rate is achieved) when the lungs are full. FEF25–75 provides information on the calibre of the small airways, but it can be a rather noisy signal.
2 History taking and examination
History taking
History taking is of paramount importance in the assessment of a patient with respiratory disease. Difficult diagnostic problems are more often solved by a carefully taken history than by laboratory tests. It is also during history taking that the doctor gets to know the patient and their fears and concerns. The relationship of trust thus established forms the basis of the therapeutic partnership.
The doctor should start by asking the patient to describe their symptoms in their own words. Listening to the patient’s account of the symptoms is an active process, in which the doctor is seeking clues to underlying processes, judging which items require further exploration and noting the patient’s attitude and anxieties. By carefully posing questions, the skilled clinician directs the patient to focus on pertinent points, to clarify crucial details and to explore areas of possible importance. History‐taking skills develop with experience and with a greater knowledge of respiratory disease.
It is important to appreciate the differences between symptoms, which are a patient’s subjective description of a change in the body or its functions that might indicate disease; signs, which are abnormal features noted by the doctor on examination; and tests, which are objective measurements undertaken at the bedside or in the diagnostic laboratory. Thus, for example, a patient might complain of pain on breathing, the doctor might elicit tenderness on pressing on the chest and an X‐ray might show a fractured rib.
Symptoms
Table 2.1 lists the main respiratory symptoms that might be encountered in history taking.
Dyspnoea
Dyspnoea (breathlessness) is something everyone understands but no one can satisfactorily define. It is a subjective sensation and thus as much about the mind’s interpretation of the signals it receives from the body as about what’s going on in the lungs. Dyspnoea is an unpleasant sensation, an awareness of breathing that seems inappropriately difficult for the demands that have been placed upon the body. It is not tachypnoea (increased respiratory rate), which is a sign noted by the doctor. For example, an athlete at the end of a modest training run will be tachypnoeic but is unlikely to complain of breathlessness.
In history taking, when attempting to determine the cause of dyspnoea, careful assessment includes taking note of the speed of onset, progression, periodicity and precipitating/relieving factors. The severity of dyspnoea is graded according to the patient’s exercise tolerance (e.g. dyspnoeic on climbing a flight of stairs or at rest). Onset may be sudden, as in the case of a pneumothorax, or gradual and progressive, as in chronic obstructive pulmonary disease (COPD). An episodic dyspnoea pattern is characteristic of asthma, with symptoms typically being precipitated by cold air or exercise and often displaying diurnal variability (varying with the time of day). Orthopnoea is dyspnoea that occurs when lying flat and is relieved by sitting upright. It is a characteristic feature of pulmonary oedema or diaphragm paralysis but can be found in most respiratory diseases if very severe. Paroxysmal nocturnal dyspnoea (PND) is the phenomenon of waking up breathless at night. Most medical students assume this implies pulmonary oedema, but it is also a cardinal feature of asthma. An exploration of other features of these two conditions is needed before a conclusion about cause can be drawn.
Table 2.1 Main respiratory symptoms
| Dyspnoea (Breathlessness)WheezeCoughSputumHaemoptysisChest pain |
It is important to note what words the patient uses to describe the symptoms: ‘tightness in the chest’ may indicate breathlessness or angina. Dyspnoea is not a symptom that is specific to respiratory disease and it may be associated with various cardiac diseases, anxiety, anaemia and metabolic states such as ketoacidosis.
Wheeze
This is a whistling or musical noise that is characteristic of air passing through a narrow tube. The sound of wheeze can be mimicked by breathing out almost to residual volume and then giving a further sharp, forced expiration. Wheeze is a characteristic feature of airway obstruction. It is seen in asthma. In theory, it might be expected in COPD but is rarely found in practice. In COPD, auscultation is more likely to reveal diminished (quiet) breath sounds. It can also occur in pulmonary oedema when airway walls are swollen with fluid. In asthma, wheeze is characteristically worse on waking in the morning and may be precipitated by exercise or cold air. Wheeze that improves at weekends or on holidays away from work and deteriorates on return to the work environment is suggestive of occupational asthma. Wheeze occurs on expiration. ‘Wheeze’ on inspiration is not wheeze, it is stridor – indicating obstruction of the central airways (e.g. obstruction of the trachea by a carcinoma): an important distinction not to miss.
When wheeze is present, airway obstruction is present. Wheeze, however, is not a reliable indicator of obstruction. It is often absent in COPD and severe, life‐threatening asthma may be associated with a ‘silent chest’.
Cough and sputum
Cough begins with closure of the vocal cords; this allows the forced contraction of the abdominal muscles and bracing by the intercostal muscles to generate a large positive pressure within the thorax. Sudden opening of the vocal cords then results in a forceful expiratory blast. The expiratory flow rate produced is much greater than that during voluntary forced expiration; the resultant shearing forces are particularly effective at removing secretions or inhaled solid material. When the vocal cords cannot be opposed, cough is much less effective and its character is quite different (see discussion of bovine cough later in this chapter).
Cough is a protective reflex provoked by physical or chemical stimulation of irritant receptors in the larynx, trachea or bronchial tree. It may be dry or associated with sputum production. The duration and nature of a cough should be assessed, and precipitating and relieving factors should be explored. It is important to examine any sputum produced, noting whether it is mucoid, purulent or bloodstained, for example. Cough occurring on exercise or disturbing sleep at night is a feature of asthma. A transient cough productive of purulent sputum is very common in respiratory tract infections. A weak, ineffective cough that fails to clear secretions from the airways is a feature of bulbar palsy or expiratory muscle weakness, and predisposes the patient to aspiration pneumonia.
Cough is often triggered by the accumulation of sputum in the respiratory tract. Chronic bronchitis is defined as cough productive of sputum on most days for at least 3 months of 2 consecutive years. Bronchiectasis is characterised by the production of copious amounts of purulent sputum. A chronic cough may also be caused by gastro‐oesophageal reflux (with or without aspiration), sinusitis with postnasal drip and, occasionally, drugs (e.g. ACE inhibitors). Violent coughing can generate sufficient force to produce a ‘cough fracture’ of a rib or to impede venous return and cerebral perfusion, causing ‘cough syncope’.
Haemoptysis
Haemoptysis is the coughing up of blood. It is a very important symptom that requires investigation. In particular, it may be the first clue to the presence of bronchial carcinoma. All patients with haemoptysis should have a chest X‐ray performed, and further investigations such as bronchoscopy,