Simon’s strange pains had left us baffled. Time for the surgical sieve – a tool for facing the unknown

We work through the different categories of pathology - infection, malignancy, metabolic ect, - that underlie all disease.

By Phil Whitaker

Sandy, my registrar, wanted to discuss a patient. “I’ve got absolutely no idea what’s going on,” she said, her voice both demoralised and concerned.

Simon, a 49-year-old charity administrator, had become unwell about ten days previously, three days after attending surgery for a flu jab. First, he’d noticed lancing pains in his right groin that shot down the front of his thigh. These had spread to involve the left side the following day, and he’d also developed lower back pain together with pins and needles.

As Sandy was talking, my mind began to turn over the possibilities. It sounded like a slipped disc – potentially serious, given that it was causing bilateral symptoms, which can necessitate urgent surgery to prevent permanent nerve damage, but hardly something that would have fazed Sandy. “Then he started getting the same kind of thing over his shoulders and upper arms,” she said. Suddenly, I understood her difficulty: there was no way, anatomically speaking, that could be tied in with a disc prolapse in the lower spine.

Perplexed, she’d ordered a range of blood tests. Most had come back normal, but there’d been elevation in a chemical called CRP, which can indicate an inflammatory condition, and Simon’s ferritin – which gives an idea of the body’s iron levels – was also high. “I don’t know where to start,” Sandy said.

One of the most important skills I help my registrars develop during their training is how to handle the unknown. Much of medicine is pattern recognition, but periodically cases will crop up that you’ve never encountered before. And this was certainly true for me just then. Sandy seemed a little more cheerful when I confessed I was stumped too. I started to talk her through how I would approach the scenario.

Nothing in Simon’s past, nor his family history, provided any clues. He last consulted three years ago. When someone you rarely see pitches up with something unusual it sets the antennae twitching, because often something significant is happening. The CRP and ferritin reinforced that impression. Haemochromatosis – where excess iron gets deposited throughout the body – causes a raised ferritin; Sandy had considered it, but hadn’t appreciated that inflammation will sometimes push ferritin levels up as well. “We’ll run iron studies,” I told her.

Next, I took her through the “surgical sieve”. This is a tool for generating ideas: it works systematically through the different categories of pathology – infection, malignancy, metabolic, autoimmune, and so on – that underlie all disease. By the time we’d finished, we had the growing conviction that Simon’s symptoms would probably be best explained by something localising to the spinal cord at his neck.

When we were done, I was tapping my pen on my desk. “I wonder about that flu jab,” I said. A few weeks earlier, my attention had been piqued by reports that the Oxford Covid vaccine trial had been temporarily suspended because a subject had developed symptoms consistent with transverse myelitis – a condition where an isolated section of the spinal cord inexplicably becomes inflamed. It is incredibly rare; I’ve never seen a case. But on consulting the literature, Sandy and I found the presenting symptoms paralleled Simon’s case uncannily. Furthermore, there were reports of flu vaccinations occasionally triggering the reaction.

Severe cases can develop paralysis, so we kept a careful eye on him while we finished the rest of our investigations. His raised ferritin proved to be inflammatory, and it settled as his symptoms resolved. A fascinating case, and one that illustrated that serendipity, as well as systematic tools such as the surgical sieve, can have a role in generating diagnostic ideas in medicine.