Conventional Clinical Practice
1.2a The conventional medicine approach
Conventional medical training
Conventional training in medicine (and also the paramedical professions such as nursing, physiotherapy and occupational therapy) is based largely on teaching scientific method and how this applies to health.
The early years of medical school training are focused on the sciences of anatomy, biochemistry, physiology, pathology, pharmacology and psychology. From the outset of the training, medical knowledge in these areas tends to be taught as accepted fact, and there is relatively little emphasis on the history of medicine or on the philosophy that underlies current medical thought. The medical student will, through study, become very familiar with the biomedical model that recognizes the physical basis of the body and its complex physiological processes as measurable domains. Health will be primarily described in the early stages of training in terms of absence of illness or injury,7 although there will also be recognition that health is better described in terms of mental and social functioning as well as parameters of physical health. This is in keeping with the, at the time groundbreaking, broader definition of health first adopted by the World Health Organization (WHO) in 1946 as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”8 However, there will be little introduction, if any, in the training to contrasting medical philosophies such as those that underpin Chinese medicine, Ayurvedic medicine or homeopathy, or to the idea supported within these healing traditions that health might relate to the energetic balance of the human being within the wider energetic system of the universe. The concept, sometimes described as vitalism, which links these alternative medical disciplines (defined as “the theory that the origin and phenomena of life are dependent on a force or principle distinct from purely chemical or physical forces”9), is not embraced within modern biomedical training courses.
As the training progresses, medical students are given increasing contact with patients in a hospital setting. It is in this clinical setting that the skills of case history taking, clinical examination, diagnosis and treatment are taught. Much of the learning is by example, as students accompany doctors in their practice in the clinic or on the ward.
In the clinical setting the patient is the stimulus for the teaching, which is often in the form of encouraging rapid recall of relevant facts about the case in question. For example, the teaching doctor might ask of a student: “This patient has renal failure. What are the causes of renal failure?” The student is expected to reply with a systematic and complete list of causes of the condition in question. In this way, the diagnostic process becomes ingrained as a reflex in which, with the presentation of characteristic symptoms and signs in a patient, appropriate diagnoses can be made and treatment selected.
Medical training emphasizes the development of skills in eliciting the symptoms and signs of disease through sensitive questioning and physical examination of the patient, and also in-depth knowledge of all possible biomedical diagnoses and treatment options. At the end of their training, clinicians should have developed an ability to put their patients at ease, finely tuned examination skills, a facility in recalling and structuring facts in a rigorous way, and they will also become adept at accessing the ever-changing current medical literature.
Development of a doctor–patient rapport to enable the eliciting of symptoms from a patient is considered essential, and so the foundations of skills in communication are laid down in the early years of medical training. These skills are further honed in later aspects of medical training, particularly in the more person-centered specialties of general practice and psychiatry.
How disease is defined in conventional medicine
As described in Chapter 1.1, medical textbooks describe the defining characteristics of a disease within a series of categories. For example, the characteristics of chickenpox could be presented as shown in Box 1.2a-I. This systematic ordering of information encourages comparison between different diseases, and is a prerequisite for the formation of a differential diagnosis of all the diseases that might be affecting a patient with certain features.
In forming a definition such as this one for chickenpox, the focus is on the characteristic pattern of the disease as it might affect any person, and not on the individual characteristics of the patient.
This model of disease might be described as “reductionist,” a term that describes the analysis of a complex system in terms of how it is made up of its more simple constituent parts. The reductionist aspects of modern medicine are explored in more detail in Chapter 1.3.
Box 1.2a-I Defining characteristics of chickenpox
Name:Primary herpes zoster (chickenpox).
Epidemiology:Universal; 95 percent of people in metropolitan communities have had the infection by adulthood.
Etiology/cause:Herpes zoster virus infection. Droplet spread of vesicle fluid.
Symptoms and signs:13- to 17-day incubation period followed by sudden onset of fever, mild constitutional malaise and, after two days, a widespread vesicular rash with lesions appearing in crops, mainly on the trunk. Lesions leave a scab after rupturing in 3–4 days. Symptoms can be more severe in adults. Complications include bacterial infection of lesions, pneumonia and encephalitis. Can manifest later in life as secondary herpes zoster (shingles).
Investigations:Can be diagnosed by clinical features alone. Rising antibodies can be assayed after 3–4 days (blood test).
Treatment:Usually for symptoms only. In severe cases or vulnerable individuals, treat as soon as possible with oral or intravenous antiviral medication such as acyclovir. Treat infected lesions with oral flucloxacillin or alternative antibacterial medication.
Prognosis:Usually mild and self-limiting. Case fatality: 2/100,000 in children, 30/100,000 in adults.
Prevention:Live attenuated vaccine available for susceptible children in UK and part of usual program in US. Varicella zoster immune globulin can be given within four days of exposure to reduce risk of contracting severe disease in those who are immunocompromised (e.g. patients with leukemia or acquired immune deficiency syndrome, AIDS).
Differential diagnosis:No other illnesses present in this way, but other infectious diseases such as measles, rubella and scarlet fever may be considered in the differential diagnosis.
The stages of disease diagnosis
Disease is diagnosed in three stages that enable the doctor to match the individual patient with the descriptions of diseases that become so familiar through the course of medical training. These stages are: questioning for the presence of symptoms, examining the body for signs, and checking the results of tests. Although a great deal of emphasis can be placed on the results of tests, it is recognized that over 70 percent of diagnoses can be made with skillful questioning of the patient alone.10 Adding in the results of physical examination can bring this diagnosis rate up to about 90 percent.
Thus, together, symptoms and signs will offer the necessary information for making a firm diagnosis in the large majority of situations. Doctors have been trained to respond to characteristic symptoms and signs (e.g. central chest pain or a painless red rash) by generating a mental list of possible causes. This is the beginning of forming a differential diagnosis. As an aide-memoire, a systematic approach is applied, and diseases that might originate in each of the circulatory, respiratory, digestive, urinary, nervous, endocrine, musculoskeletal and reproductive systems may be considered to start building up this list. Possible infective, inflammatory, degenerative, malignant, social and psychological causes are also brought to mind. This systematic technique for differential diagnosis relies very much on the prior memorization of many medical facts.
With a list of possible diagnoses to hand, the doctor is then ready to ask more questions to narrow down the diagnosis, to examine the patient further, and also to consider whether any investigations might provide further diagnostic information.
Medical tests are thus most often employed to confirm the most likely underlying condition, and to exclude less likely diagnoses. Tests are also used for monitoring treatment. An example would be a blood test for the thyroid-stimulating hormone (TSH) to confirm hypothyroidism in somebody with tiredness, weight gain and a slow pulse. An initial measurement that is well above the normal range would help confirm the diagnosis. TSH levels would be retested after treatment has been instated, and would be expected to drop, thus indicating a good response.
For the practitioner of Chinese medicine, the same three steps of questioning to elicit symptoms, physical examination to elicit signs and, to a lesser extent, performing tests (investigations) are, of course, also used in the diagnostic process.
Questioning for symptoms
The approach to the questioning of the patient in conventional medicine is very similar to the approach taught in the practice of Chinese medicine. Doctors will rely on an internal checklist to guide them through the questioning of patients about their symptoms. The nature of the symptoms can be clarified by the use of nine questions. These relate to the site of the symptom, to where it might radiate, its character, its severity, the time of its onset, its frequency, its duration and any accompanying symptoms. Finally, the patient is asked what factors make the symptom better or worse. In this way the patient is encouraged to give far more information about their experience than they might have naturally expressed. As already explained, the level of detail that is generated by questioning in this way is very often sufficient to suggest the correct diagnosis.
Examination for signs
A medical doctor will take a systematic approach to the physical examination of the body. This is intended to reveal any bodily changes that might indicate the presence of physical disease. The systematic approach involves examining the different systems of the body in turn, and when done thoroughly can take up to many minutes. When there is pressure of time doctors will narrow down this approach to examination of just those areas of the body that appear to be relevant after questioning for symptoms.
Box 1.2a-II illustrates these first two stages of the diagnostic process.
However, it is a rather unsatisfactory aspect of clinical medicine that not all symptoms and signs fit easily into diagnostic categories. Many patients suffer from functional symptoms that may be unique to their individual situation, and there may be no measurable pathological disease process to explain them. For example, syndromes such as chronic fatigue syndrome, panic disorder and irritable bowel syndrome may present with a constellation of physical symptoms and signs, none of which can be clearly attributed to underlying physical disease.
Medical investigations or tests are performed to narrow down a diagnosis and also to monitor the progress of treatment.
The diagnostic aspect of tests can be illustrated by continuing with the case scenario given in Box 1.2a-II, as described in Box 1.2a-III. This illustrates the process of diagnosis and choice of treatment. When this process leads to a clear diagnosis, it becomes a very satisfying aspect of the practice of medicine. The diagnosis is made by a logical process of elimination, and the treatment for a clear diagnosis is usually obvious from the current medical literature.
In practice, refining the diagnosis on the basis of tests may not always be that straightforward. There can be uncertainty around the reliability of characteristic diagnostic signs as indicators of disease. Not all symptoms, signs and positive test results indicate the disease to which they seem to point, in which case they are known as false-positive findings.
Similarly, not all normal measurements are indicative of health; in some people with disease, tests results are within the normal range, and this would be described as a false-negative result. Some of the uncertainty in diagnosis stems from limitations in the measurability of bodily functions.
Ian, a 63-year-old man, has noticed that he has started to get up at night to urinate, and goes to see his doctor.
This symptom is known as nocturia. The checklist for the possible causes of nocturia includes:
•endocrine causes such as diabetes
•urinary causes such as chronic renal failure
•degenerative change leading to benign enlargement of the prostate gland
•malignant causes such as prostate cancer
•social causes such as drinking too much alcohol or caffeine late at night
•psychological causes such as anxiety with insomnia.
Ian’s doctor uses questioning and examination to find out more about the nocturia. In response to her questions, Ian tells her that he has had the problem for some months, when it started with having to get up just once in the night. Now he gets up three or more times, but more often than not just passes a few dribbles of water, and he usually has to wait at the toilet for some time. Otherwise he is well, so there are no accompanying symptoms. He finds that cutting down on all fluids in the evening improves his chances of a less disturbed night.
The doctor performs a physical examination, which involves examination of the prostate gland. This can be felt just inside the anus. Ian’s prostate gland feels smooth but significantly enlarged, and has a rubbery texture. There are no other physical abnormalities.
The task of Ian’s doctor is to start to match the symptoms and signs of Ian’s condition with the conditions that she knows can cause nocturia. The physical findings, together with a characteristic history, alert her to the possibility that constriction of the urethra by an enlarged prostate gland might be the cause of the problem. She reaches this conclusion because she knows that a common cause of nocturia in men of Ian’s age group is benign enlargement of the prostate gland, also known as benign prostatic hyperplasia (BPH). BPH results in gradual obstruction of the urethra, which is the tube that leads from the bladder to the penis. This means that efficient emptying of the bladder is no longer possible, and this leads to a frequent urge to pass small amounts of urine.
An important diagnosis to exclude is prostate cancer, which can also cause symptoms of lower urinary tract obstruction. Both prostate cancer and BPH tend to occur in older men, although BPH is more likely to first present at an earlier age than cancer. Another similarity is that a sign of prostate cancer is an enlarged prostate gland, but the prostate is often irregular and hard. In contrast, in BPH, it is smooth and rubbery. This finding cannot be relied on as prostate cancer can be located deep in the gland and may not produce a perceptible change to the feel of the exterior of the gland on physical examination.
A medical textbook might systematically define BPH as follows:
Name:Benign prostatic hyperplasia (BPH).
Etiology/cause:Degenerative (aging) disease of unknown cause (a change in balance in the proportion of the hormones testosterone and estro-gen is thought to be contributory).
Incidence:In most men over 60 years of age (and 90 percent of those over 90).
Symptoms:Nocturia, difficulty in urination, dribbling, poor stream.
Signs:Smooth, enlarged prostate gland felt on rectal examination.
Investigations:Test urine for infection (culture), blood test to exclude diabetes and kidney disease and assessment of prostate-specific antigen (PSA) to exclude cancer. Detailed imaging of the kidneys and bladder (X-ray and ultrasound) to exclude the kidney problems that can result from prolonged BPH.
Treatment:Drug treatment if mild; surgical resection of the prostate gland if severe.
It is clear that Ian’s doctor needs first to eliminate the diagnosis of prostate cancer before treating Ian for BPH.
It is clear that Ian’s doctor needs first to eliminate the diagnosis of prostate cancer before treating Ian for BPH, and so she arranges for some tests to be performed, including blood tests for PSA and markers of renal function, and an ultrasound scan of Ian’s bladder and kidneys.
On completion of the investigations, Ian’s bladder and kidneys do not appear to be damaged, and the PSA test is negative.
The doctor can then explain to Ian that it appears that it is most likely he has a mild form of BPH, which is part of the normal aging process for many men. She might then explain the current treatments for BPH, according to current professional guidelines, which include drug treatments or surgery. She might discuss the pros and cons of these options. This is intended to leave Ian with sufficient information to make a decision about which treatment options he might follow.
Measurability in medicine