The Rational Diagnostician and Achieving Diagnostic Excellence

Dual process models of clinical reasoning: The central role of knowledge in diagnostic expertise

RATIONALE

Research on diagnostic reasoning has been conducted for fifty years or more. There is growing consensus that there are two distinct processes involved in human diagnostic reasoning: System 1, a rapid retrieval of possible diagnostic hypotheses, largely automatic and based to a large part on experiential knowledge, and System 2, a slower, analytical, conscious application of formal knowledge to arrive at a diagnostic conclusion. However, within this broad framework, controversy and disagreement abound. In particular, many authors have suggested that the root cause of diagnostic errors is cognitive biases originating in System 1 and propose that educating learners about the types of cognitive biases and their impact on diagnosis would have a major influence on error reduction.

AIMS AND OBJECTIVES

In the present paper, we take issue with these claims.

METHOD

We reviewed the literature to examine the extent to which this theoretical model is supported by the evidence.

RESULTS

We show that evidence derived from fundamental research in human cognition and studies in clinical medicine challenges the basic assumptions of this theory-that errors arise in System 1 processing as a consequence of cognitive biases, and are corrected by slow, deliberative analytical processing. We claim that, to the contrary, errors derive from both System 1 and System 2 reasoning, that they arise from lack of access to the appropriate knowledge, not from errors of processing, and that the two processes are not essential to the process of diagnostic reasoning.

CONCLUSIONS

The two processing modes are better understood as a consequence of the nature of the knowledge retrieved, not as independent processes.

Exploring synthesis as a vital cognitive skill in complex clinical diagnosis

Clinicians employ two main cognitive approaches for diagnoses, depending on their expertise. Novices typically use linear hypothetico-deductive methods, while experts rely more on intuitive pattern recognition. These closely correspond to System 1 and System 2 thinking described in behavioral economics. We propose that complex cases additionally require the cognitive skill of synthesis, to visualize and understand the connections between various elements. To illustrate the concept, we describe a 60-year-old individual with a 6 h history of chest pain, fever, cough, accompanying chronic heart failure, atrial fibrillation, COPD, thyrotoxicosis, and ischemic heart disease. Faced with such a scenario, a bedside approach adapted by clinicians is to generate a list of individual diagnoses or pathways of pathogenesis, and address them individually. For example, this cluster could include: smoking causing COPD, IHD leading to chest pain and heart failure, and thyrotoxicosis causing atrial fibrillation (AF). However, other interconnections across pathways could be considered: smoking contributing to IHD; COPD exacerbating heart failure; IHD and pneumonia triggering atrial fibrillation; thyrotoxicosis and AF, independently worsening heart failure; COPD causing hypoxemia and worsening ventricular function. The second cluster of explanation offers a richer network of relationships and connections across disorders and pathways of pathogenesis. This cognitive process of creatively identifying these relationships is synthesis, described in Bloom's taxonomy of the cognitive domain. It is a crucial skill required for visualizing a comprehensive and holistic view of a patient. The concept of synthesis as a cognitive skill in clinical reasoning warrants further exploration.

Medicine, emotience, and reason

Medicine is faced with a number of intractable modern challenges that can be understood in terms of hyper-intellectualization; a compassion crisis, burnout, dehumanization, and lost meaning. These challenges have roots in medical philosophy and indeed general Western philosophy by way of the historic exclusion of human emotion from human reason. The resolution of these medical challenges first requires a novel philosophic schema of human knowledge and reason that incorporates the balanced interaction of human intellect and human emotion. This schema of necessity requires a novel extension of dual-process theory into epistemology in terms of both intellect and emotion each generating a distinct natural kind of knowledge independent of the other as well as how these two forms of mental process together construct human reason. Such a novel philosophic schema is here proposed. This scheme is then applied to the practice of medicine with examples of practical applications with the goal of reformulating medical practice in a more knowledgable, balanced, and healthy way. This schema's expanded epistemology becomes the philosophic foundation for more fully incorporating the humanities in medicine.

Errors in clinical diagnosis: a narrative review

Diagnostic errors are often caused by cognitive biases and sometimes by other cognitive errors, which are driven by factors specific to clinicians, patients, diseases, and health care systems. An experienced clinician diagnoses routine cases intuitively, effortlessly, and automatically through non-analytic reasoning and uses deliberate, cognitively effortful analytic reasoning to diagnose atypical or complicated clinical cases. However, diagnostic errors can never be completely avoided. To minimize the frequency of diagnostic errors, it is advisable to rely on multiple sources of information including the clinician's personal experience, expert opinion, principals of statistics, evidence-based data, and well-designed algorithms and guidelines, if available. It is also important to frequently engage in thoughtful, reflective, and metacognitive practices that can serve to strengthen the clinician's diagnostic skills, with a consequent reduction in the risk of diagnostic error. The purpose of this narrative review was to highlight certain factors that influence the genesis of diagnostic errors. Understanding the dynamic, adaptive, and complex interactions among these factors may assist clinicians, managers of health care systems, and public health policy makers in formulating strategies and guidelines aimed at reducing the incidence and prevalence of the phenomenon of clinical diagnostic error, which poses a public health hazard.

Diagnostic Evaluation of Stroke Etiology

OBJECTIVE

Precise therapies require precise diagnoses. This article provides an evidence-based approach to confirming the diagnosis of ischemic stroke, characterizing comorbidities that provide insights into the pathophysiologic mechanisms of stroke, and identifying targets for treatment to optimize the prevention of recurrent stroke.

LATEST DEVELOPMENTS

Identifying the presence of patent foramen ovale, intermittent atrial fibrillation, and unstable plaque is now routinely included in an increasingly nuanced workup in patients with stroke, even as ongoing trials seek to clarify the best approaches for treating these and other comorbidities. Multicenter trials have demonstrated the therapeutic utility of patent foramen ovale closure in select patients younger than age 60 years. Insertable cardiac monitors detect atrial fibrillation lasting more than 30 seconds in about one in ten patients monitored for 12 months following a stroke. MRI of carotid plaque can detect unstable plaque at risk of being a source of cerebral embolism.

ESSENTIAL POINTS

To optimize the prevention of recurrent stroke, it is important to consider pathologies of intracranial and extracranial blood vessels and of cardiac structure and rhythm as well as other inherited or systemic causes of stroke. Some aspects of the stroke workup should be done routinely, while other components will depend on the clinical circumstances and preliminary testing results.

Improving diagnosis: adding context to cognition

BACKGROUND

The environment in which clinicians provide care and think about their patients is a crucial and undervalued component of the diagnostic process.

CONTENT

In this paper, we propose a new conceptual model that links work conditions to clinician responses such as stress and burnout, which in turn impacts the quality of the diagnostic process and finally patient diagnostic outcomes. The mechanism for these interactions critically depends on the relationship between working memory (WM) and long-term memory (LTM), and ways WM and LTM interactions are affected by working conditions.

SUMMARY

We propose a conceptual model to guide interventions to improve work conditions, clinician reactions and ultimately diagnostic process, accuracy and outcomes.

OUTLOOK

Improving diagnosis can be accomplished if we are able to understand, measure and increase our knowledge of the context of care.