RT Book, Section
A1 Silverman, Edwin K.
A1 Crapo, James D.
A1 Make, Barry J.
A2 Loscalzo, Joseph
A2 Fauci, Anthony
A2 Kasper, Dennis
A2 Hauser, Stephen
A2 Longo, Dan
A2 Jameson, J. Larry
SR Print(0)
ID 1198709932
T1 Chronic Obstructive Pulmonary Disease
T2 Harrison's Principles of Internal Medicine, 21e
YR 2022
FD 2022
PB McGraw-Hill Education
PP New York, NY
SN 9781264268504
LK accessmedicine.mhmedical.com/content.aspx?aid=1198709932
RD 2024/04/24
AB Chronic  obstructive  pulmonary  disease  (COPD)  is  defined  as  a  disease  state  characterized  by  persistent  respiratory  symptoms  and  airflow  obstruction  (https://goldcopd.org/2021-gold-reports/).  COPD  includes  emphysema,  an  anatomically  defined  condition  characterized  by  destruction  of  the  lung  alveoli  with  air  space  enlargement;  chronic  bronchitis,  a  clinically  defined  condition  with  chronic  cough  and  phlegm;  and/or  small  airway  disease,  a  condition  in  which  small  bronchioles  are  narrowed  and  reduced  in  number.  The  classic  definition  of  COPD  requires  the  presence  of  chronic  airflow  obstruction,  determined  by  spirometry,  that  usually  occurs  in  the  setting  of  noxious  environmental  exposures—most  commonly  products  of  combustion,  cigarette  smoking  in  the  United  States,  and  biomass  fuels  in  some  other  countries.  Host  factors  such  as  abnormal  lung  development  and  genetics  can  lead  to  COPD.  Emphysema,  chronic  bronchitis,  and  small  airway  disease  are  present  in  varying  degrees  in  different  COPD  patients.  Patients  with  a  history  of  cigarette  smoking  without  chronic  airflow  obstruction  may  have  chronic  bronchitis,  emphysema,  and  dyspnea.  Although  these  patients  are  not  included  within  the  classic  definition  of  COPD,  they  may  have  similar  disease  processes.  Respiratory  symptoms  and  other  features  of  COPD  can  occur  in  subjects  who  do  not  meet  a  definition  of  COPD  based  only  on  airflow  obstruction  determined  by  spirometric  population  thresholds  of  normality.  Investigators  in  the  COPDGene  study  recently  proposed  a  multidimensional  approach  to  COPD  diagnosis,  which  is  based  on  domains  of  environmental  exposures,  respiratory  symptoms,  imaging  abnormalities,  and  physiologic  abnormalities.