Chapter 24: Cautionary methods: towards a safe diagnostic strategy

The stories told in this book demand that general practitioners have an incisive detective-like approach to our discipline, which is arguably the most difficult, complex and challenging of the healing arts. Our field of endeavour is at the very front line of medicine, and as practitioners of first contact we shoulder the responsibility of the early diagnosis of very serious, perhaps life-threatening, illness in addition to the recognition of anxiety traits in our patients.

Over and over again the old medicine adage ‘More things are missed by not looking than by not knowing’ has been stressed. However, our area is characterised by a wide kaleidoscope of presenting problems, often foreign to the classic textbook presentation and sometimes embellished by a ‘shopping list’ of seemingly unconnected problems—the so-called undifferentiated illness syndrome. It is important, especially in a busy practice, to adopt a fail-safe strategy to analyse such presenting problems. Such an approach is even more important in a world of increasing medical litigation and specialisation.

To help bring order to the jungle of general practice problems the author has developed a simple model to facilitate diagnosis and reduce the margin of error.

The use of the diagnostic model requires a disciplined approach to the problem with the medical practitioner having to quickly answer five self-posed questions. The questions, for a particular patient, are as shown below.

This approach, based on considerable experience, requires the learning of a predetermined plan, which naturally would vary in different parts of the world but would have a certain universal application in the so-called developed world.

Each of the above five questions will be expanded.

1. What is the probability diagnosis?

The probability diagnosis is based on the doctor’s perspective and experience regarding prevalence, incidence and the natural history of disease. The general practitioner acquires first-hand epidemiological knowledge about the patterns of illness (apparent in individuals and in the community) that enables him or her to view illness from a perspective that is not available to doctors in other disciplines. Thus, during the medical interview, the doctor is not only gathering information, allocating priorities and making hypotheses, but is also developing a probability diagnosis based on acquired epidemiological knowledge.

2. What serious disorder(s) must not be missed?

While epidemiological knowledge is a great asset to the general practitioner, it can be a disadvantage in that what is common is so familiar that the all-important rare cause of a presenting symptom may be overlooked. On the other hand, the doctor in the specialist clinic, where a different spectrum of disease is encountered, is more likely to focus on the rare at the expense of the common cause. However, it is vital, especially working in the modern framework of a litigation-conscious society, not to miss serious, life-threatening disorders.

To achieve early recognition of serious illness the general practitioner needs to develop a ‘high index of suspicion’. This is generally regarded as largely intuitive, but this is probably not so, and it would be more accurate to say that it comes with experience.

The serious disorders that should always be considered ‘until proved otherwise’ include malignant disease, AIDS, coronary disease and life-threatening infections such as meningitis, septicaemia and bacterial endocarditis (see the list titled ‘Serious, not-to-be-missed conditions’).

Acute coronary syndromes, especially myocardial infarction, are extremely important to consider because they are potentially lethal and at times can be overlooked by the busy practitioner. It does not always manifest as the classic presentation of crushing central pain; it can present as pain of varying severity and quality in a wide variety of sites. These sites include the jaw, neck, arm, epigastrium and interscapular region (Figure 24.1).

Coronary artery disease may manifest as life-threatening arrhythmias, which may present as palpitations and/or dizziness. A high index of suspicion is necessary to diagnose arrhythmias.

A useful mnemonic for thinking danger is VIC:

• vascular

• infection (severe)

• cancer.

Red flags

Red flags (alarm bells) are symptoms or signs that alert us to the likelihood of significant harm. Examples include weight loss, persistent vomiting, altered cognition, fever > 38 °C, dizziness/syncope (especially at the toilet) and pallor.

Think fast with management of infarction

Remember the ideal intervention time rules:

• acute coronary states—60 to 90 minutes

• stroke—cerebral infact—3 to 4 hours

• femoral artery—4 hours

• limb salvage––4 hours; more than 6 hours = limb amputation

• torsion of testes––4 to 6 hours.

3. What conditions are often missed?

This question refers to the common ‘pitfalls’ so often encountered in general practice. This area is definitely related to the experience factor and includes rather simple non-life-threatening problems that can be so easily overlooked unless doctors are prepared to include them in their diagnostic framework. Examples include smoking or dental caries as a cause of abdominal pain; occupational or environmental hazards as a cause of headache; and faecal impaction as a cause of diarrhoea. We have all experienced the ‘red face syndrome’ from a urinary tract infection, whether it is the cause of fever in a child, lumbar pain in a pregnant woman or malaise in older person. Other classic pitfalls include allergies, Candida albicans infection, domestic abuse including child abuse, drugs, foreign bodies, menopause syndrome, early pregnancy, Paget disease, coeliac disease, haemochromatosis, endometriosis, sarcoidosis, faecal impaction, migraine (atypical variants) and seizure disorders.

4. Could this patient have one of the ‘masquerades’?

The author sometimes refers to these important problems as the ‘sins of omission’ in general practice, because the conditions appear to be so often overlooked as the cause of the symptom complex in the patient presenting with undifferentiated illness.

It is important to utilise a type of fail-safe mechanism to avoid missing the diagnosis of these disorders. Some practitioners refer to consultations that make their ‘head spin’ in confusion and bewilderment with patients presenting with a ‘shopping list’ of problems. It is in these patients that a check list is useful. Consider the apparent neurotic patient who presents with headache, lethargy, tiredness, constipation, anorexia, indigestion, shortness of breath on exertion, pruritus, flatulence, sore tongue and backache. In such a patient we must consider a diagnosis that links all these symptoms, especially if the physical examination is inconclusive and this includes iron-deficiency anaemia, depression, diabetes mellitus, hypothyroidism or drug abuse.

A century past it was important to consider diseases such as syphilis and tuberculosis as the great common masquerades, but these infections have been replaced by iatrogenesis, malignant disease, alcoholism, endocrine disorders and the various manifestations of atherosclerosis, particularly coronary insufficiency and cerebrovascular insufficiency.

If the patient has pain anywhere it is possible that it could originate from the spine, and so the possibility of spinal pain (radicular or referred) should be considered as the cause for various pain syndromes such as headache, arm pain, leg pain, chest pain, pelvic pain and even abdominal pain. The author’s experience is that spondylogenic pain is one of the most underdiagnosed problems in general practice.

A check list has been divided into two groups of seven disorders (see the lists titled ‘The seven primary masquerades’ and ‘The seven other masquerades’). The first list of the primary masquerades represents the more common disorders encountered in general practice; the second list includes less common masquerades although the latter is more relevant to consultant practice. Some conditions in the second list–such as infectious mononucleosis–can be very common masquerades in general practice. As a practical diagnostic ploy, the author has both lists strategically placed on the surgery wall immediately behind the patient. The lists are rapidly perused for inspiration should the diagnosis for a particular patient prove elusive.

5. Is the patient trying to tell me something else?

The doctor has to consider, especially in the case of undifferentiated illness, whether the patient has a ‘hidden agenda’ for the presentation. Of course, the patient may be depressed (overt or masked) or may have a true anxiety state. However, a presenting symptom such as tiredness may represent a ‘ticket of entry’ to the consulting room. It may represent a plea for help in a stressed or anxious patient. We should be sensitive to patients’ needs and feelings and as listening, caring, empathetic practitioners provide the right opportunity for the patient to communicate freely.

Deep sexual anxieties and problems, poor self-esteem, and fear of malignancy or some other medical catastrophe are just some of the reasons patients present to doctors. The author has another check list titled ‘Underlying fears or image problems causing stress and anxiety’ to help identify the psychosocial reasons for the patient’s malaise.

In the author’s experience of counselling patients and families, the problems caused by interpersonal conflict are quite amazing and make it worthwhile specifically exploring the quality of close relationships, such as the husband–wife, mother–daughter and father–son relationships.

Identification and transference of illness, symptoms and death, in particular, are important areas of anxiety to consider. Patients often identify their problems with relatives, friends or public personalities who have malignant disease.

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