Key features to elicit in the history are:

Onset of dyspnoea

Abrupt onset of dyspnoea would be typical of conditions such as pulmonary embolism, anaphylaxis and pneumothorax. This contrasts to the more typically gradual onset of symptoms associated with pneumonia, pulmonary oedema or pleural effusion.

Duration of symptoms

Symptoms are likely to be of a prolonged duration in patients who have COPD, pulmonary oedema (although exacerbations of these conditions may be acute) in contrast to asthma, pneumonia, anaphylaxis or pneumothorax, where presentation to the ED is likely to be early in the course of the illness.

Severity of dyspnoea

Does the dyspnoea occur at rest or only on exercise? If on exercise, what is the patient’s exercise tolerance? This may not be specifically diagnostically useful but will be critical in determining the severity of symptoms and the impact that they are having on activities of daily living. A patient who appears comfortable on the examination trolley may actually be severely limited on simply standing/walking or even just talking.

Precipitating events

A history of trauma will guide the clinician down a different diagnostic pathway compared to a patient with no history of injury. Likewise, a history of allergen exposure or exposure to a family member with infection will be diagnostically helpful.

Associated symptoms

Chest pain is a symptom which often accompanies breathlessness. Description of the character of the chest pain may indicate whether the presentation is due to an acute coronary syndrome (cardiac ischaemic pain), pneumonia or pneumothorax (pleuritic pain), or a pulmonary embolus (atypical or pleuritic pain). Chest pain and breathlessness should prompt the ED clinician to consider and rule out aortic dissection as a diagnosis.

The presence of a cough with sputum production may indicate infection; haemoptysis may occur with infection or pulmonary infarction (ie. PE). A history of fever would also indicate probable infection. Polydipsia and polyuria may indicate that apparent dyspnoea is due to an underlying metabolic acidosis associated with DKA. The presence of anxiety or stress may point to hyperventilation as the cause.

Postural changes

Is the dyspnoea worse on lying flat? This would indicate that the patient has orthopnoea which is typically associated with pulmonary oedema, and to a lesser extent, with neuromuscular disorders and with COPD.

Past medical history and previous episodes

Past medical history and known/established diagnoses are clearly important: a patient with a known history of myocardial infarction is more likely to have cardiac failure, a patient with known asthma or COPD is likely to present with an exacerbation of bronchospasm. Previous episodes of the same presentation can be helpful (eg. pneumothorax). It is also diagnostically important to establish whether certain risk factors exist (eg for ischaemic heart disease, venous thromboembolic disease, COPD, etc.).

Occupational/social history

Certain respiratory conditions which present with breathlessness are associated with previous occupational or social activities eg. Farmer’s lung, asbestosis, bird fancier’s lung, etc.