Upper airway

Questions related to the ear, nose and throat are relevant. Rhinosinusitis often coexists with asthma or, less commonly, bronchiectasis, and can be an aggravating factor. A common cause of chronic cough is postnasal drip secondary to rhinitis. A change in the voice may indicate involvement of the left recurrent laryngeal nerve by a carcinoma of the lung. Sometimes patients using inhaled corticosteroids for asthma develop oropharyngeal candidiasis or even hoarseness or weakness of the voice, which improves on changing the treatment. Do not ascribe hoarseness to this cause in older patients, as carcinoma of the vocal cords can also be present with hoarseness or a change in the quality of the voice. Laryngoscopy is always indicated if hoarseness persists for more than 4 weeks.

The smoking history

Always take a full smoking history. Do so in a sympathetic and non-judgemental way, or the detail is unlikely to be accurate. The time for advice about smoking cessation is after completion of your assessment, not at the outset. Simply asking ‘Do you smoke?’ is not enough. Novices will be astonished at how often closer probing of the answer ‘no’ reveals that the patient gave up yesterday, or that he states his intention of doing so from the time of your consultation. Age of starting and stopping if an ex-smoker, and average consumption for both current and ex-smokers, are the bare minimum information needed.

Identification of an individual as a current or ex-smoker will greatly influence the interpretation you place on your findings upon history and examination. Almost all cases of lung cancer and chronic obstructive pulmonary disease (COPD) occur in those who have smoked.

The family history

There is a strong inherited susceptibility to asthma. Associated atopic conditions such as eczema and hay fever may also be present in relatives of those with asthma, particularly in those who develop the condition when young.

The occupational history

No other organ is as susceptible to the working environment as the lungs. Several hundred different substances have now been recognized as causing occupational asthma. Paint sprayers, workers in the electronics, rubber or plastics industries and woodworkers are relatively commonly affected. Always ask about a relationship between symptoms and work.

Damage from inhalation of asbestos may take decades to become manifest, most seriously as malignant mesothelioma. In industrialized countries, this once extremely rare tumour of the pleura has become more common, and will become even more common in the next 20 years. In middle-aged individuals who present with a pleural effusion, often the first sign of a mesothelioma, always ask about possible asbestos exposure in jobs right back to the time of first employment.

Hands

The hands should be inspected for clubbing, pallor or cyanosis. Respiratory causes of clubbing include carcinoma of the bronchus, pulmonary fibrosis, bronchiectasis, lung abscess and pleural empyema. A fine tremor may indicate the use of inhaled β₂ agonists, such as salbutamol. A flap may indicate carbon dioxide retention or hypercapnia. Such patients are often drowsy, with warm hands and a bounding pulse. In a significant asthma attack, the pulse rate is usually raised. The systolic blood pressure also falls during the severe inspiratory effort of acute asthma, and the degree of this fall (the degree of pulsus paradoxus) can be used as a measure of asthma severity.

Respiratory rate and rhythm

The respiratory rate and pattern of respiration should be noted. The normal rate of respiration in a relaxed adult is about 14-16 breaths per minute (Box 10.2). Tachypnoea is an increased respiratory rate observed by the doctor, whereas dyspnoea is the symptom of breathlessness experienced by the patient. Apnoea means cessation of respiration.

Cheyne-Stokes breathing is the name given to a disturbance of respiratory rhythm in which there is cyclical deepening and quickening of respiration, followed by diminishing respiratory effort and rate, sometimes associated with a short period of complete apnoea, the cycle then being repeated. This is often observed in severely ill patients, and particularly in severe cardiac failure, narcotic drug poisoning and neurological disorders. It is occasionally seen, especially during sleep, in elderly patients without any obvious serious disease.

Some patients may have apnoeic episodes during sleep owing to complete cessation of respiratory effort (central apnoea) or, much more commonly, apnoea despite continuation of respiratory effort. This is known as obstructive sleep apnoea, is due to obstruction of the upper airways by soft tissues in the region of the pharynx and is commoner in obese patients.

Venous pulses

The venous pulses in the neck (see Ch. 11) should be inspected. A raised jugular venous pressure (JVP) may be a sign of cor pulmonale, right heart failure caused by chronic pulmonary hypertension in severe lung disease, commonly COPD. Pitting oedema of the ankles and sacrum is usually present. However, engorged neck veins can be due to superior vena cava obstruction (SVCO), usually because of malignancy in the upper mediastinum. SVCO can also be associated with facial swelling and plethora (redness).

Head

Examination of the eyes may reveal anaemia or, rarely, Horner’s syndrome, secondary to a cancer at the lung apex (Pancoast tumour) invading the cervical sympathetic chain. The lips and tongue should be inspected for central cyanosis, which almost always indicates poor oxygenation of the blood by the lungs, whereas peripheral cyanosis alone is usually due to poor peripheral perfusion. Oral candida may indicate use of inhaled steroids or be a sign of debilitation or underlying immune suppression in the patient.

Relevant anatomy

The interpretation of signs in the chest often causes problems for the beginner. A revision of the relevant anatomy may help.

The bifurcation of the trachea corresponds on the anterior chest wall with the sternal angle, the transverse bony ridge at the junction of the body of the sternum and the manubrium sterni. Posteriorly, the level is at the disc between the fourth and fifth thoracic vertebrae. The ribs are most easily counted downwards from the second costal cartilage, which articulates with the sternum at the extremity of the sternal angle.

A line from the second thoracic spine to the sixth rib, in line with the nipple, corresponds to the upper border of the lower lobe (oblique or major interlobar fissure). On the right side, a horizontal line from the sternum at the level of the fourth costal cartilage, drawn to meet the line of the major interlobar fissure, marks the boundary between the upper and middle lobes (the horizontal or minor interlobar fissure). The greater part of each lung, as seen from behind, is composed of the lower lobe; only the apex belongs to the upper lobe. The middle and upper lobes on the right side and the upper lobe on the left occupy most of the area in front (Fig. 10.2). This is most easily visualized if the lobes are thought of as two wedges fitting together, not as two cubes piled one on top of the other (Fig. 10.3).

Figure 10.2 Anterior and posterior aspects of the lungs.

Figure 10.3 Lateral aspect of the left lung.

The stethoscope is so much part of the ‘image’ of a doctor that it is very easy for the student to forget that listening is only one part of the examination of the chest. Obtaining the maximum possible information from your examination requires you to look, then to feel and, only then, to listen.

Looking: inspection of the chest

Appearance of the chest

First, look for any obvious scars from previous surgery. Thoracotomy scars (from lobectomy or pneumonectomy (removal of the whole lung)) are usually visible running from below the scapula posteriorly, sweeping round the axilla to the anterior chest wall. Pleural procedures such as intercostal drain insertion or biopsy may be associated with small scars, often in the axilla or posteriorly. A small scar above the sternal notch indicates a previous tracheostomy. Look for any lumps visible beneath the skin, or any lesions on the skin itself.

Next, inspect the shape of the chest itself. The normal chest is bilaterally symmetrical and elliptical in cross-section, with the narrower diameter being anteroposterior. The chest may be distorted by disease of the ribs or spinal vertebrae, as well as by underlying lung disease (Box 10.3).

Box 10.3 Features to note in assessing the shape of the chest

Kyphosis

Scoliosis

Flattening

Overinflation

Kyphosis (forward bending) or scoliosis (lateral bending) of the vertebral column will lead to asymmetry of the chest and, if severe, may significantly restrict lung movement. A normal chest X-ray is seen in Figure 10.4. Severe airways obstruction, particularly long-term as in COPD (Fig. 10.5), may lead to overinflated lungs. On examination, the chest may be ‘barrel shaped’, most easily appreciated as an increased anteroposterior diameter, making the cross-section more circular. On X-ray, the hemidiaphragms appear lower than usual, and flattened.

Figure 10.4 Normal chest X-ray.

Figure 10.5 Chest X-ray in severe chronic obstructive pulmonary disease.

Feeling: palpation of the chest

Feeling: percussion of the chest

The technique of percussion was probably developed as a way of ascertaining how much fluid remained in barrels of wine or other liquids. Auenbrugger applied percussion to the chest having learned this method in his father’s wine cellar. Effective percussion is a knack that requires consistent practice; do so upon yourself or on willing colleagues, as percussion can be uncomfortable for patients if performed repeatedly and inexpertly.

The middle finger of the left hand is placed on the part to be percussed and pressed firmly against it, with slight hyperextension of the distal interphalangeal joint. The back of this joint is then struck with the tip of the middle finger of the right hand (vice versa if you are left-handed). The movement should be at the wrist rather than at the elbow. The percussing finger is bent so that its terminal phalanx is at right angles and it strikes the other finger perpendicularly. As soon as the blow has been given, the striking finger is raised: the action is a tapping movement.

The two most common mistakes made by the beginner are, first, failing to ensure that the finger of the left hand is applied flatly and firmly to the chest wall and, second, striking the percussion blow from the elbow rather than from the wrist. The character of the sound produced varies both qualitatively and quantitatively (Box 10.6). When the air in a cavity of sufficient size and appropriate shape is set vibrating, a resonant sound is produced, and there is also a characteristic sensation felt by the finger placed on the chest. Try tapping a hollow cupboard and then a solid wall. The feeling is different as well as the sound. The sound and feel of resonance over a healthy lung has to be learned by practice, and it is against this standard that possible abnormalities of percussion must be judged.

The normal degree of resonance varies between individuals, and in different parts of the chest in the same individual, being most resonant below the clavicles anteriorly and the scapulae posteriorly where the muscles are relatively thin, and least resonant over the scapulae. On the right side, there is loss of resonance inferiorly as the liver is encountered. On the left side, the lower border overlaps the stomach, so there is a transition from lung resonance to tympanitic stomach resonance.

Always systematically compare the percussion note on the two sides of the chest, moving backwards and forwards from one side to the other, not all the way down one side and then down the other. Percuss over the clavicles; traditionally, this is done without an intervening finger on the chest, but there is no reason for this and it is more comfortable for the patient if the finger of the left hand is used in the usual way. Percuss three or four areas on the anterior chest wall, comparing left with right. Percuss the axillae, then three or four areas on the back of the chest.

Reduction of resonance (i.e. the percussion note is said to be dull) occurs in two important circumstances:

Less commonly, a dull percussion note may be due to thickened pleura. The percussion note is most dull when there is underlying fluid, as in a pleural effusion. Pleural effusion causes the sensation in the percussed finger to be similar to that felt when a solid wall is percussed. This is often called ‘stony dullness’. By comparing side with side, it is usually easy to detect a unilateral pleural effusion. Pleural effusion usually leads to decreased chest wall movement. Effusions may occur bilaterally in some patients, and this may be more difficult to detect clinically.

An increase in resonance, or hyperresonance, is more difficult to detect than dullness, and there is no absolute level of normal percussion against which extra resonance can be judged. It may be noticeable when the pleural cavity contains air, as in pneumothorax. Sometimes, however, in this situation one is tempted to think that the slightly duller side is the abnormal side. Further examination and chest X-ray will reveal the true situation.

Listening: auscultation of the chest

Listen to the chest with the diaphragm, not the bell, of the stethoscope (chest sounds are relatively high pitched, and therefore the diaphragm is more sensitive than the bell). Ask the patient to take deep breaths in and out through the mouth. Demonstrate what you would like the patient to do, and then check visually that he is doing it while you listen to the chest. If the patient has a tendency to cough, ask him to breathe more deeply than usual, but not so much as to induce a cough with each breath. As with percussion, you should listen in comparable positions to each side alternately, switching back and forth from one side to the other to compare (Box 10.7).

At the bedside

Hospital inpatients should have a sputum pot which must be inspected (Box 10.8). Mucoid sputum is characteristic in patients with chronic bronchitis when there is no active infection. It is clear and sticky and not necessarily produced in a large volume. Sputum may become mucopurulent or purulent when bacterial infection is present in patients with bronchitis, pneumonia, bronchiectasis or a lung abscess. In these last two conditions, the quantities may be large and the sputum is often foul smelling.

Occasionally asthmatics have a yellow tinge to the sputum, owing to the presence of many eosinophils. A particularly tenacious form of mucoid sputum may also be produced by people with asthma, and sometimes they cough up casts of the bronchial tree, particularly after an attack. Patients with bronchopulmonary aspergillosis may bring up black sputum or sputum with black parts in it, which is the fungal element of the Aspergillus.

When sputum is particularly foul smelling, the presence of anaerobic organisms should be suspected. Pink or white frothy sputum may be brought up by very ill patients with pulmonary oedema. Rusty-coloured sputum is characteristic of pneumococcal lobar pneumonia. Blood may be coughed up alone, or bloodstained sputum produced, with bronchogenic carcinoma, pulmonary tuberculosis, pulmonary embolism, bronchiectasis or pulmonary hypertension (e.g. with mitral stenosis) being possible causes.

In the laboratory

Sputum may be examined under the microscope in the laboratory for the presence of pus cells and organisms, and may be cultured in an attempt to identify the causative agent of an infection and antibiotic resistance patterns. It is seldom practical to wait for the results of such examinations, and most clinical decisions have to be based on the clinical probability of a particular infection being present.

Tuberculosis, a disease that is becoming more common in all parts of the world, requires specialized techniques of laboratory microscopy and culture to identify the responsible organisms, and if the diagnosis is suspected, these tests must be specifically requested.

The chest X-ray

The chest X-ray is an important extension of the clinical examination (Box 10.9). This is particularly so in patients with respiratory symptoms, and a normal X-ray taken some time before the development of symptoms should therefore not be accepted as a reason for not taking an up-to-date film. In many instances, it is of great value to have previous X-rays for comparison, but if these are lacking then careful follow up with subsequent films may provide the necessary information.

The standard chest X-ray is a posteroanterior (PA) view taken with the film against the front of the patient’s chest and the X-ray source 2 m behind the patient (see Fig. 10.4). The X-ray is examined systematically on a viewing box or computer screen, according to the following plan and referring to the thoracic anatomy described at the beginning of this chapter.

The bony skeleton

Is the chest symmetrical?

Is scoliosis present?

Are the ribs unduly crowded or widely spaced in any area?

Are cervical ribs present?

Are any ribs eroded or absent?

As well as the standard AP view, lateral views are sometimes carried out to help localize any lesion that is seen. In examining a lateral view, as in Figure 10.8, follow this plan:

Identify the sternum anteriorly and the vertebral bodies posteriorly. The cardiac shadow lies anteriorly and inferiorly.

There should be a lucent (dark) area retrosternally which has approximately the same density as the area posterior to the heart and anterior to the vertebral bodies. Check for any difference between the two, or for any discrete lesion in either area.

Check for any collapsed vertebrae.

The lowest vertebrae should appear darkest, becoming whiter as they progress superiorly. Interruption of this smooth gradation suggests an abnormality overlying the vertebral bodies involved.

Figure 10.8 A lateral chest X-ray.

The computed tomography scan

The routine chest X-ray consists of shadows at all depths in the chest superimposed on one another. In computed tomography (CT) scanning, X-rays are passed through the body at different angles and the resulting information is processed by computer to generate a series of cross-sectional images. A thoracic CT scan thus comprises a series of cross-sectional ‘slices’ through the thorax at various levels.

The CT scan is a vital part of the staging of lung cancer, and inoperability may be demonstrated by evidence on CT of mediastinal involvement. CT scanning will demonstrate the presence of dilated and distorted bronchi, as in bronchiectasis. Diffuse pulmonary fibrosis will be shown by a modified high-resolution/thin-section scan technique. Emboli in the pulmonary arteries can be demonstrated by a rapid data acquisition spiral CT technique, and has advantages over isotope lung scanning (see below) in diagnosing pulmonary embolism in patients with pre-existing lung disease. Many scanners can now generate three-dimensional representations of the thoracic structures (Fig. 10.9).

Figure 10.9 A CT-generated 3D reconstruction demonstrating that the patient has a tracheal stenosis (arrowed).

(Courtesy of Professor R.H. Reznek.)

Radioisotope imaging

In the lungs, the most widely used radioisotope technique is combined ventilation and perfusion scanning, used to aid the diagnosis of pulmonary embolism.

The perfusion scan is performed by injecting intravenously a small dose of macroaggregated human albumin particles labelled with technetium-99m (^99mTc). A gamma-camera image is then built up of the radioactive particles impacted in the pulmonary vasculature; the distribution of perfusion in the lung can then be seen. The ventilation scan is obtained by inhalation of a radioactive gas such as krypton-81m (^81mKr), again using scanning to identify the distribution of the radioactivity.

Blood is usually diverted away from areas of the lung that are unventilated, so a matched defect on both the ventilation and perfusion scans usually indicates parenchymal lung disease. If there are areas of ventilated lung which are not perfused (i.e. an unmatched defect), this is evidence in support of an embolism to the unperfused area. Figure 10.10 shows a ventilation-perfusion isotope scan. The unmatched defects (areas ventilated by the inspired air but not perfused by blood) suggest a high probability of pulmonary embolism.

Figure 10.10 Ventilation/perfusion isotope scan of the lungs. Segmental and subsegmental loss of perfusion (B & D) can be seen with relatively normal ventilation (A & C). The clear punched-out areas in the perfusion (B & D) scans indicate areas of reduced isotope concentration during the perfusion scan. Thus these are areas of reduced blood flow. The ventilation scans show normal aeration of the lungs as depicted by the isotope distribution in the pulmonary airways. These sequences of scans are suggestive of pulmonary embolism because they show impaired perfusion with normal ventilation.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is useful in demonstrating mediastinal abnormalities and can help evaluate invasion of the mediastinum and chest wall by tumour. Apart from the fact that it does not use ionizing radiation, currently it has few other advantages over CT in imaging the thorax. MRI is particularly degraded by movement artefact in imaging the chest, because of the relatively long data acquisition time, but faster scanners are beginning to overcome this drawback.

Ultrasound

Ultrasound reveals much less detail than CT scanning but has the advantages that it does not involve radiation and, as it gives ‘real-time’ images, the operator can visualize what is happening as it happens.

Ultrasound is used for examining diaphragmatic movement. A paralysed hemidiaphragm usually results from damage to the phrenic nerve by a mediastinal tumour. If the patient is asked to make a sudden inspiratory effort, as in sniffing, the non-paralysed side of the diaphragm moves down, so intrathoracic pressure drops, and the paralysed side moves up.

Ultrasound is also valuable in distinguishing pleural thickening from pleural fluid. With real-time imaging, the latter can be seen to move with changes in posture. When such fluid is present, ultrasound may be used to aid placement of a catheter to drain the collection, and also to steer a draining catheter accurately into an intrapulmonary abscess.

Positron emission tomography (PET) scanning

In this technique, a radiolabelled 18-flurodeoxyglucose (FDG) molecule is administered, which is taken up by metabolically active tissues, such as cancers, showing as ‘hot spots’ on the image. It is useful in detecting regional and mediastinal lymphadenopathy and is now widely used to assess suitability for surgery in patients with lung cancer.

Flexible bronchoscopy

Bronchoscopy is an essential tool in the investigation of many forms of respiratory disease. For discrete abnormalities, such as a mass seen on chest X-ray and suspected to be a lung cancer, bronchoscopy is usually indicated to investigate its nature. Under local anaesthesia, the flexible bronchoscope is passed through the nose, pharynx and larynx, down the trachea, and the bronchial tree is then inspected. Figure 10.11 shows a lung cancer seen down the bronchoscope. Flexible biopsy forceps are passed down a channel inside the bronchoscope, and are used to obtain tissue samples for histological examination. Similarly, aspirated bronchial secretions and brushings of any endobronchial abnormality can be sent to the laboratory for cytological examination.

Figure 10.11 A lung cancer, seen down the bronchoscope.

At bronchoscopy, specimens are also taken for microbiological examination in order to determine the nature of any infecting organisms. In diffuse interstitial lung disease, such as sarcoidosis or pulmonary fibrosis, the technique of transbronchial biopsy can be used to obtain small specimens of lung parenchyma for histological examination to help confirm the diagnosis.

Pleural aspiration and biopsy

A pleural effusion can give rise to diagnostic problems and, sometimes, management problems when the amount of fluid causes respiratory embarrassment. When a pleural effusion is seen as a presenting feature in a middle-aged or older patient, the most likely cause is a malignancy. Less commonly, particularly in younger patients, it may be due to tuberculosis. In either case, the diagnosis is best obtained by both aspiration of the fluid and pleural biopsy. Aspiration alone has a lower diagnostic yield.

After anaesthetizing the skin, subcutaneous tissues and pleura, pleural fluid may be aspirated by syringe and needle for microbiological and cytological examination. Large pleural effusions may need to be drained by an indwelling catheter, left in situ until the fluid has been fully removed. As noted above, ultrasound guidance can be helpful, particularly if the fluid is loculated in various pockets.

Cytological examination of pleural fluid may demonstrate the presence of malignant cells. Many polymorphs may be seen if the effusion is secondary to an underlying pneumonic infection. With tuberculosis, the fluid usually contains many lymphocytes, although tubercle bacilli are rarely seen. Therefore, almost all pleural fluid samples should be cultured for possible tuberculosis, because this infection can coexist with other pathologies and it is so important not to miss it. In empyema, pus is present in the pleural cavity. It has a characteristic appearance and is full of white cells and organisms.

The pleural fluid should also be examined for protein content. A transudate (resulting from cardiac or renal failure) can be distinguished from an exudate (from pleural inflammation or malignancy) by its lower protein content (<30 g/l). Light’s criteria may also be applied (Box 10.10).

Biopsies of the pleura can be obtained percutaneously and under local anaesthesia using an Abram’s pleural biopsy needle. This technique can be used when there is pleural fluid present to obtain pleural tissue for histological examination and, whenever tuberculosis is a possibility, for microbiological culture. If ultrasound or CT examination shows the pleura to be thickened, biopsies may be obtained under image guidance by Abram’s needle, a Tru-cut needle and similar techniques.

Thoracoscopy

This technique enables the pleural cavity to be examined directly and biopsies taken under direct vision. The procedure is commonly performed under a general anaesthetic by a surgeon who uses a rigid thoracoscope after the lung has been deflated. Increasingly, however, more minimally invasive procedures using flexible thoracoscopes attached to cameras are being used (video-assisted thoracoscopic surgery or VATS).

Lung biopsy

As noted above, the technique of transbronchial biopsy can be used to obtain samples of lung parenchyma, but often samples are too small for diagnosis. In this circumstance, biopsies of the lung taken at thoracoscopy may be of value. Occasionally, a formal open lung biopsy obtained at thoracotomy may be necessary.

When there is a discrete, localized lesion, it may be possible to obtain a biopsy percutaneously with the aid of CT scanning to direct the insertion of the biopsy needle (Fig. 10.12).

Figure 10.12 A CT-guided percutaneous biopsy in progress. The radio-dense (white) structure penetrating the chest wall is the biopsy needle.

Immunological tests

Asthma attacks may be due to type I immediate hypersensitivity reactions on exposure to common environmental proteins known as allergens. In such individuals, an inherited tendency to produce exaggerated levels of immunogobulin E (IgE) against these allergens is responsible. Part of the assessment of such allergic patients might include skin-prick tests (see Ch. 15). Alternatively, serum levels of specific (individual) IgEs against allergens may be measured by blood tests (formerly known as RAST tests) to demonstrate sensitization. The total IgE level is often raised in patients with asthma, rhinitis or eczema. Delayed (type IV, cell-mediated) hypersensitivity is shown by the Mantoux and Heaf skin tests, used to detect the presence of sensitivity to tuberculin protein. Precipitating immunoglobulin G (IgG) antibodies in the circulating blood are present in patients with some fungal diseases, such as bronchopulmonary aspergillosis or aspergilloma. In patients suspected of having an allergic alveolitis, IgG antibodies may be demonstrated to the relevant antigens.