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For most diagnoses all that is needed is an ounce of knowledge, an ounce of intelligence, and a pound of thoroughness.

Anon (1951), Lancet


The discipline of general practice is probably the most difficult, complex and challenging of all the healing arts. Our field of endeavour is at the very front line of medicine and as practitioners 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.


The teaching of our craft is also an exciting challenge and presupposes that we have a profound comprehension of our discipline.


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 or vague symptoms—the so-called undifferentiated illness syndrome.1 Common undifferentiated symptoms include tiredness or fatigue, sleeping problems, anxiety and stress, dizziness, headache, indigestion, anorexia and nausea, sexual dysfunction, weight loss, loss of interest, flatulence, abdominal discomfort and chest discomfort.2 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 concept of diagnostic triads


A most useful guide to learning or memorising diagnoses, especially of elusive and uncommon conditions, is to remember three key points to the condition. The cognitive process of learning these so-called ‘triads’ and even ‘tetrads’ provides a useful template for the diagnostic methodology required in general practice. Some simple examples are shown below.


Examples such as these are interspersed throughout the text, especially in this chapter, and are prefixed by the symbol DxT.


Diagnostic triad

Examples of diagnostic triads

DxT angina + dyspnoea + blackouts aortic stenosis

DxT menstrual dysfunction + obesity + hirsutism polycystic ovarian syndrome

DxT malaise + night sweats + pruritus Hodgkin lymphoma

DxT abdominal pain + diarrhoea + fever Crohn disease

DxT vertigo + vomiting + tinnitus Ménière syndrome

DxT dizziness + hearing loss + tinnitus acoustic neuroma

DxT fatigue + muscle weakness + cramps hypokalaemia


The basic model


The use of the diagnostic model requires a disciplined approach to the problem with the medical practitioner quickly answering five self-posed questions. The questions are shown in Table 17.1.

Table Graphic Jump Location
Table 17.1

The diagnostic model for a presenting problem

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