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How to undo a dodgy diagnosis

Jobbing Doctor heeds the wise words of a brilliant polymathic physician

When I was a medical student, many years ago, we still had a reasonably sensible number of books to read. Medical science was less complex than today, and so we had the opportunity to read books about medicine in its broadest aspects.

One of these books was by a physician called Richard Asher, and it was called 'Talking Sense'. I read the book through, and from time to time I read it again. It still has strong messages.

Asher was a brilliant, polymathic physician who described, for the first time, Myxoedematous madness and Munchausen's syndrome. One of the phrases I remember well was the very telling advice that ‘one of the worst things a doctor can do is to repeat the mistakes of other doctors'. This advice I have tried to follow throughout my career.

We were musing on this the other day. After morning surgery we all congregate in the upstairs room, have a coffee, sign prescriptions, deal with enquiries, sort out the visiting lists and discuss matters. Generally it is about gossip, or cricket, or shoes (I have three pairs; one of my new partners has over 300 pairs). Sometimes one of us likes to discuss a clinical conundrum, or whinge.

And so it was last week, when the topic was undiagnosing, or proving wrong a previously made diagnosis.

General practitioners are not supposed to question the diagnoses of specialists. We are clinicians who know a little about most things, whereas a specialist is someone who knows a lot about very little. Except, sometimes diagnoses are made on the basis of a very narrow interpretation. So, for example, it is a heart attack if the Troponin is greater than 1. Always. Anyone with weakness down one side of the body has had a transient ischaemic attack. Always.

I had a patient who had a diagnosis of a stroke. She was on aspirin, clopidogrel, a statin and a beta-blocker. She had had recurrent episodes of weakness down one side of the body. She had had the full investigation - bloods, carotid scans, CT angiograms, the lot. She was confidently diagnosed as having recurrent cerebral ischaemic attacks. She wanted to move house but was denied insurance because of her diagnosis.

Then we became her doctors.

It is often helpful when you are a new doctor to a patient, as you don't come to the case with any prior knowledge. A blank sheet. Tabula rasa. I was unhappy about her case, as she was a non-smoking, non-hypertensive, non-diabetic female with no family history. And she was only 31 years old.

The first thing to do if you are unhappy about a diagnosis is to start at the beginning. This is what I did. It was clear to me that the diagnosis was palpably wrong. And I am only a Jobbing GP. I set to work on undiagnosing her. That took months. She is off all the unnecessary medicine, and I am now treating her for her hemiplegic migraine.

She is relieved that the sword of Damocles has been removed from above her head. She did reapply for insurance, and was turned down a second time. Maybe the medical officer preferred to believe a dodgy diagnosis from a ‘specialist' as opposed to a correct diagnosis from a generalist.

I thought that this might be a unique case, and my patient was unfortunate to be sloppily diagnosed. However, when I was talking to my colleagues, at least two of them had similar experiences of misdiagnosis.

So, remember Asher's advice: the worst thing a doctor can do is to repeat the mistakes of other doctors.

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

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