Breathlessness
Exam Tips
- In OSCEs, start with A-E and state explicitly that normal early observations do not exclude life-threatening pathology.
- Orthopnoea and paroxysmal nocturnal dyspnoea strongly point toward left ventricular failure in breathless patients.
- Always ask time course (minutes/hours vs weeks/months): acute onset broadens emergency differentials such as PE, pneumothorax, ACS, and arrhythmia.
- Use focused red flags: chest pain, syncope, haemoptysis, fever, unilateral pleuritic signs, and inability to complete sentences.
- For PE stations, mention Wells score first, then D-dimer only when PE is clinically unlikely and timely testing is available.
- When prescribing oxygen in UK exams, quote target saturations (94-98% or 88-92% if hypercapnia risk) and include safety monitoring.
Definition
Breathlessness (dyspnoea) is a subjective sensation of uncomfortable breathing that occurs when ventilatory demand is perceived to exceed ventilatory capacity. In clinical practice it is classified by time course (acute, subacute, chronic) and should be treated as a syndrome with potentially life-threatening cardiac, pulmonary, metabolic, or neuromuscular causes until proven otherwise.
Pathophysiology
Dyspnoea arises from mismatch between central respiratory drive (cortex/brainstem output) and afferent feedback from chemoreceptors, mechanoreceptors, and respiratory muscles. In cardiovascular disease, elevated left-sided filling pressures cause pulmonary venous congestion and interstitial/alveolar oedema, reducing lung compliance and impairing gas exchange; this increases work of breathing and stimulates J-receptors, producing air hunger and orthopnoea. Reduced cardiac output (for example in heart failure, arrhythmia, or acute coronary syndrome) also causes tissue hypoperfusion and lactic acidosis, further increasing ventilatory drive. See the classic heart failure-pulmonary oedema physiology diagrams in standard UK cardiology chapters (for example Oxford Textbook of Medicine, heart failure section figures).
Risk Factors
- Known heart failure, ischaemic heart disease, valvular disease, or cardiomyopathy
- Older age, hypertension, diabetes mellitus, obesity, chronic kidney disease
- Smoking history and cardiovascular risk profile (dyslipidaemia, family history of premature CVD)
- Previous arrhythmia (especially atrial fibrillation or SVT)
- Recent surgery/immobility or active cancer (raises PE risk)
- Chronic lung disease (COPD, asthma, bronchiectasis, interstitial lung disease)
- Anaemia, thyroid disease, anxiety/hyperventilation tendency
- Drug triggers (for example non-selective beta-blockers in asthma, NSAID-sensitive asthma)
Clinical Features
Symptoms
- Acute or progressive shortness of breath
- Orthopnoea and paroxysmal nocturnal dyspnoea (suggest left heart dysfunction/pulmonary oedema)
- Reduced exercise tolerance, fatigue, difficulty with activities of daily living
- Chest pain, palpitations, presyncope/syncope
- Cough (dry or productive), wheeze, fever, pleuritic pain
- Associated red flags: sudden onset, haemoptysis, collapse, confusion
Signs
- Tachypnoea, use of accessory muscles, inability to speak full sentences
- Hypoxaemia on pulse oximetry (note severe pathology may occur with near-normal saturations early)
- Tachycardia or bradycardia; hypotension or shock in severe cases
- Raised JVP, bilateral basal crackles, peripheral oedema, S3 gallop (heart failure pattern)
- Wheeze/silent chest (asthma severity marker), unilateral reduced breath sounds (possible pneumothorax/effusion)
- Cyanosis, altered mental status, poor peripheral perfusion
Investigations
Management
Lifestyle Modifications
- Stop smoking and avoid second-hand smoke exposure
- Weight optimisation and graded physical conditioning/cardiac rehabilitation where appropriate
- Vaccination optimisation (influenza, pneumococcal in chronic cardiopulmonary disease)
- Fluid/salt moderation and daily weight monitoring in chronic heart failure
- Trigger avoidance in asthma (allergens, cold air, occupational exposures)
- Safety-net advice: seek urgent care for rapidly worsening dyspnoea, chest pain, syncope, or new confusion
Pharmacological Treatment
Emergency oxygen therapy
- Oxygen titrated to SpO2 94-98% (or 88-92% if risk of hypercapnic respiratory failure)
Use controlled oxygen in COPD/hypercapnia risk; monitor gases to avoid oxygen-induced CO2 retention.
Acute cardiogenic pulmonary oedema
- Furosemide 40-80 mg IV slow bolus (higher doses if already on chronic loop diuretic)
- Glyceryl trinitrate 400 micrograms sublingual, repeat every 5 minutes if needed; consider IV GTN infusion starting 10-20 micrograms/min and titrate
Avoid/withhold nitrates in hypotension, severe aortic stenosis, right ventricular infarct, or recent phosphodiesterase-5 inhibitor use. Monitor BP, renal function, and urine output.
Suspected acute coronary syndrome presenting with breathlessness
- Aspirin 300 mg orally once (chewed), unless contraindicated
Check for true aspirin allergy or active major bleeding; continue ACS pathway with serial ECG/troponin and cardiology input.
Regular narrow-complex SVT causing breathlessness
- Adenosine 6 mg rapid IV bolus, then 12 mg if needed, then 12 mg if needed
Contraindicated in severe asthma, second/third-degree AV block (without pacing), and caution with transplant recipients; continuous ECG monitoring required.
Chronic HFrEF disease-modifying therapy (if HF cause confirmed)
- Ramipril 1.25-2.5 mg once daily, titrate to target 10 mg once daily
- Bisoprolol 1.25 mg once daily, titrate to target 10 mg once daily
- Spironolactone 25 mg once daily (up-titrate to 50 mg once daily if indicated)
- Dapagliflozin 10 mg once daily
Initiate and uptitrate with monitoring of BP, heart rate, renal function, and potassium. Avoid ACE inhibitors in pregnancy and history of ACE-inhibitor angioedema; avoid mineralocorticoid antagonists in significant hyperkalaemia.
Asthma/COPD overlap or pulmonary contributors (when present)
- Salbutamol 100-200 micrograms inhaled as needed (or 2.5-5 mg nebulised in acute severe episodes)
- Prednisolone 40 mg orally once daily for 5 days in acute COPD exacerbation
- Ipratropium bromide 500 micrograms nebulised every 6-8 hours in acute obstructive exacerbations
Tailor to confirmed diagnosis; beta-blocker prescribing in asthma requires caution and specialist judgement.
Surgical / Interventional
- Urgent reperfusion (PCI) for ACS where indicated
- Valve intervention (surgical or transcatheter) for significant valvular disease causing heart failure
- Pericardiocentesis for cardiac tamponade
- Catheter ablation for recurrent symptomatic arrhythmia
- Thoracocentesis/chest drain for large pleural effusion or pneumothorax when indicated
Complications
- Acute hypoxic respiratory failure
- Cardiogenic shock and multi-organ dysfunction
- Malignant arrhythmias and sudden cardiac death
- Type 1 or type 2 myocardial infarction
- Renal injury from low perfusion or aggressive diuresis
- Recurrent hospital admission and severe functional decline
Prognosis
Prognosis depends on the underlying aetiology, speed of diagnosis, and burden of comorbidity. Reversible triggers (for example SVT, infection, fluid overload) can improve rapidly with treatment, whereas chronic heart or lung disease often causes recurrent episodes and reduced exercise capacity; persistent breathlessness is associated with higher admission and mortality risk.
Sources & References
✅NICE Guidelines(1)
- Breathlessness[overview]
📖Textbook References(2)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 237, 238)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 238)[context]