Hansen Su, MD.
UMD/New Jersey Medical School

Medicase

ABSTRACT

The aim of Medicase is to simulate the patient interview: the history and physical, and subsequent testing and diagnosis. Students choose a case, are given the Chief Complaint, then are allowed to take a history by choosing from a set of questions. Only after completing the history is the student allowed to proceed with the interview, again by selecting from a bank of questions. Clinical tests can be ordered only after the interview is over. (Lab tests are shown with cost; and reasons to test.) This format is followed from hypothesis to final diagnosis. At completion, the student is given a point score.

PAPER

Hansen Su
Johns Hopkins University
Baltimore, MD		 Joseph Boyle, III, MD
Department of Physiology
NJ Medical School
Newark, NJ
Lavinia Kumar, EdD
Office of Education
NJ Medical School
Newark, NJ		 Kenneth J. Friedman, PhD
Department of Physiology
NJ Medical School
Newark, NJ

Introduction

MediCase 1.0 was designed to complement the didactic methods of teaching by utilizing case studies to reinforce basic or clinical principles. In creating this program, we addressed the challenge of devising software which provides a guided approach to problem solving by leading students through the clinical process of making a diagnosis. We also sought to develop an interesting way of presenting cases without the need for sophisticated programming knowledge on the part of the instructors while still giving the instructors full control over the material that is presented. Despite the initial intent of writing a program to specifically present problem-based-learning cases in cardiopulmonary physiology, this program can present numerous types of problems ranging from biochemistry to zoology, again, without the need for any elaborate programming.

Program Design

The structure of the program, although initially complex, allows the instructor the flexibility to present his or her own material in a highly organized fashion. Medicase 1.0 was written in Visual Basic ¨ and provides a number of screen templates and windows. These screen templates hold text or graphics files that are created by the instructor. Templates or windows are provided for the patient interview or history, the patient's photograph, present illness, past medical history, physical examination, laboratory test results, etc., as well as, special diagnostic tests presented as graphics (X-rays, CAT scans, EKG's, etc). These templates provide space for a large number of options such as questions during the patient's history, signs, symptoms, diagnostic tests and student feedback. These options can be customized by the instructor for each case. In addition, the instructor must provide the laboratory data, graphics files and diagnostic costs for each test.

The student is guided through the program by enabling only certain menu options at specific times during the presentation of the case. Thus, the student must first open a case, obtain a chief complaint and elicit the history of the present illness before proceeding to the physical examination or laboratory tests. The object of this problem solving exercise is to make the proper diagnosis using only an acceptable number of appropriate diagnostic tests. The student's score is maintained throughout the exercise as a motivating factor to perform well. Each phase of the exercise costs the "patient" money and the student points (or salary). Inappropriate tests penalize the student more than appropriate tests. To customize the program for each case, all of the data must be stored in an organized fashion. MediCase 1.0 was designed to read simple text files (ASCII) stored in specific sub-directories within a main directory, C:\MEDICASE. The program provides a batch file that sets up the directory and sub-directory structures that should allow the majority of cases to fit within the confines provided. Within C:\MEDICASE are the following five sub-directories which are shown in Figure 1.


Fig. 1 - MediCase Directory Tree

C:\MEDICASE\CASES - Contains all the necessary data for each case.
C:\MEDICASE\DISEASES - Contains data on diseases associated with the cases.
C:\MEDICASE\HELP - Contains help files.
C:\MEDICASE\SIGNS - Contains hints on related signs.
C:\MEDICASE\SYMPTOMS - Contains hints on related symptoms.

All of the files required for MediCase are stored in these sub-directories. From the diagram above, you can see how information, whether it be in the form of text files (*.txt) or graphic files (*.bmp) can be stored in a way that is specific to each case study.

A.) Cases

As the name of this directory implies, all the data for each case is stored here. Each case is given its own sub-directory (see diagram) and is distinguished by its number (case1, case2, case3, etc.,.). Thus, all data pertaining to Case #1 is stored, one way or another, in c:\medicase\cases\case1. From the tree diagram, you can see how the case data is organized in further sub-directories. Although this may take some getting used to, it is really a very precise and logical way of organizing case information without limiting flexibility on the part of the instructor. The list below is a basic explanation of the function of each sub-directory for each case:

INTERVIEW - Contains the following sub-directories for organizing patient interview information:

ILLNESS - Contains questions & answers regarding the present illness.
PASTHIST - Contains questions & answers regarding past history.
FAMHIST - Contains questions & answers regarding family history.

PHYSICAL - Contains the following sub-directories for organizing physical exam information:

AUSCULT - Contains names of auscultated regions and the results (*.wav files only).
OBSERVE - Contains names of observed regions and the results (*.txt files only).
PALPATE - Contains names of palpated regions and the results (*.txt files only).
GRAPHICS - Contains names & pictures of certain regions (*.bmp files only).

TESTS - Contains the following sub-directories for organizing various types of proper and improper tests that can be performed.

PROPER\GRAPHICS - Contains costs and titles of appropriate tests with results in bitmap form.
PROPER\TEXT - Contains costs and titles of appropriate tests with results in text form.
IMPROPER\GRAPHICS - Contains costs and titles of inappropriate tests with results in bitmap form.
IMPROPER\TEXT - Contains costs and titles of inappropriate tests with results in text form.

B.) Diseases

The student makes a final diagnosis from a list of diseases stored in this directory. The description of the diseases themselves are stored in this directory while the names of each one are located in the following sub-directory:
NAMES - Contains the names of each disease (*.txt files only).

C.) Help

This directory organizes the help files for MediCase. For the most part, the instructor will never have to go into this directory since the files in here pertain to how to use MediCase 1.0, not how to solve a particular case. Within the "HELP" directory are "QUESTION" and "ANSWERS" sub-directories. Help questions and their corresponding answers are stored here.

D.) Signs

Students can receive hints on the meanings of specific physical signs. The instructor places this information here. Much like the "DISEASES" directory, names and descriptions regarding specific signs are stored in their appropriate directories.

E.) Symptoms

See explanation for "SIGNS" directory.

File Naming Convention

Because of DOS's eight-character file name limitation, the naming of files that MediCase can read becomes an exercise in cryptography. This elaborate file naming convention is the key to running Medicase. The program utilizes these file names to select and present the proper information to the student. An explanation of the file naming convention used by MediCase, will use the following file name as an example: 1fhq3.txt. All files pertaining to a specific case will have names beginning with that case's number. Hence, this file belongs to Case #1. The "fh" says that this file contains information concerning the family history for Case #1. The "q" that follows tells us that it is a question. Finally, the last digit says that this is Question #3 in this case's family history. As another example: file 4igc2.txt belongs to Case #4. The "igc" tells us that this is the cost for an improper test that is graphical in nature. The "2" says that this file pertains to improper-graphics-test #2. With this understanding of the file naming convention, let's put in our first case.

Setting Up a Case

As previously mentioned, the files that are read by MediCase must be in the form of text or bitmap files. Any word processing program can be used to write questions, answers or any other data as long as it is saved in text format. Here are a few guidelines that you will need to follow so that MediCase can properly read your text files:

A. Text file hints

1.) Put all text in quotes - MediCase opens a text file and simply reads anything in double quotes. Even if you write War & Peace, there must be just one set of quotes. The student can access the entire entry by using the scroll bars in Windows¨.

1pia1.txt illness\answers Answer to "Present Illness" question #1
1fhq1.txt famhist\question "Family History" question #1
1fha1.txt famhist\answers Answer to "Family History" question #1
1phq1.txt pasthist\question "Pas History" question #1
1pha1.txt pasthist\answers Answer to "Past History" question #1
1obsr1.txt physical\observe\regions Name of region #1 observed in physical exam for Case #1
1obs1.txt physical\observe Description of region #1 observed in physical exam for Case #1
1ausr1.txt physical\auscult\regions Name of region #1 auscultated in physical exam for Case #1
1aus1.wav physical\auscult Sound file of region #1 auscultated in physical exam for Case #1
1palr1.txt physical\palpate\regions Name of region #1 palpated in physical exam for Case #1
1pall1.txt physical\palpate Description of region #1 palpated in physical exam for Case #1
1phgr1.txt physical\graphics\regions Name of picture of region #1 of the physical exam for Case #1
1plg1.bmp physical\graphics Bitmap of region #1 of the physical exam for Case #1
1pgc1.txt proper\graphics\costs Cost of proper test #1 (graphics form) for Case #1
1pgt1.txt proper\graphics\titles Title of proper test #1 (graphics form) for Case #1
1pg1.bmp proper\graphics Bitmap of proper test #1 for Case #1
1ptc1.txt proper\text\costs Cost of proper test #1 (text form) for Case #1
1ptt1.txt proper\text\titles Title of proper test #1 (text form) for Case #1
1pt1.txt proper\text Results (text form) of proper test #1 for Case #1
1igc1.txt improper\graphics\costs Cost of improper test #1 (graphics form) for Case #1
1igt1.txt improper\graphics\titles Title of improper test #1 (graphics form) for Case #1
1ig1.bmp improper\graphics Bitmap of improper test #1 for Case #1
1itc1.txt improper\text\costs Cost of improper test #1 (text form) for Case #1
1itt1.txt improper\text\titles Title of improper test #1 (text form) for Case #1
1it1.txt improper\text Results (text form) of improper test #1 for Case #1
disn1.txt diseases\names Name of disease #1
dis1.txt diseases Description of disease #1
signn1.txt signs\names Name of sign #1
sign1.txt signs Description of sign#1
sympn1.txt symptoms\names Name of symptom #1
symp1.txt symptoms Description of symptom #1
hlpq1.txt help\question Help question #1
hlpa1.txt help\answers Answer to help question #1
1dx.txt case1 Final Diagnosis for Case #1

Fig. 2 - MediCase File List

2.) Don't worry about margins, carriage returns, fonts, or justification. MediCase will format the text to fit within the appropriate text box. Also, you can store files in any order within their respective directories since they will be displayed in alphabetical order.

B. Graphic file hints

1.) Keep them small - When scanning in a picture, the end result should be no greater than 700K at 256-colors. Anything more than this probably won't be of any help. In the end, MediCase will fit the bitmaps in a predetermined window of fixed size. So if you've got a bitmap that requires a 21-inch monitor to be seen in full size, you've wasted your time and a lot of disk space.

2.) Keep them square - the window that your bitmap files will appear in is approximately square. The window has a "stretch" property that fits the bitmap in this frame. So if your picture is tall and thin, it will look short and fat in MediCase.

C. File lists

Follow the file list in Figure 2 to enter the necessary data for your first case. If you choose not to put data in for any one particular category, e.g. past history, that's acceptable. Nothing will show in the program. But if you enter five questions and four answers, this creates a problem. For every question there must be an answer. For every graphic there must be a title. For every test there must be a cost and title. This is necessary otherwise the program will 'crash'.

Running MediCase

Medicase is comprised of a Visual Basic¨ project file (.MAK file). It is necessary to have a version of Visual Basic¨ in order to run this file or program, however, an executable file (EXE file) can be generated by the authors after you have entered files into specific directory structures. After all of the required files for a case are entered, the program can be tested. The student is led sequentially through the process of diagnosis by allowing only certain menu items to be enabled at the proper phase of the process.

A) Opening a Case: Click on the "File Menu" to open a case. A small window will appear with a list of case titles. To open a case, just double-click on the appropriate title. You can only open one case at a time. Once you've opened a case, you are allowed to begin with a patient interview. Thus, the "Interview" button will be enabled. Click on it.

B) Interview - After clicking on the "Interview" button, two windows will appear. The main window contains buttons that will allow you to ask a variety of questions that have been created by the instructor. The other window is a picture of your patient. You can close any window at anytime by clicking on the upper, left corner control button.

C) Physical Exam - Up to a certain point in the interview process, the "Physical Exam" button will be enabled, allowing you to "perform" a physical. The data that you receive will be in the form of text, graphics (bitmaps), and sound (*.wav files).

D) Special Tests - While attempting to diagnose the patient, you may need to request special tests (EKG, echocardiogram, chest x-ray, etc.,.). The tests requested should be highly specific and appropriate to make the diagnosis. Do not perform a CAT Scan if you think you are dealing with a dermatological problem. Requesting inappropriate tests will cause your performance score to decrease.

E) Signs & Symptoms - These options are here to provide hints on certain signs and symptoms that are associated with the cases that have been entered. Since there is a slight scoring penalty for using this resource, this option should only be used when you are really unsure about the meaning of a particular sign or symptom.

F) Adjusting Your Screen - MediCase permits the user to choose between two different window sizes. The program was written for graphics resolutions of 1024 X 768 or 800 X 600. If you run Medicase at 640 X 480 resolution you can use the "Reduce" option which will make the windows smaller to fit the screen. Screen resolution is selected using the "Options Menu" and clicking on the only option available at this time, "Adjust Screen."

Summary

Medicase was designed to allow instructors to set up educational case presentations without the need for elaborate programming skills. The student is guided through the sequence of problem solving by the program. Motivational factors are provided to encourage the student to perform optimally. Typical clinical case histories can be developed to familiarize students with terminology and procedures. The subdirectory structure and file naming are critical in developing cases to run under Medicase. It is necessary to have Visual Basic ¨ in order to run the Medicase.Mak file, however, an executable program (.EXE file) can be generated if the file structure for a case is sent to the authors. Any comments or criticisms regarding this program can be directed to:

Joseph Boyle, MD or Kenneth Friedman Ph.D.
Department of Physiology
NJ Medical School
185 South Orange Ave
Newark, NJ 07103.

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