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The era of the duckogram

Using a clinical examination to make a diagnosis may be old-fashioned, but it is still a central part of general practice says Jobbing Doctor

When I teach my students, I always try and include a section on the art of diagnosis.

I think it is an art as well as a science, and diagnosis is like a balanced Venn diagram: history, examination and investigation all form part of the means to reach a diagnosis. A three-legged stool.

Sometimes you can easily reach the diagnosis on history alone. A myocardial infarction, when it presents classically, is impossible to miss. You can diagnose it down the telephone. Asthma is often diagnosed on the history alone. It is almost as if the patients have read the textbooks.

Some conditions will be apparent as soon as you examine somebody. The rash of shingles is so very diagnostic, and there are many other conditions that can be diagnosed on a basic examination.

Some conditions will only really reveal themselves on investigation. Many is the time that I have picked up early hypothyroidism or diabetes on investigation.

For the Jobbing Doctor, however, history and examination form a greater part of the triad than investigations. I suppose it is partly because I work in primary care, and also I used to practice medicine before the advent of many investigations (fibreoptic endsocopy, TSH and T4 measures, ultrasound, CT and MRI have all arrived since I became a doctor).

Times are changing, however, and we now have some excellent tests that really help us achieve effective diagnosis. This means, however, that younger doctors rely less on clinical examination than before, with the knowledge that they can order tests anyway. How many cases of pneumonia or pneumothorax are picked up before the chest X-ray is looked at? Precious few these days.

I was musing on this the other day, when I made a diagnosis based on clinical examination findings and history. A patient came to see me, and just looked a bit pale. The patient categorically denied any symptoms, although clearly anaemic (haemoglobin was 9 g/dL), but was otherwise fine (the appointment was for a routine BP check). So I examined the abdomen. There was a firm mass in the abdomen.

So far, so straightforward. I claim no special skills here. I arranged an ultrasound, which showed the mass arising from the body of the pancreas. Urgent referral was made, and the patient was seen at a hospital clinic, and I have just got a report back from the examining doctor who acknowledged the presence of a mass, but said that, on examination, that he could feel no mass.

It hasn’t gone, as I have seen the patient since (to explain what is going on) and re-examined the abdomen. Mass still there.

So why didn’t the doctor feel the mass? Was it that he didn’t examine the patient properly? This is certainly a possibility. Was it that the doctor wasn’t very competent? Well, in terms of clinical examination, this might be the case. I think the answer lies somewhere else.

The doctor didn’t need to examine the patient to make the diagnosis. I had made the diagnosis already. He didn’t need to assess the lump, because an ultrasound will tell him much more, and more clearly. His clinical decision making had bypassed clinical examination altogether. They have already moved onto the next phase, of ‘what to do’.

I suspect that general practice will become one of the refuges of diagnosis made on clinical examination. We are now in the era of the ‘duckogram’. If it looks like a duck, quacks like a duck and waddles like a duck…’s a duck. You don’t need a duckogram to prove it.

Trouble is that many clinicians insist on the duckogram.

The Jobbing Doctor is a general practitioner in a deprived urban area of England.

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