Dr Chris Cooper reflects on a variety of possible causes of breathlessness: asthma, atrial fibrillation, COPD, or something else?

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Read this article to learn more about:

  • identifying the cause of breathlessness based on a patient’s symptoms and clinical history
  • key clinical features that help differentiate between conditions where breathlessness is a common symptom
  • appropriate management options following a diagnosis.

Breathing is fundamental to life so any difficulty in breathing is considered a significant risk to health. The primary function of breathing is to provide gas exchange, which often leads clinicians to first consider respiratory problems as possible causes of breathlessness; however, breathing also contributes to acid–base balance and thermoregulation as well as providing the power for functions such as speech and laughter. Clinicians are well advised to consider breathlessness as relevant to many other body systems, particularly cardiovascular health, mental health, and haematological and renal factors.

The IMPRESS algorithm is designed to assist clinicians during the initial assessment of a patient presenting with acute or chronic breathlessness and is intentionally broad-based because of the large number of possible diagnoses.1 These algorithms reflect that a patient may well have more than one condition contributing to the symptom of breathlessness and the existence of terms such as ‘cardiac asthma’ demonstrates that it is very easy to be led astray by symptoms more typical of other causes. Regardless of which condition(s) may be causing breathlessness, it is important to assess general health (including body mass index) and offer support for stopping smoking where relevant. Important aspects to consider during clinical assessment are summarised in Figure 1.

figure 1 important aspects of a clinical assessment of breathlessness

Figure 1 important aspects of a clinical assessment of breathlessness

Case 1

A 28-year-old man attends a same-day appointment reporting sudden-onset breathlessness the previous night. During the consultation, his breathing rate is normal and chest auscultation reveals mild expiratory wheeze. Peak expiratory flow rate (PEFR) is 510 l/min and he says he only attended because his partner told him to. His records show that he has a repeat prescription for salbutamol.


Despite improvement of the patient’s symptoms by the time of presentation, it is likely that he experienced an episode of asthma of unknown severity the previous night. Further questioning, including discussion of a past episode, suggests that this patient’s trigger is exposure to cat hair. It is an important part of asthma care planning for patients to be aware of their individual triggers.2,3

Be aware that the normal ranges for peak flow measurement in younger adults are quite high (depending on age, gender, and height) so it is sensible to calculate PEFR as a percentage of the predicted (or best-ever) reading. For this patient, the reading was somewhat below the expected figure, but the history suggests that the overnight episode may well have met the criteria for a severe exacerbation of acute asthma.

Night-time waking or significant diurnal or day-to-day variability of symptoms should alert the clinician to the possibility of asthma.2 Other important factors when considering the two most common respiratory causes of breathlessness (asthma and chronic obstructive pulmonary disease [COPD]) are shown in Table 1.

Table 1: Clinical features differentiating COPD and asthma4



Smoker or ex-smoker

Nearly all


Symptoms under age 35



Chronic productive cough




Persistent and progressive


Night-time waking with breathlessness and/or wheeze



Significant diurnal or day-to-day variability of symptoms



National Institute for Health and Care Excellence (2010). Chronic obstructive pulmonary disease in over 16s: diagnosis and management. Clinical Guideline 101. Available from: www.nice.org.uk/cg101

NICE has not checked the use of its content in this article to confirm that it accurately reflects the NICE publication from which it is taken.


For this patient, whose symptoms have improved spontaneously, re-prescribing past reliever medication (salbutamol inhaler) alongside an assessment of inhaler technique is likely to cover the immediate episode, provided that no further exposure to the patient’s trigger occurs. However, because of the uncertainty of the severity of the episode overnight, a short course of oral corticosteroid (prednisolone 40–50 mg daily) may also be considered (steroid tablets are as effective as injected steroids, provided they can be swallowed and retained).2 Safety-netting advice should be given in case of recurrence and a plan made for future asthma review in case this episode heralds a change in previously intermittent asthma.

Clinical outcome

This patient responded well to beta2-agonist treatment alone and his symptoms cleared fully within 2 days. Going forward, he made arrangements to avoid contact with his friend’s cat and his medical notes were updated to accurately reflect his condition of allergic asthma.

Case 2

A 66-year-old woman visits the practice complaining of increasing phlegm production with breathlessness, worsening over the past 3 days. She normally only gets breathless if walking uphill, but is now breathless walking on level ground. She managed to quit smoking 2 years ago after previously smoking 10 cigarettes per day for over 50 years. On auscultation there is reduced air entry throughout the chest with a few scattered crackles.


This patient has an infective exacerbation of COPD and there is no clinical suggestion of pneumonia. If basic observations, including pulse and oxygen saturations, are within the normal range it is appropriate to treat the patient in the community.

If the patient has had repeat exacerbations, it would be worth ensuring there is no suggestion of malignancy, using a chest X-ray in the first instance.


In addition to maximising inhaled short-acting bronchodilators (beta2 -agonists, with or without anticholinergics) for this moderate exacerbation of COPD, prescription of a 5–7 day course of both prednisolone 40 mg and an appropriate antibiotic is warranted.5 Interval follow up is important to ensure the patient returns to their usual level of symptoms and allows for assessment of other contributory conditions, such as heart failure, if the patient does not recover to their usual level of function.

Promotion of the influenza vaccine early in the season can help to prevent winter exacerbations and reduce hospital admissions.6

Pulmonary rehabilitation:4

  • should be made available to people with COPD where appropriate, including those who have had a recent hospitalisation for an acute exacerbation
  • should be offered to all patients who consider themselves functionally disabled by COPD (usually modified Medical Research Council [mMRC] scale grade 3 and above)
  • is not suitable for patients who—
    • are unable to walk
    • have unstable angina
    • have had a recent myocardial infarction.

Clinical outcome

This patient responded quickly to treatment over the following 48 hours. Her COPD symptoms, breathlessness, and spirometric measurements returned to their usual levels and remained stable for the subsequent year. She attributes the stability of her symptoms to having succeeded in stopping smoking.

Case 3

At the end of a consultation for a separate unrelated matter, a 71-year-old man mentions that he has been experiencing breathlessness for the last 2 months. He denies any cough, phlegm, tiredness, or weight change. A quick check of his pulse reveals that it is irregularly irregular and the same rate (108 beats per minute [bpm]) as the heartbeat. Heart sounds were normal.


The patient’s irregular pulse suggests that he may have atrial fibrillation. An electrocardiogram (ECG) should be performed for people in whom atrial fibrillation is suspected because an irregular pulse has been detected, to give additional information about the nature and the irregularity of the pulse.7

Consider the reversible causes of atrial fibrillation, such as hyperthyroidism and excessive alcohol intake, as well as being alert to co-existent valvular heart disease in any patient with a cardiovascular abnormality.


Rate control should be offered to people with atrial fibrillation who need drug treatment; either a standard beta-blocker (i.e. a beta-blocker other than sotalol) or a rate-limiting calcium channel blocker should be offered as initial monotherapy.7 Stroke risk should be assessed using CHA2DS2-VASc and anticoagulation should be discussed and initiated where appropriate.7 Patient decision aids are available to assist the patient in making an informed decision about treatment.8 For most people, the benefit of anticoagulation outweighs the risk of bleeding.7

Clinical outcome

The patient’s pulse rate and symptoms responded to a dose of 3.75 mg bisoprolol fumarate and he was referred to the local anticoagulation service. After consideration of the patient’s medical history and his medication preference, warfarin was initiated as, in this case, it was straightforward to retain the international normalised ratio (INR) readings within the therapeutic range.

Case 4

A 35-year-old woman presents 5 days after returning from holiday describing a feeling of needing to use extra effort to breathe, together with a cough. Her notes showed that she had a chest infection 2 years previously. Examination reveals that she is overweight, has a regular pulse of 96 bpm, and normal heart sounds with normal pulse oximetry (95%). Chest auscultation is normal with a respiratory rate of 18 breaths/min and there are no signs of swelling in either leg.


While this patient initially thought that she might have another lung infection, the assessing doctor had suspicions of thromboembolic disease, so referred her to the medical on-call team who confirmed that she had a pulmonary embolism (PE). Both conditions can cause breathlessness, tachypnoea, and tachycardia, but the absence of any other signs of infection and the presence of risk factors for PE should warrant appropriate consideration and further assessment.

Patients with PE do not always have signs of deep vein thrombosis (DVT).9


The two-level PE Wells score can be utilised to estimate the clinical probability of PE. Clinical features, and the associated point scores, are listed below:10,11

  • clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins) [3 points]
  • an alternative diagnosis is less likely than PE [3 points]
  • heart rate >100 beats per minute [1.5 points]
  • immobilisation for more than 3 days or surgery in the previous 4 weeks [1.5 points]
  • previous DVT/PE [1.5 points]
  • haemoptysis [1 point]
  • malignancy (on treatment, treated in the last 6 months, or palliative) [1 point].

A score of >4 points suggests that PE is likely, while a score of ≤4 points suggests that PE is unlikely.

Any patient for whom a diagnosis of PE is likely should be referred for hospital admission.11 If there will be a delay, the clinician should consider interim treatment with low-molecular weight heparin prior to transfer. This is in line with the recommendations in NICE Clinical Guideline 144 that patients in whom a PE is suspected should be offered either an immediate computed tomography pulmonary angiogram (CTPA) or immediate interim parenteral anticoagulant therapy followed by a CTPA, if a CTPA cannot be carried out immediately.11

Clinical outcome

The medical on-call team arranged a CTPA, which confirmed clots in the anterior segmental arteries of both lungs. The patient was commenced on anticoagulation treatment as an inpatient and discharged to community follow up. The patient attributed the full resolution of her symptoms to the prompt referral and treatment process.


Breathlessness is a common symptom,12 encountered in both general practice and emergency departments. Using the available history, examination findings, and objective tests wisely can help the clinician to obtain an accurate diagnosis in the presentation of breathlessness. Sensible interval monitoring to check on improvement can help to ensure that multiple diagnoses contributing to the symptoms are not overlooked. Assessing chronic breathlessness can be complex and may sometimes take more than one assessment to diagnose correctly or completely, especially for rarer causes. Anxiety alone can cause breathlessness but, importantly, most breathlessness of any cause can understandably cause a degree of anxiety for the person experiencing the symptom and therefore a methodical approach to consider each possible cause is advocated.


  1. Improving and Integrating Respiratory Services in the NHS (IMPRESS). Acute breathlessness assessment. The Health Foundation, 2014. Available at: www.networks.nhs.uk/nhs-networks/impress-improving-and-integrating-respiratory/documents/Breathlessness%20algorithm%20IMPRESS%20LSE%20HEalth%20Foundation%20FINAL.pdf
  2. British Thoracic Society (BTS) and the Scottish Intercollegiate Guidelines Network (SIGN). British guideline on the management of asthma. SIGN Guideline 153. SIGN, 2016. Available at: www.brit-thoracic.org.uk/standards-of-care/guidelines/btssign-british-guideline-on-the-management-of-asthma
  3. Asthma UK website. Your asthma action plan. www.asthma.org.uk/advice/manage-your-asthma/action-plan
  4. NICE. Chronic obstructive pulmonary disease in over 16s: diagnosis and management. NICE Clinical Guideline 101. NICE, 2010. Available at: www.nice.org.uk/cg101
  5. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease—2017 report. GOLD, 2016. Available at: www.goldcopd.org/gold-2017-global-strategy-diagnosis-management-prevention-copd/
  6. Poole P, Chacko E, Wood-Baker R, Cates C. Influenza vaccine for patients with chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2006; (1): CD002733.
  7. NICE. Atrial fibrillation: management. NICE Clinical Guideline 180. NICE, 2014. Available at: www.nice.org.uk/cg180
  8. NICE. Atrial fibrillation: medicines to help reduce your risk of a stroke—what are the options? NICE Clinical Guideline 180 tools and resources. NICE, 2014. Available at: www.nice.org.uk/guidance/cg180/resources/cg180-atrial-fibrillation-update-patient-decision-aid-243734797
  9. Stein P, Willis P, DeMets D et al. History and physical examination in acute pulmonary embolism in patients without pre-existing cardiac or pulmonary disease. Am J Cardiol 1981; 47 (2): 218–223.
  10. Wells P, Anderson D, Rodger M et al. Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med 2001; 135 (2): 98–107.
  11. NICE. Venous thromboembolic diseases: diagnosis, management and thrombophilia testing. NICE Clinical Guideline 144. NICE, 2012 (updated November 2015). Available at: www.nice.org.uk/cg144
  12. IMPRESS. Epidemiology of breathlessness—literature review. NHS Networks, 2014. Available at: www.networks.nhs.uk/nhs-networks/impress-improving-and-integrating-respiratory/documents/IMPRESS%20BREATHLESSNESS%20EPIDEMIOLOGY%20LITERATURE%20REVIEW%20summary%20tables%20FINAL.pdf