I'm a consultant chest physician at the Liverpool Heart and Chest Hospital, and have a special interest in TB. Four or five years ago I crossed a colleague in the car park who mentioned a patient of his to me. He said, "Peter, I've got this 50-year-old lady, she does a lot of travelling, and she's got a swelling in her neck. I've been draining off lots of pus, but it's always come back negative – no growth of any bacteria. I wonder if she's got TB?" It sounded very likely, so I asked him to send her over to me. Then he said: "Punchline – she's a barrister!"
It's very common for doctors to be worried treating barristers. Solicitors fine, priests fine, everyone else fine, barristers you think, "Oh gosh". If you get it wrong, things can move very quickly. The problem with this case was that there were no symptoms to suggest she had TB at all; all she had was this lump in her neck, which was soft and fluctuant, just under the angle of the jaw on the left, about the size of a large plum. It had been there off and on for several months.
The way to prove TB is to get a specimen from the diseased part, and grow the bug yourself. Time and time again we did this and it never grew. Eventually I did a simple test we do, the old-fashioned skin test, and it came back strongly positive. With the story, the history and the evidence of the skin test, it was just enough of an indication to persuade me to start her on treatment for TB.
Now, the treatment for TB is actually quite extensive and there are many side-effects, with the chances of getting them reasonably high. The total length of treatment is six months. If you get it wrong, you do the patient a great disservice.
I said to her: "Look, I have no proof this is TB, I just believe it is. You understand the difference between the criminal prosecution, where you must prove beyond reasonable doubt, and the civil prosecution, which is on a balance of probability." And she told me she understood that very well. So we went down the course of treatment along those lines. But I was always wary because, as with many cases of TB that occur outside of the lung, you never actually get bacteriological proof.
So when I first saw her after I'd started the treatment and she came out with this list of every side-effect under the sun, I thought, "gosh, the TB treatment is making her feel so much worse". Then I said, "well, what about the lump?" and she said, "oh, it's gone". This is a strange way for a patient to respond; the way she first described the side-effects and then said the lump was gone. That was a really ghastly moment, when she listed these side-effects for about five minutes. That was really the worst time, but also the point of relief when it went from terrible to fantastic.
A few months later it was a case of patient cured – signed, sealed and delivered. She even gave me a couple of tickets to Glyndebourne opera house.
Professor Davies is also a trustee of TB Alert www.tbalert.org. Interview by Will Coldwell