Respiratory
Acute breathlessness
Adult with acute or acutely worsened dyspnoea
Time-critical presentation5-stage reasoningCase walk-through
What to ask
Use speed of onset to shortlist, then adherence and trigger history to explain it.- Onset in seconds to minutes: pneumothorax, embolism, anaphylaxis, aspiration.
- Onset over hours to days: infection, asthma or COPD exacerbation, pulmonary oedema.
- Orthopnoea, paroxysmal nocturnal dyspnoea, ankle swelling and weight gain.
- Wheeze, cough, sputum volume and colour, fever, chest pain.
- Known asthma, COPD, heart failure, malignancy; inhaler technique, steroid and diuretic adherence.
- Immobility, recent surgery, long travel, previous thromboembolism, pregnancy.
Discriminators
- Breathlessness that wakes the patient at 3 am with froth suggests pulmonary oedema, not asthma.
- Sudden pain with breathlessness in a tall young man suggests pneumothorax.
- Breathless without wheeze or crackles and with a clear chest points to embolism, anaemia or acidosis.
Case walk-through — SpO2 99% and getting drowsy
4 decisions · moderateCase vignette
A 70-year-old with severe COPD arrives by ambulance on 15 L/min oxygen via a reservoir mask. He is drowsy with a flapping tremor. SpO2 99%, respiratory rate 12/min, pH 7.21, PaCO2 9.4 kPa, PaO2 24 kPa, bicarbonate 32 mmol/L.
- 1
What is the single most important immediate change?
- 2
What drug treatment accompanies the oxygen change?
Answer the previous step to continue.
- 3
After one hour on controlled oxygen and full therapy the gas shows pH 7.24 and PaCO2 8.9 kPa. What now?
Answer the previous step to continue.
- 4
He improves on NIV over 24 hours. What must the discharge package include?
Answer the previous step to continue.
Full checklist
Original structured checklist- 1
History
- Speed of onset — minutes suggests PE, pneumothorax or anaphylaxis; days suggests infection or heart failure
- Orthopnoea and paroxysmal nocturnal dyspnoea; wheeze; sputum volume and colour; fever
- Known asthma, COPD, heart failure, malignancy; inhaler and diuretic adherence
- Immobility, surgery, travel and previous thromboembolism
- 2
Examination
- Respiratory rate, SpO2, work of breathing, ability to speak
- Auscultation: wheeze, crackles, absent sounds; percussion note
- Cardiovascular: JVP, murmurs, gallop, peripheral oedema
- Calves for DVT; peak flow in suspected asthma
- 3
Initial tests
- Blood gas (venous or arterial), ECG, chest radiograph
- FBC, urea and electrolytes, CRP, BNP or NT-proBNP where available
- Peak expiratory flow in asthma; D-dimer only when PE is unlikely by Wells
- Bedside ultrasound for effusion, B-lines, pneumothorax and right ventricular strain
- 4
Differential
- Airway: asthma, COPD, upper airway obstruction
- Parenchymal: pneumonia, pulmonary oedema, ILD, ARDS
- Vascular: pulmonary embolism, pulmonary hypertension
- Pleural: pneumothorax, effusion
- Non-respiratory: anaemia, acidosis (including DKA), sepsis, anxiety
- 5
Immediate treatment
- Titrate oxygen: 94-98% generally, 88-92% in known or suspected CO2 retention
- Asthma or COPD: nebulised bronchodilators plus systemic steroid; consider magnesium and NIV
- Pulmonary oedema: sit up, intravenous loop diuretic, nitrate if hypertensive, consider NIV
- Pneumonia: antibiotics guided by severity score; sepsis bundle if criteria are met
- Tension pneumothorax: immediate needle decompression before imaging
- 6
Follow-up
- Reassess response with objective measures, not impression alone
- Escalate to critical care early for persistent acidosis or exhaustion
- Plan inhaler technique review, rehabilitation referral and vaccination
Related diseases
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