Be prepared for the unexpected

As GPs, just when we think we have seen everything, a ‘black swan’ swims into view

For many years, people believed that all swans were white because no one had ever seen a black one. To describe something as ‘rare upon the earth as a black swan’ was to denote an impossibility. The subsequent sighting of a single black swan, invalidated this entrenched belief, but also highlighted the limitation of knowledge gained purely from observation and experience. Black swans are rare birds, but they do exist and there is always a chance that one might cross your path.

 Nassim Taleb, a professor in the sciences of uncertainty in New York, developed what he called, the ‘black swan’ theory in 2001. The theory seeks to explain the disproportionate impact of rare, unpredictable events on all aspects of our lives. A black swan event is one that is unpredictable, has extreme impact, but is often rationalised inappropriately after the event.

The terrorist attack on the World Trade Centre, World War 1, the rise of the Internet, are some examples. In fact, Taleb regards most major scientific, technological, and historical events as black swans, all of them unpredictable prior to their occurrence.

Yet, despite the evidence that most of the events that have a major effect on the world and the people in it are unpredictable, we are conditioned to continually search for certainty, to believe that by increasing our overall knowledge of how things work, we will predict the future and control our own destiny. When, in fact, black swan logic indicates that what we don’t know may be much more relevant than what we do know.

Most GPs will remember the instruction, ‘when you hear hooves, think horses, not zebras.’ Horses are the equivalent of white swans and when sailing on the murky ponds of general practice, we seldom see anything else. We look for repeated patterns of illness, remember that common things are common, advise, reassure and even the most imaginative and catastrophising of us drift towards the norm amidst the plethora of viral infections, and unexplained medical symptoms. And yet, just when we think we have seen and heard everything, and begin to get complacent, a black swan swims into view.

A man with recurrent nosebleeds, (a common presentation), is diagnosed with granulomatosis, an illness with an incidence of approximately 12 per million person years. A child with a headache turns out to have medulloblastoma – a condition I have only seen once in my 30 plus years as a GP. A woman with swollen legs has Budd-Chiari syndrome (an illness so rare that it is not possible to say exactly what the incidence is, but in certain populations may be as low as 0.6 cases per million). Rare diseases have an extreme impact on the patient, but also the doctor, casting doubt on the old logic of not anticipating a zebra and changing old patterns of behaviours either temporarily or permanently.

For months after such an event, it is difficult not to send all men with nosebleeds for an ENT assessment, all children with a headache for a brain scan, and all women with swollen legs to a specialist liver unit. The quest for certainty is heightened in the aftermath of a rare event, even though the likelihood of the event happening again is extremely low.

In general practice we try to balance probability, reduce uncertainty, and predict and control the future health of our patients. We become upended by what we don’t know and feel let down by what we thought was certain. Our brains strive to reduce the cognitive dissonance of uncertainty, at huge metabolic cost. We must not miss a serious illness, but we must not over-investigate, waste healthcare resources, or cause our patients unnecessary angst.

Meanwhile, the impact of the bulk of the work we do goes unnoticed. This is because most of this work has an unquantifiable impact: Heart attacks and strokes that never happened; unwanted pregnancies avoided; children that did not die or get seriously unwell from meningococcal meningitis; cost savings arising from patients who did not go to hospital.

Taleb coined the term ‘silent heroes’ to describe all those people that we have never heard about who have saved lives and helped prevent disasters. He suggests imagining a legislator who enacted a law on September 10 2001 that imposed locked, bulletproof doors on every cockpit in case of a terrorist attack. The likelihood is that he or she would be ridiculed for squandering resources rather than celebrated with a statue in a public square.

I’m not suggesting there should be a statue of every GP in every village or town square. But I do think it is important to remember that the world needs more prevention than treatment, that we deserve to reward ourselves for the part we play in this and that while we may specialise in white swans, we must always prepare for the unexpected.