Dyspnoea is a common presenting problem and has a very wide differential. It may be due to a single isolated pathology or a combination of problems.
It is important to know what the patient means by SOB and how it is affecting their quality of life. The Medical Research Council dyspnoea scale should be familiar to all clinicians. A systems-based approach may be necessary to establish a differential, for example, cardiac versus respiratory causes.
Key features of the history include the nature of the onset; whether the SOB is related to exertion; cough (is it nocturnal?); expectorate; wheeze; haemoptysis; associated chest pain (is it pleuritic or cardiac?); paroxysmal nocturnal dyspnoea; orthopnoea; peripheral oedema and weight loss, night sweats or appetite loss.
Acute dyspnoea has a number of differentials. Chronic dyspnoea needs to be evaluated carefully and history should focus on any associated respiratory and cardiac symptoms.
A detailed smoking history should be explored and quantified in pack-years.
Other important aspects of the history include exposure to asbestos personally or via a partner's exposure (washing of overalls, for example), pigeon racing and occupation. Is occupational asthma a possibility? Has there been any exposure to coal or other dusts?
Neuromuscular disorders, such as Guillain-Barre syndrome and polio, can involve the respiratory system, thus neurological symptoms may be relevant.
Complete the history and also note medications. Some lung conditions can be caused by medications, for example pulmonary fibrosis due to amiodarone or nitrofurantoin.
Examination should include pulse rate and rhythm, oxygen saturation, evidence of distress while speaking, temperature and BP. Look for evidence of cyanosis - central or peripheral. Look for clubbing, tar-stained hands and raised JVP.
Is there any evidence of chest wall deformity or asymmetrical movement of the chest wall? Auscultate heart sounds, listening for evidence of murmurs or gallop rhythm. Percuss the chest - is there any evidence of hyper-resonance or dullness? Auscultate the chest, paying attention to any focal signs. Look also for peripheral oedema.
Investigations will depend on the history and examination findings but may include:
- Bloods: FBC, U&Es, LFTs, TSH, glucose, D-dimer, brain natriuretic peptide.
- ECG; chest X-ray.
- Peak flow diary.
- Anxiety scores.
Further investigations, such as CT of the chest, or more detailed cardiac investigations, such as myocardial perfusion, scanning and angiogram, will require referral to secondary care.
- Dr Singh is a GP in Northumberland