How to Develop a Differential Diagnosis

You and your colleagues have been asked to work together to create a differential diagnosis for Ella Cruz, prioritize your diagnoses, and propose tests that will help you test the diagnoses in your differential.

For this task, you should begin by gathering information on Ella’s signs and symptoms from the patient interview video and the additional findings from her Patient Interview Form. Then you should research what those signs and symptoms mean. Your research will help you create a differential diagnosis, and a plan for testing the items in the differential. Finally, together with your team, you need to complete the Differential Diagnosis Form, capturing not only which diagnoses are under consideration in order of likelihood, but also what tests you will recommend Dr. Campbell order to further hone the diagnosis.

The steps below will walk you through this process.

1. Meet with your team. Contact your mentor with questions about your team assignment.
• You may want to review the General Skills Resources link in the left menu for information on successfully forming a team.
• Your team may choose to have a team leader or may decide to have a different team structure. The choice is yours.
  
  
2. Review the email from Dr. Campbell to confirm your understanding of the task.
   
   
3. Download and review the Differential Diagnosis Form attached to Dr. Campbell's email both to see what is there and get a feel for what resources/templates you have available to you in this task.
   
   
4. Watch the patient interview video. Take notes, writing down any any clinical findings. Clinical findings are signs, symptoms, and test results, all of which give you information to help you make a diagnosis.
   1. As you watch the video notice any signs you see in the patient. How does she look? What, if any, are the outwardly visible indicators that she has a medical problem?
      
      
   2. Also pay attention to the patient's symptoms (the things she and her mother tell you she is experiencing). How does she feel? What's bothering her? What brought her into the emergency room today?
      
      
   3. Feel free to watch the video as many times as you need to feel comfortable with what you have seen.
      
5. Review Ella’s chart.
• Take any additional notes to expand upon the items you noted from the video.
  
  
• For any terms or phrases that are unfamiliar to you, look first in the Diagnosis and Treatment Archive (DATA) in the Resources link (above). If you cannot find it there, conduct some research of your own either online or using other resources.
  
  
6. When you feel ready to learn how to develop a diagnosis, download and review the Develop a Diagnosis and Treatment Process document in the Resources link (above). This document is a reference that outlines the complete process of diagnosing and treating a patient.
• Pay special attention to Steps 1, 2 and 3. They are the steps you will work on in this task.
  
  
7. Using the Diagnosis and Treatment Archive (DATA) in the Resources link (above), research each clinical finding you have identified. Please note: DATA is not intended to be a comprehensive database of all possible diagnoses for Ella's symptoms, but rather a condensed sampling of the most likely diagnoses. In the real world, physicians have familiarity with a broad and deep catalog of knowledge, and can access relevant details at a moment's notice. DATA has been created as a subset of relevant information for ease of information gathering and research, and cannot be compared to the complexity or richness of a physician's database -- his or her brain.

1. Look up each sign, symptom, and test result you learned about from Ella Cruz’s exam. Read about what they each mean and what problems (diagnoses) might be causing them. Take notes as you research each clinical finding.
   
   
2. Then look up the diagnoses that match up with the clinical findings that you have researched. Read through to see if the clinical findings associated with each diagnosis seem to describe what Ella is experiencing. Take notes as you research each relevant diagnosis.
   
   
3. As always, for any additional information that you cannot find within the database, feel free in conducting some research of your own either online or elsewhere.
   • Be on the alert to make sure that the sites you utilize are reputable sources.
     
     
1. Make a prioritized list, using the Differential Diagnosis Form, of the diagnoses that match up to Ella's clinical findings.
• This list is your differential diagnosis. to prioritize it, put the most likely and most life-threatening diagnosis at the top of the list, and the least likely at the bottom.
  
  
• When determining priority, consider the evidence for and against each diagnosis.
  
  
• It is very likely that you will not have much evidence to discriminate between diagnoses at this point; in this case, you consider the most dangerous or life-threatening diagnoses to be the highest priority.
  
  
• It is possible you might have one diagnosis that seems most comprehensive and reasonable. If that happens, it is fine. However you will need to include a few alternative diagnoses to fall back on if your tested diagnosis comes up negative (meaning the patient doesn't have that illness).
  
  
2. Determine appropriate tests. As you consider various diagnoses or causes of the various clinical findings, research how to test to confirm or disconfirm your suspected diagnoses. Track the test names and how they are relevant in the Differential Diagnosis Form.
   
   
3. Review the Tips and Traps by clicking the link at the top of this page. Carefully read each suggestion and make sure you are on the right track.
   
   
4. Review your work.
   • Did you develop a list of possible diagnoses based on Ella’s symptoms?
     
     
   • Did you prioritize them according to the most likely or life-threatening to the least likely or life-threatening?
     
     
   • Have you identified tests that will confirm or disconfirm the diagnoses in your prioritized differential, and defended the need for those tests?
     
     
5. Submit your work.
   • Review the checklist located in the Submit Your Work section of this task and submit the assignment to your mentor.

Getting Started

1. Work with your team to decide how you will approach this assignment. Create a work plan that shows how you will divide up your work. It is important to have a plan of attack!
   
   
2. Review all the materials thoroughly before you start filling out the Differential Diagnosis Form (i.e., emails, video, step-by-step instructions, templates, resources, etc.). Make sure you understand what you are being asked to do. If you have questions, contact your mentor.
   

Gathering Clinical Findings

1. Some signs might be the same as the symptoms. If the patient talks about something you can see, write it down as a sign. You don't need to list it more than once.
   
   
2. The patient's history can be as important as her signs and symptoms. Listen carefully when she describes her background. Think about the impact her history may have on her current condition.
   

Using DATA

1. When you are working in the Diagnosis and Treatment Archive (DATA), you may find that the clinical findings are not listed exactly as you noted them from the patient examination. Look for entries on the Clinical Findings list that are close to what you have written in your notes. You may need to be creative and think about different ways to say the same thing: e.g., a bruise may also be called a skin discoloration.
   
   
2. When you are using the DATA, some of the links might present information written in fairly advanced language. Don't be discouraged if you have trouble understanding it right away. Work slowly. Discuss the information with your group. It may even help you to read the material out loud. If you and your team cannot understand something that you believe may be important, feel free to contact your mentor for support.
   

Developing a Differential Diagnosis

1. You should develop a differential diagnosis by looking for common denominators in your notes. For example, if through your research you learn that every sign or symptom you have identified can be caused by a heart problem, then a heart problem should be one of the diagnoses in your differential, and perhaps it should be given a high priority.
   
   
2. If a diagnosis explains only one of the patient's signs or symptoms but does not explain the others, try to find a diagnosis that explains more than one, and if possible, all of them.

A patient may have multiple conditions at one time causing several unrelated signs and symptoms. When that is the case, each problem requires its own treatment. Often, though, if a patient complains of multiple signs and symptoms at one time, there is one cause/diagnosis that results in numerous signs and symptoms.

For example, not drinking enough water can be the cause of a person feeling hungry, tired, and dizzy (all symptoms of dehydration). By treating the root of the problem rather than each individual symptom, you can eliminate further complications.

Checking Your Work

1. If you determine that a diagnosis in your differential is highly likely, you may be tempted to go a step further and try to determine the cause of that problem. You are not being asked to do that in this task. You will get a chance to look at those causes, but for now, focus on explaining the symptoms.
   
   
2. When you recommend a test for a diagnosis, make sure to provide a rationale for how it will help you to confirm or disconfirm the diagnosis. What will it tell you about the organ or organ-system you think may be causing the patient's problematic signs and symptoms?
   

Diagnosis and Treatment Archive (DATA) - Mystery Case

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