‘Delicate diagnosis’: avoiding harms in difficult, disputed, and desired diagnoses

[摘要] Medical diagnoses can be subject to ambiguity, flux, subjectivity, and inherent uncertainty. This is particularly true in primary care, where many reported symptoms do not conform to a clear diagnosis. Thresholds around normality are often unclear.Symptoms are commonly experienced and described as an ’iceberg’. Over a third of otherwise well people without a chronic condition have felt tired or run down, or had a headache in the previous 2 weeks, and over a quarter have had back or joint pain. Distinguishing conditions that would benefit from diagnosis and earlier intervention from those that are temporary, self-limiting, and prone to harmful medicalisation, remains challenging.While overdiagnosis is a diagnosis of a condition that, if unrecognised, would not cause symptoms or harm, contested diagnoses are symptoms given a diagnosis, but where the diagnosis, as an explanation for them, is controversial. Opponents consider contested diagnoses ‘wrong’ not because of an error in history taking, clinical examination, or interpretation of a test result (which would risk misdiagnosis), but because the diagnosis itself, for example, chronic Lyme disease or multiple chemical sensitivity, is invalid.Contested diagnosis is bordered by ‘pseudoscience’, for example, adrenal fatigue, leaky gut syndrome, and chronic candidiasis, which attempt to explain symptoms with ‘science’ that is demonstrably incorrect.Many contested diagnoses relate to symptoms that are not clear-cut, meaning that some people are given a diagnosis that does not confer benefit. Others are primarily unexplained ‘yet’. For example, Gulf War syndrome was treated as a contested illness but is now recognised as caused by exposure to sarin gas. Other recognised conditions are prone to a variety of influences such that diagnosis risks causing harm, through a variable mixture of misdiagnosis, overdiagnosis, pseudoscience, or overtreatment.A framework for considering some conditions as ‘delicate diagnoses’ may help to recognise and reduce the harms of medicine in these circumstances.DELICATE DIAGNOSIS A variety of models have been used to describe and explain how diagnoses are reached by doctors. Heuristics — rules-of-thumb — discounts less important information to pragmatically reach likely probabilities, while responding to environmental circumstances. Bayes’ rule means that small pieces of information can have a profound impact, with prior probabilities of disease rapidly shaping possibilities.GPs work mainly from ‘mindlines’, ‘collectively reinforced, internalised, tacit guidelines … informed by brief reading, but mainly by their interactions with each other and with opinion leaders, patients, and pharmaceutical representatives’. Similar heuristic styles may be true for patients. This gives rise to the potential for bias, and the associated harms of poor-value care, overdiagnosis, and overtreatment.

[学科分类] 卫生学