Chapter 3 The general principles of physical examination
Students beginning their training in physical examination will be surprised at the formal way this examination is taught and performed.1,2 There are, however, a number of reasons for this formal approach. The first is that it ensures the examination is thorough and that important signs are not overlooked because of a haphazard method.3 The second is that the most convenient methods of examining patients in bed, and for particular conditions in various other postures, have evolved with time. By convention, patients are usually examined from the right side of the bed, even though this may be more convenient only for right-handed people. When students learn this, they often feel safer standing on the left side of the bed with their colleagues in tutorial groups, but many tutors are aware of this device, particularly when they notice all students standing as far away from the right side of the bed as possible.
The danger of a systematic approach is that time is not taken to stand back and look at the patient’s general appearance, which may give many clues to the diagnosis. Doctors must be observant, like a detective (Conan Doyle based his character Sherlock Holmes on an outstanding Scottish surgeon).4 Taking the time to make an appraisal of the patient’s general appearance, including the face, hands and body, conveys the impression to the patient (and to the examiners) that the doctor or student is interested in the person as much as the disease. This general appraisal usually occurs at the bedside when patients are in hospital, but for patients seen in the consulting room it should begin as the patient walks into the room and during the history taking, and continue at the start of the physical examination.
Diagnosis has been defined as ‘the crucial process that labels patients and classifies their illnesses, that identifies (and sometimes seals) their likely fates or prognoses and that propels us towards specific treatments in the confidence (often unfounded) that they will do more good than harm’.5
First impressions
First, decide how sick the patient seems to be: that is, does he or she look generally ill or well? The cheerful person sitting up in bed reading Proust (Figure 3.1) is unlikely to require urgent attention to save his life. At the other extreme, the patient on the verge of death may be described as in extremis or moribund. The patient in this case may be lying still in bed and seem unaware of the surroundings. The face may be sunken and expressionless, respiration may be shallow and laboured; at the end of life, respiration often becomes slow and intermittent, with longer and longer pauses between rattling breaths.
Vital signs
Certain important measurements must be made during the assessment of the patient. These relate primarily to cardiac and respiratory function, and include pulse, blood pressure, temperature and respiratory rate. For example, an increasing respiratory rate has been shown to be an accurate predictor of respiratory failure.6 Patients in hospital may have continuous ECG and pulse oximetry monitoring on display on a monitor; these measurements may be considered an extension of the physical examination.
The vital signs must be assessed at once if a patient appears unwell. Patients in hospital have these measurements taken regularly and charted. They provide important basic physiological information.
Facies
A specific diagnosis can sometimes be made by inspecting the face, its appearance giving a clue to the likely diagnosis. Other physical signs must usually be sought to confirm the diagnosis. Some facial characteristics are so typical of certain diseases that they immediately suggest the diagnosis, and are called the diagnostic facies (Table 3.1 and Figure 3.2). Apart from these, there are several other important abnormalities that must be looked for in the face.
| Amiodarone (anti-arrhythmic drug)—deep blue discoloration around malar area and nose |
| Acromegalic (page 307) |
| Cushingoid (page 309) |
| Down syndrome (page 314) |
| Hippocratic (advanced peritonitis)—eyes are sunken, temples collapsed, nose is pinched with crusts on the lips and the forehead is clammy (page 27) |
| Marfanoid (page 50) |
| Mitral (page 57) |
| Myopathic (page 391) |
| Myotonic (page 392) |
| Myxoedematous (prolonged hypothyroidism) (page 305) |
| Pagetic (page 320) |
| Parkinsonian (page 396) |
| Ricketic (page 314) |
| Thyrotoxic (page 302) |
| Turner’s syndrome (page 314) |
| Uraemic (page 207) |
| Virile facies (page 315) |
Figure 3.2 Some important diagnostic facies: (a) myopathic; (b) myotonic
From Mir MA, Atlas of Clinical Diagnosis, 2nd edn. Edinburgh: Saunders, 2003, with permission.
Cyanosis
This refers to a blue discoloration of the skin and mucous membranes; it is due to the presence of deoxygenated haemoglobin in superficial blood vessels. The haemoglobin molecule changes colour from blue to red when oxygen is added to it in the lungs. If more than about 50 g/L of deoxygenated haemoglobin is present in the capillary blood, the skin will have a bluish tinge.7 Cyanosis does not occur in anaemic hypoxia because the total haemoglobin content is low. Cyanosis is more easily detected in fluorescent light than in daylight.
Central cyanosis means that there is an abnormal amount of deoxygenated haemoglobin in the arteries and that a blue discoloration is present in parts of the body with a good circulation, such as the tongue. This must be distinguished from peripheral cyanosis, which occurs when the blood supply to a certain part of the body is reduced and the tissues extract more oxygen than normal from the circulating blood: for example, the lips in cold weather are often blue, but the tongue is spared. The presence of central cyanosis should lead one to a careful examination of the cardiovascular (Chapter 4) and respiratory (Chapter 5) systems (see also Table 3.2).
| Central cyanosis |
Pallor
A deficiency of haemoglobin (anaemia) can produce pallor of the skin and should be noticeable, especially in the mucous membranes of the sclerae if the anaemia is severe (less than 70 g/L of haemoglobin). Pull the lower eyelid down and compare the colour of the anterior part of the palpebral conjunctiva (attached to the inner surface of the eyelid) with the posterior part where it reflects off the sclera. There is usually a marked difference between the red anterior and creamy posterior parts (see Figure 13.3a, page 425). This difference is absent when significant anaemia is present. Although this is at best a crude way of screening for anaemia, it can be specific (though not sensitive) when anaemia is suspected for other reasons as well (Good signs guide 3.1). It should be emphasised that pallor is a sign, while anaemia is a diagnosis based on laboratory results.
| Sign | Positive LR* | Negative LR† |
| Pallor at multiple sites | 4.5 | 0.7 |
| Facial pallor | 3.8 | 0.6 |
| Palm crease pallor | 7.9 | NS |
| Conjunctival pallor | 16.7 | − |
NS = not significant.
* Positive likelihood ratio: when the finding is present, describes the probability change. The higher the LR is above 1, the more likely there is disease.
† Negative likelihood ratio: when the finding is absent, describes the probability change. The closer the LR is to 0, the more likely there is not disease.
From McGee S, Evidence-based physical diagnosis, 2nd edn. St Louis: Saunders, 2007.
Facial pallor may also be found in shock, which is usually defined as a reduction of cardiac output such that the oxygen demands of the tissues are not being met (Table 3.3). These patients usually appear clammy and cold and are significantly hypotensive (have low blood pressure) (page 27). Pallor may also be a normal variant due to a deep-lying venous system and opaque skin.
