Respiratory system

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10 Respiratory system

F. Runa Ali, John C. Moore-Gillon

Introduction

Diseases of the respiratory system account for up to a third of deaths in most countries and for a major proportion of visits to the doctor and time away from work or school. As with every aspect of diagnosis in medicine, the key to success is a clear and carefully recorded history; symptoms may be trivial or extremely distressing, but either may indicate serious and life-threatening disease.

The history

Most patients with respiratory disease will present with breathlessness, cough, excess sputum, haemoptysis, wheeze or chest pain.

Breathlessness

Everyone becomes breathless on strenuous exertion. Breathlessness inappropriate to the level of physical exertion, or even occurring at rest, is called dyspnoea. Its mechanisms are complex and not fully understood. It is not due simply to a lowered blood oxygen tension (hypoxia) or to a raised blood carbon dioxide tension (hypercapnia), although these may play a significant part. People with cardiac disease (see Ch. 11) and even non-cardiorespiratory conditions such as anaemia, thyrotoxicosis or metabolic acidosis may become dyspnoeic as well as those with primarily respiratory problems.

An important assessment is whether the dyspnoea is related only to exertion and how far the patient can walk at a normal pace on the level (exercise tolerance). This may take some skill to elicit, as few people note their symptoms in this form, but a brief discussion about what they can do in their daily lives usually gives a good estimate of their mobility.

Other clarifications will include whether there is variability in the symptoms, whether there are good days and bad days and, very importantly, whether there are any times of day or night that are usually worse than others. Variable airways obstruction due to asthma is very often worse at night and in the early morning. By contrast, people with predominantly irreversible airways obstruction due to chronic obstructive pulmonary disease (COPD) will often say that as long as they are sitting in bed, they feel quite normal; it is exercise that troubles them.

Cough

A cough may be dry or it may be productive of sputum.

How long has the cough been present? A cough lasting a few days following a cold has less significance than one lasting several weeks in a middle-aged smoker, which may be the first sign of a malignancy.

Is the cough worse at any time of day or night? A dry cough at night may be an early symptom of asthma, as may a cough that comes in spasms lasting several minutes.

Is the cough aggravated by anything, for example allergic triggers such as dust, animals or pollen, or non-specific triggers like exercise or cold air? The increased reactivity of the airways seen in asthma, and in some normal people for several weeks after viral respiratory infections, may present in this way. Severe coughing, whatever its cause, may be followed by vomiting.

Sputum

Is sputum produced?

What does it look like? Children and some adults swallow sputum, but it is always worth asking for a description of its colour and consistency. Yellow or green sputum is usually purulent. People with asthma may produce small amounts of very thick or jelly-like sputum, sometimes in the shape of a cast of the airways. Eosinophils may accumulate in the sputum in asthma, causing a purulent appearance even when no infection is present.

How much is produced? When severe lung damage in infancy and childhood was common, bronchiectasis was often found in adults. The amount of sputum produced daily often exceeded a cupful. Bronchiectasis is now rare, and chronic bronchitis causes the production of smaller amounts of sputum.

Haemoptysis

Haemoptysis means the coughing up of blood in the sputum. It should never be dismissed without very careful evaluation of the patient. The potentially serious significance of blood in the sputum is well known, and fear often leads patients not to mention it: a specific question is always necessary, as well as an attempt to decide if it is fresh or altered blood, how much is produced, when it started and how often it happens.

Blood may be coughed up alone, or sputum may be bloodstained. It is sometimes difficult for the patient to describe whether or not the blood has originated from the chest or whether it comes from the gums or nose, or even from the stomach. They should always be asked about associated conditions such as epistaxis (nose bleeds), or the subsequent development of melaena (altered blood in the stool), which occurs in the case of upper gastrointestinal bleeding. Usually, however, it is clear that the blood originates from the chest, and this is an indication for further investigation.

Wheezing

Always ask whether the patient hears any noises coming from the chest. Even if a wheeze is not present when you examine the patient, it is useful to know that he has noticed it on occasions. Sometimes, wheezing will have been noticed by others (especially by a partner at night, when asthma is worse) but not by the patient.

Sometimes stridor (see Ch. 20) may be mistaken for wheezing by both patient and doctor. This serious finding usually indicates narrowing of the larynx, trachea or main bronchi.

Pain in the chest

Apart from musculoskeletal aches and pains consequent upon prolonged bouts of coughing, chest pain caused by lung disease usually arises from the pleura. Pleuritic pain is sharp and stabbing, and is made worse by deep breathing or coughing. It occurs when the pleura is inflamed, most commonly by infection in the underlying lung. More constant pain, unrelated to breathing, may be caused by local invasion of the chest wall by a lung or pleural tumour.

A spontaneous pneumothorax causes pain which is worse on breathing but which may have more of an aching character than the stabbing pain of pleurisy. If a pulmonary embolus causes infarction of the lung, pleurisy and hence pleuritic pain may occur, but an acute pulmonary embolus can also cause pain which is not stabbing in nature. A large pulmonary embolus causing haemodynamic disturbance may cause cardiac-type chest pain.

Other symptoms

Quite apart from the common symptoms of respiratory disease, there are some other aspects of the history that are particularly relevant to the respiratory system.

Upper airway

The examination

An examination of the respiratory system is incomplete without a simultaneous general assessment (Box 10.1). Watch the patient as he comes into the room, during your history taking, and while he is undressing and climbing on to the couch. If this is a hospital inpatient, is there breathlessness just on moving in bed? A breathless patient may be using the accessory muscles of respiration (e.g. sternomastoid) and, in the presence of severe COPD, many patients find it easier to breathe out through pursed lips (Fig. 10.1).

Is there an audible wheeze or stridor?

Is the voice hoarse?

Is the patient capable of producing a normal, explosive cough, or is the voice weak or non-existent even when he is asked to cough?

Is the wheezing audible, usually loudest in expiration, or is there stridor, a high-pitched inspiratory noise?

What is on the bedside table (e.g. inhalers, a peak flow meter, tissues, a sputum pot, an oxygen mask)?

What is the physique and state of general nourishment of the patient?

Figure 10.1 Respiratory failure. The patient is breathless at rest and there is central cyanosis with blueness of the lips and face. The lips are pursed during expiration, a characteristic feature of COPD. This facial appearance is often accompanied by heart failure with peripheral oedema (cor pulmonale).

For the examination, the patient should be resting comfortably on a bed or couch, supported by pillows so that he can lean back comfortably at an angle of 45° (this is often more upright than patients choose for themselves).

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.

Box 10.2 Observing the chest

Rate of respiration

Rhythm of respiration

Chest expansion

Symmetry

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).