Matt Morgan: Sin-drome—the phenomenon of missing-diagnosis

“We’ve had a new admission into bed 3”
“Great, I’ll be right there, what’s wrong with them?”
“He’s got multiorgan failure but was intubated mainly for respiratory failure”
“Ah ok, what’s wrong with him?”
“ARDS”
“Caused by what?”
“Sepsis I think”
“From what?”
“Pneumonia”
“What type?”
“Um . . .”
“Don’t worry, let’s see him together . . .”

In intensive care, we are as guilty as the next medical professional for speaking in terms of syndromes—ARDS (adult respiratory distress syndrome), IAH (intra abdominal hypertension), AKI (acute kidney injury), MOF (multi-organ failure) to name but a few. Their use makes communication easier, it shortens the descriptions needed for referral, risk prediction and effective handover. However, this leads to one disadvantageous consequence—not mis-diagnosis but the phenomenon of missing-diagnosisThis is precipitated by the acceptance of a syndrome as the end of a diagnostic process. I would like these conclusions renamed as a sin-drome.

A timely and correct diagnosis remains the cornerstone of modern medicine. Whilst one can talk about personalised medicine and high-fidelity care, these rely upon the bedrock of diagnosis. It is true that patients can sometimes get better even without a correct diagnosis. We often have limited evidence-based therapies to offer, especially in critical illness. Therefore, we find ourselves using the triad of surgery, antibiotics, and time as the only means to recourse when the aetiology of illness is uncertain.

However, there are many patients that cannot get better without a diagnosis. The patient shocked due to autoimmune-Addison’s disease, the patient with sepsis due to hidden aortic valve Staphylococcus aureus endocarditis, the young patient with multiorgan failure due to Behçet’s disease. These need specific treatments, delivered in certain ways, directed at specific entities, delineated by a correct, timely diagnosis.

Arriving at the correct diagnosis however is difficult, time consuming, and fraught with error. Even in the high-tech, no-expenses-spared environment of critical care, as many as 50% of diagnoses are wrong. To arrive at the correct diagnosis, we need to overcome cognitive biases including anchoring bias (the patient with “sepsis” who actually has acute gallstone pancreatitis) and confirmation bias (“ah yes, it does look like pneumonia on the chest x-ray” in the patient with systemic lupus erythematosus related diffuse alveolar hemorrhage). We cannot rest on our assumptions, we must challenge ourselves to alternatives and force our mind to get to work. We must be doctors not zombies.

The first step along this journey is to read the excellent “Twelve tips for teaching avoidance of diagnostic errors.” It should be compulsory reading for all medical students and doctors alike. Medical schools, postgraduate bodies, and teachers alike should be embracing these challenges and educating future doctors on the issues surrounding diagnostic error. My own process involves asking three questions. What is the most likely diagnosis? What is more unlikely? What, if I miss it, will lead to death, disability or being sued? Avoiding a mental full-stop and continuing to explore further, even question, a diagnosis after it has been made is key.

Avoidance of the sin-drome is not only important for direct patient care, but is increasingly important in evidence-based medicine. My own field of “sepsis” research has suffered countless so-called “negative” trials partially due to grouping together patients with diagnoses as different as Streptococcus pneumoniae with Staphylococcus aureus soft tissue infection. These entities are not the same despite falling under the umbrella of causing “septic shock.” If we are to have personalised medicine, then we will need personalised trials, focussing on a diagnosis and not simply a sin-drome. Let’s fight against the sin-drome and missing-diagnosis towards something (slightly) closer to truth.

Matt Morgan is an intensive care consultant, scientist, computer programmer, teacher and geek interested in machine learning, medical education and public engagement. @Matrix_Mania

Competing interests: I have spoken at a number of education events for which standard travel expenses have been reimbursed. I received a research grant from Heath Research Wales and the Medical Research Council in 2016. I am paid as the lead clinical editor for BMJ’s onExamination.

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