Distinguishing asthma from COPD
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- Always attempt to make the distinction between asthma and COPD, or determine that both are present, so that the optimal treatment can be prescribed. [√]
- Spirometry is mandatory for detecting airflow limitation in both asthma and COPD. [√]
- The possibilities of both asthma and COPD must be considered in all patients with cough or unexplained breathing difficulty during physical activity. [√]
- Demonstration of a small degree of acute reversibility to bronchodilators alone does not distinguish asthma from COPD. [√]
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Asthma in the elderly is often difficult to distinguish from COPD. Clinical signs of asthma and COPD overlap. Discriminating between asthma and COPD (Table 4), or concluding that both diseases are present and overlapping, is based on the following:
- symptom information
- degree of reversibility of airflow limitation
- peak expiratory flow (PEF) variability
- bronchial hyperresponsiveness
- history of allergy.
Note that:
- single symptoms do not discriminate between asthma and COPD.39
- maximal relevant diagnostic information is obtained when spirometry is performed before and after bronchodilator and before and after a treatment trial.
- the diagnosis might be made with confidence only after observing and collecting clinical data for weeks or months.
For more information, see COPD and asthma.
| Table 4. Factors that distinguish asthma from COPD |
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Factor Present In
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Asthma
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COPD
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Young age at onset
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Often
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Almost never
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Sudden onset of disease
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Often
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Almost never
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| Smoking history |
Sometimes |
Almost always |
| Allergy |
Often |
Sometimes |
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Dyspnoea
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Often |
Often |
| Wheezing |
Often |
Sometimes |
| Coughing |
Sometimes |
Often |
| Sputum production |
Seldom |
Often |
| Chronic airflow limitation |
Seldom |
Almost always |
| Variable airflow limitation |
Almost always |
Seldom |
| Reversible airflow limitation |
Almost always |
Almost never |
| Airway hyperresponsiveness |
Almost always |
Sometimes |
| Diurnal peak expiratory flow variability |
Almost always |
Sometimes |
| Adapted from Van Schayck C, 199640 |
| These factors can help distinguish between asthma and COPD, but be aware that both conditions may be present. |
Content Created (Thursday, 16 November 2006)
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Last Updated ( Thursday, 31 May 2007 )
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