CPC Competition

Preparing and Presenting an Emergency Medicine

Clinical Pathologic Case Conference (CPC)

Michael Bhorn, MD
Chair, CPC Committee
York Hospital
York, PA

Abstract

The Clinical Pathologic Case Presentation (CPC) conference is a teaching tool that illustrates the logical, measured consideration of a differential diagnosis used to evaluate patients in the Emergency Department. Cases for presentation must be relevant to emergency medicine practice, solvable and discussible. Critical to this educational format’s success is an effective presentation by both the case presenter and the case discussant. Cases are discussed using logical consideration of their salient features and measured consideration of the suggested differential diagnosis. This paper reviews the preparation and presentation of the CPC conference for Emergency Medicine.

Introduction

The Clinical Pathological Case (CPC) conference for Emergency Medicine may be an effective teaching tool if presented appropriately. Not only does this conference format teach the clinical aspects of the presented case; it illustrates the logical, measured consideration of a differential diagnosis that typifies a rational approach to the ED patient. The inclusion of the CPC conference during Emergency Medicine meetings is testament to its educational value. The CPC conference can also be an effective way to teach medical students and Emergency Medicine residents, particularly when the learner is given the opportunity to prepare and present the discussion for a case from the faculty who present the case.

The CPC conference format mirrors the typical ED patient encounter. The presenter describes the patient’s chief complaint, history of present illness, past medical/surgical history, social history, allergies, and medications. The vital signs and physical examination are presented in sufficient detail. Diagnostic data usually available in the typical ED is presented. This might include pulse oximetry, basic laboratory tests, radiographs, electrocardiograms and other selected studies. The discussant then describes the differential diagnosis, logically narrowing the list to a few selected probable diagnoses and often offers a final diagnosis. The first presenter then reveals the final diagnosis, discusses how the diagnosis was confirmed, provides details regarding the case outcome, the applicability to Emergency Medicine, and may briefly discuss the final diagnosis. 

Time Line for CPC Presentation:

Resident Presenter - 5 Minutes
Faculty Discussant - 20 Minutes
Resident Presenter - 10 Minutes

The purpose of this paper is to describe the preparation and presentation of a clinical pathological case conference. The type of case selected is an important determinant of the presentation’s effectiveness. Selecting a case is discussed in detail. Effective preparation of the presentation and discussion of the case is reviewed.

Selecting a case for the CPC conference

Given the variety of cases seen in a typical Emergency Department, the spectrum of potential CPC cases is broad. Cases that are unusual presentations of common diagnoses or typical presentations of unusual diagnoses make the best cases for CPC presentation. The best cases for CPC conference have several elements in common: "relevance", "solvability", and "discuss-ability". Cases in which the final diagnosis is deduced, or highly suspected, based upon information available in the ED are considered "relevant". Although diagnostic evaluations not usual to the ED may be required to confirm the diagnosis, they should not be required to place the diagnosis at, or near, the top of the list of probable diagnoses. "Relevance" is linked to a critical element of an appropriate case: "solvability". The discussant must have a reasonable opportunity to make, deduce, or highly suspect the final diagnosis. Enough discriminating information must be available to allow a thoughtful, logical discussion of the differential diagnosis. Cases that are highly complex, contain multiple primary diagnoses, or are laden with many extraneous facts are difficult to solve and are avoided. Finally, the case must be "discuss-able". Cases that do not allow a demonstration of the deductive process used to reach a diagnosis do not afford the opportunity to teach the audience to think logically. Select cases that have interesting and educational differential diagnoses.

Preparing and presenting the case

After an appropriate case is selected, prepare it for presentation. Include the chief complaint, the history of present illness, past medical and surgical histories, social histories, medications, and allergies. Provide the vital signs and physical examination at an appropriate level of detail. If diagnostic studies were obtained, present the results. Do not interpret data. Let the discussant interpret the EKG, read the chest x-ray or calculate the anion gap. The contextual interpretation of data is an important part of the CPC discussion. It is customary to present all information obtained in the ED, usually in the order in which it was collected. Let the discussant decide which bits of information are relevant and which are "red herrings". Incomplete and irrelevant historical and physical examination data are part of the practice of Emergency Medicine. On rare occasion, it may be appropriate to withhold a confirmatory test obtained in the ED as long as the case is solvable based upon the other information provided. The goal of this academic exercise is not to "stump" the discussant but to present an interesting and educational conference.

The case information sent to the discussant is presented in the CPC conference. Present to the audience the information given to the presenter. For the sake of time, normal diagnostic data may be described as such without listing each result. Do not provide information to the audience that has not been given to the discussant. Do not interpret data for the audience; allow the discussant to interpret data. Present the case, clearly, concisely, and succinctly. Conclude the case presentation and offer the floor to the discussant. This should take no longer than 5 minutes.

Discussing a case in a CPC conference

Preparing for the conference

Discussing an unknown case in front of an audience can be stressful, but exciting and challenging. Adequate preparation for the discussion will make the presentation enjoyable. Remember the main goal of the CPC conference: illustrating the measured, logical progression from a patient presentation to a narrowed differential diagnosis. Do not focus on making a final diagnosis, focus on the process by which final diagnosis is derived. The process that led the discussant to the final diagnosis is illustrated in the CPC conference.

Review the case and consider each data point to be potentially relevant. Seemingly inconsequential information may prove to be pivotal. Determine which features of the case are the most relevant. These salient features may include historical and physical data, diagnostic data, and the interpretation of diagnostic data. Each salient feature prompts a differential diagnosis. Consider a complete differential diagnosis for each feature. The old saw "If you don’t think of it, you’ll never diagnose it" applies to CPC discussions. After outlining the potential diagnoses, narrow the list.

As in clinical medicine, one of two approaches often leads to a reasonable approximation of the final diagnosis. The first approach is to recognize the data as part of a syndrome. A syndrome is a constellation of signs, symptoms and diagnostic data related to another by some anatomic, physiologic or biochemical abnormality. Compare the differential diagnosis lists developed for each salient feature with each other. Occasionally, a common thread, or syndrome, is discovered. The table below illustrates this process:

 

Differential diagnosis A

Differential diagnosis B

Differential diagnosis C

Differential diagnosis D

Disease A

Disease F

Disease B

Disease W

Disease B

Disease I

Disease Q

Disease Z

Disease C

Disease P

Disease T

Disease M

Disease D

Disease R

Disease O

Disease X

Disease E

Disease B

Disease K

Disease B

 

 

In this example, diagnosis "B" is on each list and may represent a syndrome. Most cases will not be so straightforward. Disease "B" may not be contained on every list or a second syndrome may be common to many lists. When more than one syndrome is possible, weigh each diagnostic possibility with respect to the presence of "syndrome defining" features. Successive approximation will suggest that one diagnosis is more probable than another is.

The second approach weighs each potential diagnosis in terms of supporting or refuting data. Create a differential diagnosis list for each salient feature. Compare each list to find diseases common to one or more of them. The second example illustrates this process:

 

Differential diagnosis A

Differential diagnosis B

Differential diagnosis C

Differential diagnosis D

Disease A

Disease D
Disease B

Disease E

Disease B

Disease E

Disease Q

Disease Z

Disease C

Disease P
Disease P
Disease D
Disease D

Disease R

Disease O

Disease X

Disease E

Disease B

Disease E

Disease B

 

 

In this example, diseases "B" and "E" are on every list, disease "D" is on three lists, and disease "P" is on two lists. All other diseases are found only one time. The diseases common among several lists represent the most probable diagnoses. Consider clinical and diagnostic data that increases or decreases the probability that a diagnosis is correct. This table illustrates that process:

 

 

Data supporting

The diagnosis

Data not supporting

The diagnosis

Disease B

+ + + +

+ + + + + + + +

Disease E

+

+ + +

Disease D

+ + + + +

+ +

Disease P

+ +

+ + + + + + + +

 

 

In this example, disease "D" seems more probable than other diseases. Although disease "B" and disease "E" appeared on every list, the weight of the data does not make the diagnosis probable. Some data is more specific and may weigh more than other softer data. The discussant logically weighs each potential diagnosis in terms of the data available to estimate a probability. The most probable diagnosis will be at the top of the final differential diagnosis list, the least probable at the bottom.

Formatting the CPC discussion

Various presentation formats are effective and must suit the style of the discussant. Close attention to time guidelines is critical. The presentation format for the discussion could follow this outline:

  • Review of the salient features
  • Differential diagnosis of the salient features
  • Logical discussion of the potential diagnoses
  • Presentation of the most likely diagnoses
  • Potential confirmatory studies
  • Final diagnosis (if possible).

The discussion should take no longer than 20 minutes.

Presenting the final diagnosis and case discussion

After the discussant offers a potential solution to the case, the conference is returned to the presenter. The goals of this portion of the CPC conference are to: reveal the final diagnosis, present diagnostic data that confirms the diagnosis, discuss the diagnosis and its applicability to Emergency Medicine, and summarize the features of the case which allow a reasonable guess at the diagnosis.

Some may prefer to reveal the final diagnosis first and then offer data that confirmed the diagnosis. Others may prefer to describe the diagnostic test results before the final diagnosis is revealed. A brief discussion of the ED or hospital course and case outcome is informative and interesting. The order in which this information is presented is a matter of personal preference. Present a brief discussion of the final diagnosis that reviews the salient features of the diagnosis. Briefly summarize the Emergency Department stabilization and treatment. Since important aspects of the selected case were relevance and solvability, the presenter should reiterate the case’s relevance and solvability to the audience. Accomplish this by pointing out the historical, physical or diagnostic data points that would prompt a practicing Emergency Physician to suspect the final diagnosis. This part of the conference provides an important summary of the educational value of the CPC conference. This final segment of the CPC should take no longer than 10 minutes.

Presentation skills in the CPC conference

Good presentation skills are required of the case presenter and the case discussant. The participants must be well prepared and well rehearsed. The time of each segment of the CPC conference is often restricted. Always adhere to the time limits set for the conference. Speakers must be dressed appropriately and present themselves in a professional manner. If audiovisual equipment is used, it must work properly. Presenters should be comfortable with the equipment. If slides are projected, they must conform to accepted guidelines. Avoid crowded slides, irrelevant artwork, spelling errors, and distracting color schemes. The audience expects the participants to avoid monotonous speech, mumbling, distracting mannerisms, meaningless phrases and interjections, and a motionless presentation. The speakers must be engaging and enthusiastic. Humor may be a useful adjunct to the presentation but is used with caution. Do not tell inappropriate jokes or offend members of the audience.

Summary

The CPC conference can be a valuable education tool that accomplishes two distinct educational tasks. The first is to review and discuss the historical, physical and diagnostic data points of an Emergency Medicine case. Second and most importantly, the logical, deductive process used in clinical Emergency Medicine to winnow a long list of potential diagnoses to the most probable diagnosis is demonstrated. This is also a wonderful opportunity for residents and faculty to make a presentation during a national meeting. Presenters and discussants are encouraged to collaborate and submit cases for publication.

 

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