Dyspnoea
Dyspnoea is the uncomfortable awareness of breathing.
Causes
Sudden (Seconds to Minutes)
• Anxiety
Figure 15 A pneumothorax, visible on the right side.
Note the absence of lung markings at the periphery. The lung edge is visible (arrow).
Acute (Hours to Days)
Chronic (Months To Years)
History
Many cardiac or respiratory diseases of sufficient severity produce dyspnoea. When considering chronic respiratory causes, you may relate them anatomically to diseases of the pulmonary vasculature, airways, interstitium and chest wall. When approaching a patient with dyspnoea, it is important to ensure that the ABC are attended to before continuing with the diagnostic process.
Onset
The speed of onset is a useful indicator of the disease process. Classification by speed of onset narrows the differential diagnosis in urgent clinical situations.
Precipitating factors
An obvious precipitating factor may be present, such as trauma causing either fractured ribs or a pneumothorax. Aspiration of a foreign body may be determined from the history; however, aspiration of vomit is more difficult, as it usually occurs in patients with decreased consciousness levels or who have lost the gag reflex. Dyspnoea on recumbency is caused by cardiac failure; occasionally patients may complain of waking up at night gasping for breath when they slide down the pillows (paroxysmal nocturnal dyspnoea). Dyspnoea associated with asthma may be seasonal (grass pollen) or perennial (house-dust mite faecal proteins), depending on the precipitating allergen. A history of severe allergy should lead to the consideration of anaphylaxis. Stressful events can precipitate asthma attacks but may also cause anxious patients to hyperventilate.
Relieving factors
Dyspnoea resulting from cardiac failure may be relieved by sitting upright, and, when due to asthma, by beta agonists.
Associated factors
Cough productive of (green, yellow, rusty) sputum indicates the presence of a chest infection. This may be the primary cause or it may exacerbate dyspnoea in patients with an existing condition such as asthma, COPD or cardiac failure. Bloodstained sputum may result from a chest infection (especially TB), pulmonary embolism or a tumour. Wheezing may result from asthma or aspiration of a foreign body.
