The diagnosis of COPD poses a particular problem for health care practitioners. This is not surprising because COPD can be a complex diagnosis to make. It is based on history of smoking and industrial exposures, symptoms, lifestyle and co-morbidities, coupled with spirometric, laboratory and radiological findings. The following few pages define COPD and help you to make a confident diagnosis.
What is COPD?
COPD is an obstructive lung disease and is a combination of emphysema and chronic bronchitis in varying proportions predominantly caused by cigarette smoking. The lungs of COPD patients are inflamed and have numerous neutrophils and CD8+ T-lymphocytes within the lung tissue and airways. The lungs may have large areas of destruction, with the presence of large cavities within the airways known as bullae. The term obstructive lung disease means the patient has difficulty breathing out which contributes to hyperinflation and breathlessness.
COPD patients are susceptible to infection within the airway, with colonisation by bacteria. COPD can also manifest itself as a systemic disease (co-morbidity) as the inflammation is not confined to the lung. COPD contributes towards weight loss, muscle weakness, cardiac disease and osteoporosis.
The diagnosis of COPD is suspected on the basis of symptoms and signs and supported by spirometry. Spirometry can be used to assess the severity of airflow limitation and together with other investigations can predict prognosis. The principle differential diagnosis is asthma.
More details can be found in the history taking, spirometry and differentiation between asthma and COPD sections of this site.