I distinctly remember clapping the day I watched Hugh Laurie diagnose somebody with lupus on the show House. Before you rush into a hasty condemnation of this writer, a little bit of background: there was a running gag on the show wherein Dr House (Laurie) would make an initial diagnosis of lupus and follow it up with the quip, “It’s never lupus,” because, sure enough, the patient would start showing symptoms that would contradict the diagnosis, sending Dr House and his team back to the drawing board, quite literally. It’s important to note that despite the high stakes involved, the business of diagnostic medicine offers up thrills very similar to a Sherlock Holmes whodunit: the show, an oblique tribute to Holmes proves this.
A lot of the diagnostic passages in oncologist and author Siddharth Mukherjee’s The Laws of Medicine (TED Books/Simon & Schuster India) read like something out of a House episode. There’s the strange case of Mr Carlton, for example, a 56-year-old Boston man, “(…) a resident of Beacon Hill, the tony neighbourhood with brick town houses and tree-lined, cobble-stone streets that abuts Massachusetts General Hospital.”
Carlton was obviously affluent, did not smoke or drink and yet, suffered from a sudden, acute loss of weight. And he was testing negative for cancer. How, then, did he lose nearly 26 pounds in less than 4 months? And then, later that evening, Mukherjee saw Carlton chatting with a man admitted months ago for a skin infection related to persistent heroin usage. As Mukherjee says, “(…) the image kept haunting me: the Beacon Hill scion chatting with the Mission Hill addict. There was a dissonant familiarity in their body language that I could not shake off; a violation of geography, of accent, of ancestry, of dress code, of class.”
Mukherjee’s prose never lets you out of the loop, even when he is describing inferences based on some very detailed scientific knowledge. Moreover, his allusions cover a broad range of pop culture, something that reels you in as a reader.
Mukherjee put two and two together: Carlton was a habitual heroin user himself. The next morning, Carlton was tested for AIDS and the test came back positive. This anecdote has been used to underline the first of Mukherjee’s three “laws”: a strong intuition is much more powerful than a weak test. But these are not laws in the conventional sense of the word, as the author explains. These are principles common to every discipline that plays the probabilities game, namely Bayes Theorem: the probability of two mutually exclusive events happening at the same time is the product of the individual probabilities. As the author point out, this can have serious repercussions when a diagnostic test applied to a target group already susceptible to a particular ailment (like the Mission Hill addicts).
Observations like these make The Laws of Medicine such a fascinating read. Mukherjee’s prose never lets you out of the loop, even when he is describing inferences based on some very detailed scientific knowledge. Moreover, his allusions cover a broad range of pop culture, something that reels you in as a reader. His previous book, The Emperor of All Maladies, was a magisterial examination of cancer that won the Pulitzer Prize for Non-Fiction. At 70 pages lengthwise, this sharp little book is more like a long essay, but its impact is considerable.
There is yet another reason why interventions like Mukherjee’s are so valuable. Today, there are all manner of websites and apps that give away highly specialised medical data: some of these portals offer diagnostic advice as well. But you would be a fool to place your trust entirely in automated diagnoses: to that end, it is lucky that the shamanic quality of doctors isn’t quite extinct yet. As Mukherjee says, the real skill of a doctor is to make decisions in the absence of a complete set of data. Dr House would have approved.