Approach

History

COPD has an insidious onset and usually presents in older people. A history of productive cough, wheezing, and shortness of breath, particularly with exercise, is typical. Other symptoms include frequent bronchitis, reduced exercise tolerance, waking at night with breathlessness, ankle swelling, and fatigue.[1][2]

Patients may complain of fatigue as a result of disrupted sleep secondary to constant nocturnal cough and persistent hypoxia and hypercapnia. The patient's smoking history, occupational exposures, comorbidities, and any family history of lung disease should be determined. A history of previous exacerbations and hospitalisations should be sought.

Patients with COPD may also present with acute, severe shortness of breath, fever, and chest pain during acute infectious exacerbation. See Acute exacerbation of chronic obstructive pulmonary disease.

Physical examination

A physical examination is not diagnostic of COPD but is an important part of patient care.[1] Examination may show tachypnoea, respiratory distress, use of accessory muscles, and intercostal retraction. Barrel chest is a common observation. There may be hyper-resonance on percussion, and distant breath sounds and poor air movement on auscultation. Wheezing, coarse crackles, clubbing, and cyanosis, as well as signs of right-sided heart failure (distended neck veins, loud P2, hepatomegaly, hepatojugular reflux, and lower-extremity oedema), may be present. Occasionally patients may exhibit asterixis - loss of postural control in the outstretched arms (commonly known as a flap) caused by hypercapnia. This is due to impaired gas exchange in lung parenchyma, worsens with exercise, and is suggestive of respiratory failure.

Expiratory wheeze
Expiratory wheeze

Auscultation sounds: Expiratory wheeze

Polyphonic wheeze
Polyphonic wheeze

Auscultation sounds: Polyphonic wheeze

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Early inspiratory crackles
Early inspiratory crackles

Auscultation sounds: Early inspiratory crackles

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Initial tests

Spirometry is required to make the diagnosis of COPD and is also used for monitoring disease progress.[1][2][60]​ It is the most reproducible and objective measure of airflow limitation. Spirometry should be performed after administering an adequate dose of at least one short-acting inhaled bronchodilator to minimise variability.[1] Patients with COPD have a distinctive pattern seen on spirometry, with a reduced FEV₁ and FEV₁/FVC ratio. The presence of airflow limitation is defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria as a post-bronchodilator FEV₁/FVC <0.7.[1] In cases where FVC may be hard to measure, forced expiratory volume at 6 seconds (FEV₆) can be used.[61] Spirometry also indicates the severity of airflow obstruction. In patients with an FEV₁/FVC ratio <0.7:[1]

  • FEV₁ ≥80% predicted indicates mild COPD (GOLD 1)

  • FEV₁ <80% and ≥50% predicted indicates moderate COPD (GOLD 2)

  • FEV₁ <50% and ≥30% predicted indicates severe COPD (GOLD 3)

  • FEV₁ <30% predicted indicates very severe COPD (GOLD 4).

Spirometry in practice
Spirometry in practice

A primary care doctor explains how to perform spirometry and how to avoid any pitfalls.

Spirometry technique and interpretation
Spirometry technique and interpretation

A guide on how to perform and interpret spirometry, including common pitfalls.

Chest x-ray (CXR) is rarely diagnostic but should be performed to exclude other diagnoses and to assess for the presence of significant comorbidities.[1]

Pulse oximetry screens for hypoxia and should be performed in all patients presenting with signs of respiratory failure or right heart failure. If peripheral arterial oxygen saturation is ≤92%, then arterial blood gases should be measured.[1]

In addition to airflow limitation, the GOLD guidelines recognise the importance of exacerbations in affecting the natural course of COPD, and place emphasis on assessment of symptoms, risk factors for exacerbations, and comorbidities.[1]

The Modified British Medical Research Council (mMRC) questionnaire or the COPD Assessment Test (CAT) are recommended to assess symptoms. These can be found in the GOLD guidelines.[1] GOLD cautions against the use of the mMRC dyspnoea scale alone for assessing patients, as symptoms of COPD go beyond dyspnoea alone. For this reason, the CAT is preferred. However, GOLD acknowledges that the use of the mMRC scale is widespread, and so a threshold of an mMRC grade ≥2 is still included to define 'more breathless' patients, as opposed to 'less breathless' patients, in its assessment criteria.[1]

The best predictor of frequent exacerbations (two or more per year) is a history of previously treated exacerbations.[62] In addition, the risk of exacerbations is significantly higher in patients with airflow limitation <50% (severe or very severe COPD).[1]

The GOLD guideline uses a combined 'ABE' approach to assess patients according to their level of symptoms and previous history of exacerbations. Symptoms are assessed using the mMRC or CAT scale. Exacerbations are assessed independently of symptoms to highlight their clinical relevance.[1]

  • Group A: low risk (0-1 exacerbations per year, not requiring hospitalisation) and fewer symptoms (mMRC 0-1 or CAT <10)

  • Group B: low risk (0-1 exacerbations per year, not requiring hospitalisation) and more symptoms (mMRC ≥2 or CAT ≥10)

  • Group E: high risk (≥2 exacerbations per year, or ≥1 requiring hospitalisation) and any level of symptoms.

UK guidelines recommend a full blood count (FBC) for all newly diagnosed patients to screen for anaemia or polycythaemia.[2]

Other tests

Detailed pulmonary function tests performed in specialist pulmonary function laboratories can measure flow volume loops and inspiratory capacity. They are not used routinely but can be helpful in resolving diagnostic uncertainties and for preoperative assessment. Diffusing capacity of the lung for carbon monoxide (DLCO) was previously only measured in specialist laboratories; however, portable systems are now available, allowing measurements to be taken in the field. International guidelines from GOLD recommend a DLCO measurement if a patient with COPD has dyspnoea that is disproportionate to their degree of airflow obstruction. A low DLCO value (<60% predicted) in a patient with COPD is associated with decreased exercise capacity, worse health status, and increased risk of death.[1] Serial peak flow measurements may distinguish COPD from asthma if there is diagnostic uncertainty.[2]

In young patients (<45 years) with a family history or with rapidly progressing disease and lower lobe changes on imaging tests, alpha-1 antitrypsin level should be checked. The World Health Organization (WHO) recommends that all patients with a diagnosis of COPD should be screened once, especially in areas with high prevalence of alpha-1 antitrypsin deficiency.[63] This may aid in family screening and counselling.[1]

Computed tomography (CT) scans show anatomical changes, and their use in COPD is increasing. GOLD guidelines recommend consideration of CT scan for patients with persistent exacerbations, those with symptoms that do not correspond with disease severity on lung function testing, those with FEV₁ <45% of predicted with significant hyperinflation, and those meeting criteria for lung cancer screening.[1] Annual low-dose CT scan (LDCT) is recommended by the US Preventive Services Task Force (USPSTF) for lung cancer screening in patients with COPD that is due to smoking.[64]

Obstructive sleep apnoea is associated with increased risk of death and hospitalisation in patients with COPD, and a sleep study should be considered.[65]

Exercise testing can be useful in patients with a disproportional degree of dyspnoea.[1]​​​​ It can be performed on a cycle or treadmill ergometer, or by a simple timed walking test (e.g., 6 minutes, or duration <6 minutes).[66] Exercise testing is also of use in selecting patients for rehabilitation. Respiratory muscle function may also be tested if dyspnoea or hypercapnia are disproportionately increased with respect to FEV₁, as well as in patients with poor nutrition and those with corticosteroid myopathy.[67]

In patients with frequent exacerbations, severe airflow limitation, and/or exacerbations requiring mechanical ventilation, sputum should be sent for culture.[1]

Risk factors for COPD are similar to those for ischaemic heart disease, so comorbidity is common. ECG may detect right ventricular hypertrophy, arrhythmia, or ischaemia. Echocardiogram evaluates suspected cardiac disease or pulmonary hypertension.[2]

The WHO has specified a minimum set of interventions for the diagnosis of COPD in primary care. WHO: package of essential noncommunicable (PEN) disease interventions for primary health care Opens in new window​​

Presence of high circulatory eosinophils predicts higher risk of exacerbations and predicts good response in preventative and therapeutic effects of corticosteroids. Blood eosinophil counts can identify patients who are more likely to respond to inhaled corticosteroids (ICS).[68][69][70]​​​​ They may predict the effectiveness of adding ICS to regular long-acting bronchodilator treatment to prevent exacerbations.[69][70][71]​​​​​​​ Little or no effect is seen with ICS at blood eosinophil counts of <100 cells/microlitre, while maximal effect is seen at blood eosinophil counts of ≥300 cells/microlitre.[68][72]​​ These thresholds indicate approximate cut-off values that may help clinicians predict the likelihood of ICS treatment benefit.[1] Patients with blood eosinophils ≥300 cells/microlitre are at greatest risk of exacerbations after withdrawing ICS.[73]

Radial artery puncture animated demonstration
Radial artery puncture animated demonstration

How to obtain an arterial blood sample from the radial artery.

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