Principles and Practice of Case-based Clinical Reasoning Education: A Method for Preclinical Students

Front matter

Innovation and Change in Professional Education 15

Olle ten Cate Eugene J.F.M. Custers Steven J. Durning Editors

Principles and Practice of Case-based Clinical Reasoning Education

Preface

Probably the most core characteristic of any physician is their clinical reasoning ability as it touches all aspects of patient care. While this statement is not disputed, the education to support students in acquiring this ability is far from clear. Clinical reasoning has been the subject of substantial research to (1) clarify what it actually is; (2) identify when and why clinical reasoning goes wrong, resulting in errors or suboptimal care; (3) identify teaching approaches; and (4) recognize models of assessment. While some medical education scholars question whether clinical reasoning can be explicitly taught at all, the literature provides many teaching methods. None of these are conclusive and every medical school has their own way to support medical students in their development of clinical reasoning ability.

One area where there is agreement in the medical education community, based on a body of empirical work, is that clinical experience and a substantial knowledge base are necessary to reach high levels of clinical reasoning ability. Schools desiring to optimally prepare students for their clinical experiences face a difficult problem. How to best train students to think like a doctor? Can they learn taking histories and conducting physical examinations, formulating differential diagnoses, and proposing management plans before they enter the clinical arena? Integrated curricula, particularly in a vertical sense, attempt to combine basic science teaching with patient-based clinical teaching at early stages of the medical curriculum to optimize this preparation. But what if clinical experience itself is necessary to begin acquiring clinical reasoning ability?

This book describes a teaching method that has been used for over 20 years and has survived multiple medical curricula in different educational institutions in the Netherlands and other countries. The method is derived from the primary editor’s Ph.D. studies on peer teaching in the 1980s at the University of Amsterdam Medical School.

In the past 10 years, the model has been used to support the modernization of medical curricula through EU-funded projects in Moldova, Georgia, Azerbaijan, and Ukraine. The most recent of these projects (MUMEENA or Modernizing Undergraduate Medical Education in the Eastern Neighboring Area) has led to a detailed, extensive description of the case-based clinical reasoning (CBCR) method vi Preface that was first published as a gray-literature English language book and subsequently translated in the Georgian, Azeri, Ukrainian, and Spanish languages.

This volume was fully revised and expanded, resulting in the current publication.

The CBCR educational method is one approach to preparing students to think like doctors before they become engaged in patient care. We do not claim that it is the only (or even the preferred) method. What we can say is that this method has served many generations (thousands of medical students) in their preclinical period. Available student evaluations have been consistently as good as or better than other preclinical courses. The method can be applied within or added to an existing medical curriculum, as a core, elective, or extracurricular course.

The book has three parts. For readers interested in general understanding of clinical reasoning education, Part I (Chaps. 1, 2, 3, 4, and 5) will provide food for thought. For those interested to apply the CBCR method, Part II (Chaps. 6, 7, 8, 9, and 10) is recommended. Part III (the appendices) provides cases that can be used, for instance, by educators who wish to try out this method with their learners.

We wish to thank the many individuals who have contributed to the success of the CBCR method by being involved in the initial design, notably Professor Bert Schadé from the Academic Medical Center in Amsterdam, or by serving as consultants and by writing cases. For this volume, we thank Drs. Charles Magee, Mary Kwok, Jeremy Perkins, and Lieke van Imhoff for writing or editing one or more cases included in the appendix.

Utrecht, The Netherlands Olle ten Cate Utrecht, The Netherlands Eugène J.F.M. Custers Bethesda, MD, USA Steven J. Durning

Part I Backgrounds of Educating Preclinical Students in Clinical Reasoning

2 Training Clinical Reasoning: Historical Eugène J.F.M. Custers

3 Understanding Clinical Reasoning from Multiple Perspectives: Olle ten Cate and Steven J. Durning

Judith L. Bowen and Olle ten Cate

5 Approaches to Assessing the Clinical Reasoning Olle ten Cate and Steven J. Durning

Part II The Method of Case-Based Clinical Reasoning Education Angela van Zijl, Maria van Loon, and Olle ten Cate

Olle ten Cate

S Writing (BOCK Case u. u. egw beree Orea rE EEROR EEE Olle ten Cate and Maria van Loon

Vili Contents

9 Curriculum, Course, and Faculty Development Olle ten Cate and Gaiane Simonia

Maria van Loon, Sjoukje van den Broek, and Olle ten Cate

Editors and Contributors

About the Editors

Olle ten Cate, Ph.D. is a professor of medical education and director of the Center for Research and Development of Education at University Medical Center Utrecht, The Netherlands. He was the originator and has been intermittently coordinator of CBRC courses from 1993 until 1999 in Amsterdam and from 2005 until 2016 in Utrecht. His research and development interests include curriculum development, peer teaching, competency-based medical education, clinical reasoning, and many other areas.

Eugène J.F.M. Custers, Ph.D. is a researcher in medical education at the Center for Research and Development of Education at University Medical Center Utrecht, The Netherlands. His primary area of expertise is clinical reasoning, the role of basic sciences in medical expertise, and illness script development. He also has a special interest in the history of medical education.

Steven J. Durning, M.D., Ph.D. is professor of medicine and pathology and director for the graduate programs in health professions education, the Introduction to Clinical Reasoning medical school course, and the Long-Term Career Outcome Study at the Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA. He holds a Ph.D. in health professions education and is a practicing internist. His research and development interests include clinical reasoning, assessment, educational theory, peer teaching, and several other areas.

x Editors and Contributors

About the Contributors

Judith L. Bowen, M.D. is professor of medicine in the Division of General Internal Medicine and Geriatrics, Oregon Health and Science University, Portland, Oregon, USA, where she directs the Education Scholars Program, a longitudinal faculty development program for clinical teachers. She is a Ph.D. candidate in medical education at Utrecht University. Her research interests include clinical reasoning and curriculum with a focus on the impact of transitions of clinical responsibility on learning diagnostic reasoning.

Gaiane Simonia, M.D., Ph.D. is professor of internal medicine, head of the Division of Geriatrics, and head of the Department of Medical Education, Research and Strategic Development at Tbilisi State Medical University, Tbilisi, Georgia. She was involved as primary initiator of the MUMEENA project of modernizing medical education in Eastern European countries which included the introduction of CBCR in curricula in Georgia, Azerbaijan, and Ukraine.

Sjoukje van den Broek, M.D. is an assistant professor at the Unit of Medical Education, with an adjunct attachment with the Center for Research and Development of Education, both at University Medical Center Utrecht, The Netherlands. She has been involved with CBCR from 2010 as consultant and is currently a coordinator of the CBCR course for second-year medical students. She is also a Ph.D. candidate in medical education, and she supports, as general secretary, the Ethical Review Board for Health Professions Education Research of The Netherlands Association for Medical Education.

Maria van Loon, M.D. worked as a junior teacher at the Center for Research and Development of Education, University Medical Center Utrecht, The Netherlands. She was involved with CBCR in 2014 as a consultant and as a coordinator of the CBCR course for second-year medical students and was actively involved with the training of medical schools with CBCR in Georgia, Azerbaijan, Ukraine, and Spain. She now works as a resident in general practice at University Medical Center Utrecht.

Angela van Zijl, M.D. worked as a junior teacher at the Center for Research and Development of Education, University Medical Center Utrecht. She was involved with CBCR in 2013 as a coordinator of the CBCR course for second-year medical students and was actively involved with the training of medical schools with CBCR in Azerbaijan. At the moment, she is a resident in pediatrics at Gelderse Vallei Hospital Ede, The Netherlands.

Part I Backgrounds of Educating Preclinical Students in Clinical Reasoning

Chapter 1 Introduction Olle ten Cate

Clinical reasoning is a professional skill that experts agree is difficult and takes time to acquire, and, once you have the skill, it is difficult to explain what you actually do when you apply it—clinical reasoning then sometimes even feels as an easy process. The input, a clinical problem or a presenting patient, and the outcome, a diagnosis and/or a plan for action, are pretty clear, but what happens in the doctor’s mind in the meantime is quite obscure. It can be a very short process, happening in seconds, but it can also take days or months. It can require deliberate, painstaking thinking, consultation of written sources, and colleague opinions, or it may just seem to happen effortless. And “reasoning” is such a nicely sounding word that doctors would agree captures what they do, but is it always reasoning? Reasoning sounds like building a chain of thoughts, with causes and consequences, while doctors sometimes jump at a conclusion, sometimes before they even realize they are clinically reasoning. Is that medical magic? No, it’s not. Laypeople do the same. Any adult witnessing a motorcycle accident and seeing a victim on the street showing a lower limb in a strange angle will instantly “reason” the diagnosis is a fracture. Other medical conditions are less obvious and require deep thinking or investigations or literature study. Whatever presentation, doctors need to have the requisite skills to tackle the medical problems of patients that are entrusted to their care. No matter how obscure clinical reasoning is, students need to acquire that ability. So how does a student begin to learn clinical reasoning? How must teachers organize the training of students?

Case-based clinical reasoning (CBCR) education is a design of training of preclinical medical students, in small groups, in the art of coping with clinical problems as they are encountered in practice. As will be apparent from the description

O. ten Cate (J) Center for Research and Development of Education, University Medical Center Utrecht, Utrecht, The Netherlands

© The Author(s) 2018 3 O. ten Cate et al. (eds.), Principles and Practice of Case-based Clinical

Reasoning Education, Innovation and Change in Professional Education 15, https://doi.org/10.1007/978-3-3 19-64828-6_1 later in this chapter, CBCR is not identical to problem-based learning (Barrows and Tamblyn 1980), although some features (small groups, no traditional teacher role) show resemblance. While PBL is intended as a method to arrive at personal educational objectives and subsequently acquire new knowledge (Schmidt 1983), CBCR has a focus on training in the application of systematically acquired prior knowledge, but now in a clinical manner. It aims at building illness scripts—mental representations of diseases—while at the same time supports the acquisition of a diagnostic thinking habit. CBCR is not an algorithm or a heuristic to be used in clinical practice to efficiently solve a new medical problem. CBCR is no more and no less than educational method to acquire clinical reasoning skill. That is what this book is about.

The elaboration of the method (Part II and III of the book) is preceded in Part I by chapters on the general background of clinical reasoning and its teaching.

What Is Clinical Reasoning?

Clinical reasoning is usually defined in a very general sense as “The thinking and decision -making processes associated with clinical practice” (Higgs and Jones 2000) or simply “diagnostic problem solving” (Elstein 1995).

For the purpose of this book, we define clinical reasoning as the mental process that happens when a doctor encounters a patient and is expected to draw a conclusion about (a) the nature and possible causes of complaints or abnormal conditions of the patient, (b) a likely diagnosis, and (c) patient management actions to be taken. Clinical reasoning is targeted at making decisions on gathering diagnostic information and recommending or initiating treatment. The mental reasoning process is interrupted to collect information and resumed when this information has arrived.

It is well established that clinicians have a range of mental approaches to apply. Somewhat simplified, they are categorized in two thinking systems, sometimes subsumed under the name dual-process theory (Eva 2005; Kassirer 2010; Croskerry 2009; Pelaccia et al. 2011). Based in the work of Croskerry (2009) and the Institute of Medicine (Balogh et al. 2015), Fig. 1.1 shows a model of how clinical reasoning and the use of System 1 and 2 thinking can be conceptualized graphically.

The first thinking approach is rapid and requires little mental effort. This mode has been called System 1 thinking or pattern recognition, sometimes referred to as non-analytical thinking. Pattern recognition happens in various domains of expertise. Based on studies in chess, it is estimated that grand master players have over 50,000 patterns available in their memory, from games played and games studied (Kahneman and Klein 2009). These mental patterns allow for the rapid comparison of a pattern in a current game with patterns stored in memory and for a quick decision which move to make next. This huge mental library of patterns may be compared with the mental repository of illness scripts that an experienced clinician has and that allows for the rapid recognition of a pattern of signs and symptoms in a

Illness scripts in long-term — _ ~ memory _

System 1 thinking

Pattern L recognized Hypothesis > z Patient Pattern ——,IKIQ O testingand | c= Diagnosis and i + ` management presentation processor diagnostic 3 EEE decision verification Pattern not Causality recognized — | construction

System 2 thinking Causal reasoning and biomedical - ~ knowledge eam

Fig. 1.1 A model of clinical reasoning (Adapted from Croskerry 2009)

Box 1.1 Illness Script

An illness script is a general representation in the physician’s mind of an illness. An illness script includes details on typical causal or associated preceding features (“enabling conditions”); the actual pathology (“fault”); the resulting signs, symptoms, and expected diagnostic findings (“consequences”); and, added to the original illness script definition (Feltovich and Barrows 1984), the most likely course and prognosis with suitable management options (“management”). An illness script may be stored as one comprehensive unit in the long-term memory of the physician. It can be triggered to be retrieved during new clinical encounters, to facilitate comparison and contrast, in order to generate a diagnostic hypothesis.

patient with patients encountered in the past (Feltovich and Barrows 1984; Custers et al. 1998). See Box 1.1.

A mental matching process can lead to an instant recognition and generation of a hypothesis, if sufficient features of the current patient resemble features of a stored illness script.

Next to this rapid mental process, clinicians use System 2 thinking: the analytical thinking mode of presumed causes-and-effects reasoning that is slow and takes effort and is used when a System 1 process does not lead to an acceptable proposition to act. Analytic, often pathophysiological, thinking is typically the approach that textbooks of medicine use to explain signs and symptoms related to pathophysiological conditions in the human body. Both approaches are needed in clinical health care, to arrive at decisions and actions and to retrospectively justify actions taken. The two thinking modes can be viewed on a cognitive continuum between instant recognition and a reasoning process that may take a long time (Kassirer et al. 2010; Custers 2013). In routine medical practice, the rapid System 1 thinking prevails. This thinking often leads to correct decisions but is not infallible. However, the admonition to slow down the thinking when System | thinking fails and move to System 2 thinking may not lead to more accurate decisions (Norman et al. 2014). In fact, emerging fMRI studies seem to indicate that in complex cases, inexperienced learners search for rule-based reasoning solutions (System 2), while experienced clinicians keep searching for cases from memory (System 1) (Hruska et al. 2015).

How to Teach Clinical Reasoning to Junior Students?

It is not exactly clear how medical students acquire clinical reasoning skills (Boshuizen and Schmidt 2000), but they eventually do, whether they had a targeted training in their curriculum or not. Williams et al. found a large difference in reasoning skill between years of clinical experience and across different schools (Williams et al. 2011). Even if reasoning skill would develop naturally across the years of medical training, it does not mean that educational programs cannot improve.

One way to approach the training of students in clinical reasoning is to focus on things that can go wrong in the practice of clinical reasoning and on threats to effective

Box 1.2 Summary of Prevalent Causes of Errors and Cognitive Biases Errors (Graber et al. 2005; Kassirer et al. 2010)

— Lack or faulty knowledge

— Omission of, or faulty, data gathering and processing — Faulty estimation of disease prevalence

— Faulty test result interpretation

— Lack of diagnostic verification

Biases (Balogh et al. 2015)

— Anchoring bias and premature closure (stop search after early explanation)

— Affective bias (emotion-based deviance from rational judgment)

— Availability bias (dominant recall of recent or common cases)

— Context bias (contextual factors that mislead)

thinking in clinical care. Box 1.2 shows the most prevalent errors and cognitive biases in clinical reasoning (Graber et al. 2005; Kassirer et al. 2010). See also Chap. 3.

In general, diagnostic errors are considered to occur too often in practice (McGlynn et al. 2015; Balogh et al. 2015), and it is important that student preparation for clinical encounters be improved (Lee et al. 2010). In a qualitative study, Audétat et al. observed five prototypical clinical reasoning difficulties among residents: generating hypotheses to guide data gathering, premature closure, prioritizing problems, painting an overall picture of the clinical situation, and elaborating a management plan (Audétat et al. 2013), not unlike the prevalent errors in clinical practice as summarized in Box 1.2. Errors in clinical reasoning pertain to both System 1 and System 2 thinking and cognitive biases causing errors are not easily amenable to teaching strategies. An inadequate knowledge base appears the most consistent reason for error (Norman et al. 2017). A number of authors have recommended tailored teaching strategies for clinical reasoning (Rencic 2011; Guerrasio and Aagaard 2014; Posel et al. 2014). Most approaches pertain to education in the clinical workplace. Box 1.3 gives a condensed overview.

One dominant approach that clinical educators use when teaching students to solve medical problems is ask them to analyze pathophysiologically, in other words to use System 2 thinking. While this seems the only option with students who do not

Box 1.3 Summary of Recommended Approaches to Teaching Clinical Reasoning (Guerrasio and Aagaard 2014; Rencic 2011; Posel et al. 2014; Chamberland et al. 2015; Balslev et al. 2015; Bowen 2006)

Let students

° Maximize learning by remembering many patient encounters.

° Recall similar cases as they increase experience.

° Build a framework for differential diagnosis using anatomy, pathology, and organ systems combined with semantic qualifiers: age, gender, ethnicity, and main complaint.

° Differentiate between likely and less likely but important diagnoses.

° Contrast diagnoses by listing necessary history questions and physical exam maneuvers in a tabular format and indicating what supports or does not support the respective diagnoses.

° Utilize epidemiology, evidence, and Bayesian reasoning.

e Practice deliberately; request and reflect on feedback; and practice mentally.

° Generate self-explanations during clinical problem solving.

° Talk in buzz groups at morning reports with oral and written patient data.

e Listen to clinical teachers reasoning out loud.

° Summarize clinical cases often using semantic qualifiers and create problem representations.

possess a mental library of illness scripts to facilitate System 1 thinking, those teachers teach something they usually do not do themselves when solving clinical problems This teaching resembles the “do as I say, not as I do” approach, in part because they simply cannot express “how they do” when they engaged in clinical reasoning.

In a recent review of approaches to the teaching of clinical reasoning, Schmidt and Mamede identified two groups of approaches: a predominant serial-cue approach (teachers provide bits of patient information to students and ask them to reason step by step) and a rare whole-task (or whole-case) approach in which all information is presented at once. They conclude that there is little evidence for the serial-cue approach, favored by most teachers and recommend a switch to whole-case approaches (Schmidt and Mamede 2015). While cognitive theory does support whole-task instructional techniques (Vandewaetere et al. 2014), the description of a whole-case in clinical education is not well elaborated. Evidently a whole-case cannot include a diagnosis and must at least be partly serial. But even if all the information that clinicians in practice face is provided to students all at once, the clinical reasoning process that follows has a serial nature, even if it happens quickly. Schmidt and Mamede’s proposal to first develop causal explanations, second to encapsulate pathophysiological knowledge, and third to develop illness scripts (Schmidt and Mamede 2015) runs the risk of separating biomedical knowledge acquisition from clinical training and regressing to a Flexnerian curriculum. Flexner advocated a strong biomedical background before students start dealing with patients (Flexner 1910). This separation is currently not considered the most useful approach to clinical reasoning education (Woods 2007; Chamberland et al. 2013).

Training students in the skill of clinical reasoning is evidently a difficult task, and Schuwirth rightly once posed the question “Can clinical reasoning be taught or can it only be learned?” (Schuwirth 2002). Since the work of Elstein and colleagues, we know that clinical reasoning is not a skill that is trainable independent of a large knowledge base (Elstein et al. 1978). There simply is not an effective and teachable algorithm of clinical problem solving that can be trained and learned, if there is no medical knowledge base. The actual reasoning techniques used in clinical problem solving can be explained rather briefly and may not be very different from those of a car mechanic. Listen to the patient (or the car owner), examine the patient (or the car), draw conclusions, and identify what it takes to solve the problem. There is not much more to it. In difficult cases, medical decision-making can require knowledge of Bayesian probability calculations, understanding of sensitivity and specificity of tests (Kassirer et al. 2010), but clinicians seldom use these advanced techniques explicitly at the bedside.

These recommendations are of no avail if students do not have background knowledge, both about anatomical structures and pathophysiological processes and about patterns of signs and symptoms related to illness scripts. When training medical students to think like doctors, we face the problem that we cannot just look how clinicians think and just ask students to mimic that technique. That is for two reasons: one is that clinicians often cannot express well how they think, and the second is simply that the huge knowledge base required to think like an experienced clinician is simply not present in students.

As System 1 pattern recognition is so overwhelmingly dominant in the clinician’s thinking (Norman et al. 2007), the lack of a knowledge base prohibits junior students to think like a doctor. It is clear that students cannot “recognize” a pattern if they do not have a similar pattern in their knowledge base. It is unavoidable that much effort and extensive experience are needed before a reasonable repository of illness scripts is built that can serve as the internal mirror of patterns seen in clinical practice. Ericsson’s work suggests that it may take up to 10,000 hours of deliberate practice to acquire expertise in any domain, although there is some debate about this volume (Ericsson et al. 1993; Macnamara et al. 2014). Clearly, students must see and experience many, many cases and construct and remember illness scripts. What a curriculum can try to offer is just that, i.e., many clinical encounters, in clinical settings or in a simulated environment. Clinical context is likely to enhance clinical knowledge, specifically if students feel a sense of responsibility or commitment (Koens et al. 2005; Koens 2005). This sense of commitment in practice relates to the patient, but it can also be a commitment to teach peers.

System 2 analytic reasoning is clearly a skill that can be trained early in a curriculum (Ploger 1988). Causal reasoning, usually starting with pathology (a viral infection of the liver) and a subsequent effect (preventing the draining of red blood cell waste products) and ending with resulting symptoms (yellow stains in the blood, visible in the sclerae of the eyes and in the skin, known as jaundice or icterus), can be understood and remembered, and the reasoning can include deeper biochemical or microbiological explanations (How does it operate the chemical degradation of hemoglobin? Which viruses cause hepatitis? How was the patient infected?). This basically is a systems-based reasoning process. The clinician however must reason in the opposite direction, a skill that is not simply the reverse of this chain of thought, as there may be very different causes of the same signs and symptoms (a normal liver, but an obstruction in the bile duct, or a normal liver and bile duct, but a profuse destruction of red blood cells after an immune reaction). So analytic reasoning is trainable, and generating hypotheses of what may have caused the symptoms requires a knowledge base of possible physiopathology mechanisms. That can be acquired step by step, and many answers to analytic problems can be found in the literature. But clearly, System 2 reasoning too requires prior knowledge. So both a basic science knowledge base and a mental illness script repository must be available.

The case-based clinical reasoning training method acknowledges this difficulty and therefore focuses on two simultaneous approaches (1) building illness scripts from early on in the curriculum, beginning with simple cases and gradually building more complex scripts to remember, and (2) conveying a systematic, analytic reasoning habit starting with patient presentation vignettes and ending with a conclusion about the diagnosis, the disease mechanism, and the patient management actions to be taken.

10 O. ten Cate Summary of the CBCR Method

When applying these principles to preclinical classroom teaching, a case-based approach is considered superior to other methods (Kim et al. 2006; Postma and White 2015). Case-based clinical reasoning was designed at the Academic Medical Center of University of Amsterdam in 1992, when a new undergraduate medical curriculum was introduced (ten Cate and Schadé 1993; ten Cate 1994, 1995). This integrated medical curriculum with multidisciplinary block modules of 6-8 weeks had existed since 10 years, but was found to lack a proper preparation of students to think like a doctor before entering clinical clerkships. Notably, while all block modules stressed the knowledge acquisition structured in a systematic way, usually based on organ systems and resulting in a systems knowledge base, a longitudinal thread of small group teaching was created to focus on patient-oriented thinking, with application of acquired knowledge (ten Cate and Schadé 1993). This CBCR training was implemented in curriculum years 2, 3, and 4, at both medical schools of the University of Amsterdam and the Free University of Amsterdam, which had been collaborating on curriculum development since the late 1980s. After an explanation of the method in national publications (ten Cate 1994, 1995), medical schools at Leiden and Rotterdam universities adopted variants of it. In 1997 CBCR was introduced at the medical school of Utrecht University with minor modifications and continued with only little adaptations throughout major undergraduate medical curriculum changes in 1999, 2006, and 2015 until the current day (2017).

CBCR can be summarized as the practicing of clinical reasoning in small groups. A CBCR course consists of a series of group sessions over a prolonged time span. This may be a semester, a year, or usually, a number of years. Students regularly meet in a fixed group of 10-12, usually every 3—4 weeks, but this may be more frequent. The course is independent of concurrent courses or blocks. The rationale for this is that CBCR stresses the application of previously acquired knowledge and should not be programmed as an “illustration” of clinical or basic science theory. More importantly, when the case starts, students must not be cued in specific directions or diagnoses, which would be the case if a session were integrated in, say, a cardiovascular block. A patient with shortness of breath would then trigger too easily toward a cardiac problem.

CBCR cases, always titled with age, sex, and main complaint or symptom, consist of an introductory case vignette reflecting the way a patient presents at the clinician’s office. Alternatively, two cases with similar presentations but different diagnoses may be worked through in one session, usually later in the curriculum when the thinking process can be speeded up. The context of the case may be at a general practitioner’s office, at an emergency department, at an outpatient clinic, or at admission to a hospital ward. The case vignette continues with questions and assignments (e.g., What would be first hypotheses based on the information so far? What diagnostic tests should be ordered? Draw a table mapping signs and symptoms against likelihood of hypotheses), at fixed moments interrupted with the provision of new findings about the patient from investigations (more extensive history, additional physical examination, or new results of diagnostic tests), distributed or read out loud by a facilitator during the session at the appropriate moment. A full case includes the complete course of a problem from the initial presentation to follow-up after treatment, but cases often concentrate on key stages of this course. Case descriptions should refer to relevant pathophysiological backgrounds and basic sciences (such as anatomy, biochemistry, cell biology, physiology) during the case.

The sessions are led by three (sometimes two) students of the group. They are called peer teachers and take turns in this role over the whole course. Every student must act as a peer teacher at multiple sessions across the year. Peer teachers have more information in advance about the patient and disclose this information at the appropriate time during the session, in accordance with instructions they receive in advance. In addition, a clinician is present. Given the elaborated format and case description, this teacher only acts as a consultant, when guidance is requested or helpful, and indeed is called “consultant” throughout all CBCR education.