5. The common component of COPD is airflow obstruction Chronic bronchitis Emphysema Airflow obstruction Asthma
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9. GOLD guidelines outline key points in COPD diagnosis Chronic cough Present intermittently or every day Often present throughout the day; seldom only nocturnal Chronic sputum production Any pattern of chronic sputum production may indicate COPD Dyspnoea that is: Progressive (worsens over time) Persistent (present every day) Described by the patient as an ‘increased effort to breathe’, or ‘gasping’ Worse during exercise Worse during respiratory infections History of exposure to risk factors, especially: Tobacco smoke Occupational dusts and chemicals Smoke from home cooking and heating fuels Pauwels RA, et al. Am J Respir Crit Care Med 2001
10. GOLD guidelines: Classification of severity of COPD 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 /FVC <70% - 30% FEV 1 <80% predicted (IIA: 50% FEV 1 <80% predicted, IIB: 30% FEV 1 <50% predicted) - With or without chronic symptoms (cough, sputum production, dyspnoea) III: Severe COPD - FEV 1 /FVC <70% - FEV 1 <30% predicted or FEV 1 <50% predicted plus respiratory failure or clinical signs of right heart failure
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13. Increase in Asthma Prevalence with Time 1982 1988 1992 1968 1982 1979 1984 1989 1975 1973 1971-74 1976-80 Source: Global Initiative for Asthma NHLBI/WHO Workshop Report 1996 *Diagnosed asthma: asthma diagnosed at any time. Asthma and/or wheeze.
24. Chest X-rays do not have a pivotal role in diagnosis of COPD Hyperinflated lungs severe COPD Normal X-ray mild COPD
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26. Subdivisions of the total capacity of the lungs Total lung capacity Full inspiration Full expiration Tidal volume Residual volume Maximum forced inspiration Maximum forced expiration FVC
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Editor's Notes
COPD is often a mixture of conditions that have airflow obstruction as the common element. It is not unusual for a patient to present with three diagnoses – emphysema, chronic bronchitis and asthma, all of which have an element of poorly reversible airflow obstruction: such an individual would be classed as having COPD. Conversely, a patient may have simple emphysema or simple bronchitis with no airflow obstruction, and these individuals would not be classed as having COPD. Most cases of asthma have completely reversible airflow obstruction and on this basis can be differentially diagnosed from COPD. 1.2.5
There are several other risk factors that play a role in COPD development but they are all minor compared with cigarette smoking. Occupational job exposure to hazardous airborne substances can increase the risk of COPD, especially in individuals who already smoke. Air pollution may cause respiratory symptoms but is unlikely to cause lung function deficiency. Hyperresponsive airways may play a role in the development of COPD and are not necessarily the result of allergy or atopy. The role of viral infections of the respiratory tract in the development of COPD are not clearly established. However, once COPD is established any respiratory infection will accelerate lung function decline. Less than 1% of COPD is thought to be due to AAT deficiency. 1.4.6
In more advanced disease, the patient may show other characteristic signs of the illness. Cyanosis (bluish discolouration of skin and mucous membranes) may be present at rest or during mild exercise. An enlarged liver and distension of the veins in the neck are suggestive of cor pulmonale or heart failure. Anorexia and weight loss are not unusual and there may be evidence of an abnormal decrease in the amount of oxygen in the blood – hypoxaemia, and/or an abnormal increase in the amount of carbon dioxide in the blood – hypercapnia. Patients with end-stage disease typically adopt postures that relieve dyspnoea such as leaning forward while standing or sitting with their arms positioned forward on their knees. Exhalation often occurs through pursed lips which prevents collapse of the airways and provides some alleviation of discomfort. 2.1.2
The main diagnostic measures of COPD are agreed by all guideline documents and include: history taking, symptomatic assessment, physical examination and spirometric measurements of lung function. 3.0.3
The GOLD guidelines recommend that spirometry should be performed if any of the key indicators (chronic cough, sputum production, dyspnoea, patient history of exposure to risk factors) are present. These indicators are not diagnostic on their own but the presence of several of them increases the probability of a diagnosis of COPD. Spirometry is considered to be essential for establishing a diagnosis of COPD. The GOLD guidelines recommend that the most sensitive test is the FEV 1 /FVC ratio. A post-bronchodilator FEV 1 of 80% of the predicted value in combination with an FEV 1 /FVC of <70% is thought to confirm the diagnosis of COPD. 3.0.6
The GOLD guidelines classify disease severity into 4 stages: ‘At risk’ (0), ‘Mild COPD’ (I), ‘Moderate COPD’ (II) and ‘Severe COPD’ (III). The staging of COPD is based on airflow limitation as measured by spirometry, which is essential for diagnosis and provides a useful description of the severity of pathological changes in COPD. 3.0.7
Deaths in the developed world ~ 45,000 [death rate ~ 5 per 100,000 patients]
In mild COPD the chest X-ray may be normal. As the disease advances, hyperinflation of the chest is evident as larger lung volume, a low flat diaphragm, a thin heart shadow, a marginally increased heart size and an enlarged retrosternal air space on the lateral view. 2.1.3
Two spirometric measurements are the most frequently used: FEV 1 and FVC, although IVC or IC (inspiratory capacity) is thought to be increasingly important. PEF can be measured using both a spirometer and peak flow meter. Measurement of FEV 1 , PEF and FVC alone is not enough to diagnose early-stage COPD. 2.2.1
The spirometer can measure several different lung capacities that make up the total lung capacity. Usually the patient is asked to undergo a ‘forced’ measurement against time – FEV 1 is the most typically used and this measures the maximum forced expiration in one second. The tidal volume shows the volume of air in the lungs during ‘tidal breathing’ – the usual shallow breathing during rest. 2.2.2
FEV 1 is generally the most useful test to assess severity and progression of COPD, although the ratio between FEV 1 and FVC is the most sensitive measure of early airflow obstruction as it is always below the usual adult value of approximately 80%. FEV 1 reduces as the disease progresses. FEF can also be used and reflects small airway function. It is markedly reduced in patients with COPD but has greater variability than FEV 1 and so is not valuable for routine monitoring. PEF can give a crude estimate of lung function. It is not useful for diagnosing COPD since PEF can be relatively well preserved in the early stages of disease. IVC (IC) is becoming an important lung function measurement in the assessment of COPD because patients tend to have more problems during inspiration than during expiration. 2.2.3
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