known as recurrent airway obstruction and is typically due to an allergic reaction to a fungus contained in straw.[138] COPD is also commonly found in old dogs.[139]
<ref>
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国試過去問 | 「113C046」「104I012」「101F046」「103A016」「114B024」「114A002」「112E009」「105D008」「108B018」「108F011」「105H004」「107B030」「103I013」「105F009」「099B045」「113F038」「101B075」「111E009」「099B010」 |
リンク元 | 「骨粗鬆症」「慢性閉塞性肺疾患」「特発性肺線維症」「在宅酸素療法」「聴診」 |
関連記事 | 「COP」「CO」 |
E
※国試ナビ4※ [113C045]←[国試_113]→[113C047]
C
※国試ナビ4※ [104I011]←[国試_104]→[104I013]
BE
※国試ナビ4※ [101F045]←[国試_101]→[101F047]
BD
※国試ナビ4※ [103A015]←[国試_103]→[103A017]
C
※国試ナビ4※ [114B023]←[国試_114]→[114B025]
D
※国試ナビ4※ [114A001]←[国試_114]→[114A003]
D
※国試ナビ4※ [112E008]←[国試_112]→[112E010]
E
※国試ナビ4※ [105D007]←[国試_105]→[105D009]
E
※国試ナビ4※ [108B017]←[国試_108]→[108B019]
D
※国試ナビ4※ [108F010]←[国試_108]→[108F012]
D
※国試ナビ4※ [105H003]←[国試_105]→[105H005]
D
※国試ナビ4※ [107B029]←[国試_107]→[107B031]
C
※国試ナビ4※ [103I012]←[国試_103]→[103I014]
A
※国試ナビ4※ [105F008]←[国試_105]→[105F010]
C
※国試ナビ4※ [099B044]←[国試_099]→[099B046]
AC
※国試ナビ4※ [113F037]←[国試_113]→[113F039]
D
※国試ナビ4※ [101B074]←[国試_101]→[101B076]
C
※国試ナビ4※ [111E008]←[国試_111]→[111E010]
E
※国試ナビ4※ [099B009]←[国試_099]→[099B011]
遺伝性症候群 | 骨形成不全症 |
特発性若年性骨粗鬆症 | |
慢性後天性症候群 | 胆道閉鎖症、チアノーゼ性心疾患 |
急性後天性症候群 | 身体の固定、体動制限 |
後天性代謝異常 | 甲状腺中毒、クッシング症候群、カルシウム欠乏、壊血病 |
新生物による | 白血病、原発/転移性悪性腫瘍 |
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臨床診断名 | IPF | NSIP | BOOP/COP |
病理組織像 | UIP | OP | |
発症様式 | 慢性 | 慢性/亜急性 | 亜急性 |
BALF所見 | リンパ球± | CD8↑ | CD8↑ |
予後 | 不良 | 良好(時に不良) | 良好 |
分布 | 斑状,不均質, 胸膜下・小葉辺縁 | びまん性,均質 | 小葉中心性 |
時相 | 多様 | 均質 | 均質 |
間質への細胞浸潤 | 少ない | 通常多い | やや多い |
胞隔の炎症 | 軽度,斑状 | びまん性,多彩 | 軽度 |
線維芽細胞巣 | 多数 | まれ | なし |
肺胞内マクロファージ集積 | 巣状 | 巣状 | なし |
肺胞腔内線維化 | まれ | しばしば | 多数 |
顕微鏡的蜂巣肺(肺胞虚説) | 高頻度 | 通常なし(一部に認める) | なし |
硝子膜 | なし | なし | なし |
し支えない。
連続性 | ~ | 吸気時 | strider | 気道狭窄音 | 気道狭窄音 | |||
連続性 | 低調整 | 呼気時 | rhonchi | ≦200Hz | >250ms | COPD、気管支喘息、気管支拡張症、びまん性汎細気管支炎 | ||
連続性 | 高調性 | 呼気時 | wheeze | ≧400Hz | >250ms | 気管壁がフラッタリングすることで発生 | COPD、気管支喘息、気管支拡張症、びまん性汎細気管支炎。気管支喘息では複数の様々な音声が発生し、random polyphonic wheezes | |
連続性/断続性 | 高調性 | 吸気時 | squawk | ≦100ms | 吸気により細い気管支が再開放する時に、気管支壁が短時間共振し発生 | 間質性肺炎、肺線維症、びまん性汎細気管支炎、過敏性肺臓炎、ウェゲナー肉芽腫症、気管支拡張症、石綿肺 | ||
断続性 | 低調整 | 吸気時 | coarse crackle | early inspiratory crackle | 250-500Hz | 10~25ms | 太い気道内の分泌液の膜の前後に、吸気時の圧較差が生じ、それが破れるときに発生。個々の音はfine crackleより長め | 気管支拡張症、COPD、びまん性汎細気管支炎、進行した肺水腫 |
断続性 | 高調性 | 吸気時 | fine crackle | late inspiratory crackle | 500~1000Hz | ≦5ms | 呼気時に閉塞した末梢気道が吸気時に再開放されるときに発生 | 特発性間質性肺炎、特発性肺線維症、石綿肺、過敏性肺炎、肺水腫初期 |
<youtube>http://www.youtube.com/watch?v=yiVbKc4-CH0</youtube> <youtube>http://www.youtube.com/watch?v=oCsNpzEQ4OA</youtube>
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