Diagnosis of COPD for Physicians
While ambient air pollution, occupational dust/chemicals and childhood infections can predispose one to the development of COPD, cigarette smoking continues to be the overwhelming cause (>90%) of COPD in the United States. Of the top five causes of death in the United States, only COPD is on the rise.
Early Diagnosis
Early diagnosis is crucial - all smokers, especially those with cough or sputum production, should have periodic simple spirometry and should be engaged in smoking cessation efforts. Special consideration should be give for those individuals who have greater than 20 pack years history or smoking. There is significant evidence that these individuals are at greatest risk for developing respiratory and cardiovascular problems related to their smoking. The diagnosis of COPD should be considered in any patient who has:
- chronic cough
- sputum production
- dyspnea
- history of exposure to risk factors for the disease
The diagnosis can only be confirmed by spirometry with a reversibility test.
COPD Severity
Assessment of COPD severity is based on the following:
- the patient's level of symptoms
- the severity of the spirometric abnormality
- the presence of complications such as respiratory failure and right heart failure
| Table 1 - Classification of COPD by Severity |
| Stage |
Characteristics |
| 0: At Risk |
- normal spirometry
- chronic symptoms (cough, sputum production)
|
| I: Mild COPD |
- FEV 1/FVC < 70%
- FEV 1 ≥ 80% predicted
- with or without chronic symptoms (cough, sputum production)
|
| II: Moderate COPD |
- FEV 1 IFVC < 70%
- 50% ≤ FEV 1 < 80% predicted
- with or without chronic symptoms (cough, sputum production)
|
| III: Severe COPD |
- FEV1/FVC < 70%
- 30% ≤ FEV 1 < 50% predicted
- with or without chronic symptoms (cough, sputum production)
|
| IV:Very Severe COPD |
- FEV1/FVC < 70%
- FEV1/FVC <30% predicted or FEV1< 50% predicted plus chronic respiratory failure
- Classification based on postbronchodilator FEV1
- Respiratory Failure: arterial partial pressure of oxygen PaO2 less than 60mmHg with or without PaCO2 greater than 50mmHg while breathing at sea level
|
Airflow Limitation
COPD is a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. It is clear that this inflammatory process does not respond in the same manner as that with asthma.
The impact of COPD on an individual patient depends not just on the degree of airflow limitation, but also on the severity of symptoms (especially breathlessness and decreased exercise capacity) and complications of the disease. One of the main complications of COPD is depression. Depression in a patient with COPD creates an even more difficult situation to manage.
