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Diagnosis overview


The “art” of diagnosis is largely the ability to rank probabilities based on the incidences of likely diseases, and the chance of encountering given clinical features within each disease. The Diagnosis module allows you to indicate clinical findings and use these findings to generate a ranked diagnosis list GIDEON’s database. The Diagnosis tab includes the following sections:

Clinical Presentation

Clinical Presentation Lists Country, Incubation period and Signs and Symptoms by specific categories. An information box defines all technical terms when mousing over the signs and symptoms.

Country of disease acquisition

Choose the country in which the patient acquired the disease. Country selection
Generally the list of country names corresponds to accepted geographical and political designations. Certain territories, protectorates, etc are listed separately when their infectious disease status differs significantly from that of the ‘mother’ country. Thus Puerto Rico and Guam are processed as autonomous epidemiological entities by GIDEON. In contrast, newer countries or semi-autonomous regions (ie, East Timor, Scotland) will continue to appear in the app as part of the mother-nation (ie, Indonesia, United Kingdom).
The default < Worldwide > option is useful when generating a comprehensive list of all diseases associated with specific clinical findings.

Country Synonyms

Many countries are known by alternate names, which may not appear on the general country list; ie, Burma vs. Myanmar. Click [S] to display a country synonym list and search by alternative name, regional name (e.g. Corsica vs. France) or older name (e.g. French Somaliland vs Djibouti).

Bioterrorism Simulator

The Bioterrorism simulator is designed for diagnosis and informatics relevant to the military and paramilitary use of human Infectious Disease agents. You will note that ‘< Bioterrorism simulator >’ is listed as a ‘Country’ in both the Diagnosis and Diseases modules. When clinical signs and symptoms are entered in the Diagnosis module, the resulting differential diagnosis list includes only diseases considered as potential agents of bioterrorism. Note that this list is not Bayesian; ie, all relevant diseases are assigned an equal ‘incidence’ when calculating probability.

Incubation Period

Dates can be typed manually into the box, or by clicking on Calendar icon. Three parameters display the time frame from dates of exposure, until the onset of disease. Exposure may represent foreign travel, animal exposure, ingestion of a suspected food, sexual contact, etc.
Incubation period
Disease Onset: Enter the date the disease first appeared.
Exposure began: Enter the date exposure began. The number of days from the first date of exposure until the onset of the disease is displayed to the right.
Exposure ended: Enter the date exposure ended. The number of days from the last date of exposure until the onset of the disease is displayed to the right.

Signs and symptoms selection

Choose all clear-cut signs, symptoms and laboratory test results that you feel are related to the disease in question. The diagnostic specificity of this app increases with each additional entry. The absence of a certain finding is often as helpful as its presence.

checkmark (left click) displays a positive indication.
red X (right click) displays a negative indication.
appears when a given sign or symptom is incompatible with another that was previously marked.

When you click on the [+] which appears to the left of several signs and symptoms, a list of clickable sub-categories appears. For example, the heading “Dermatological – Skin and Soft Tissue” is followed by a listing of possible skin lesions.

In some cases, you may wish to generate a list of all diseases associated with a single finding or small group of findings (e.g., all of the diseases characterized by splenomegaly and eosinophilia). Such lists are often useful as teaching tools, but have limited value in diagnosing a specific patient.

Note: A built in safety mechanism ( fills the check box) prevents the entry of mutually-exclusive parameters (e.g., both vaginitis and orchitis) for the same patient. In some cases, seemingly contradictory findings (e.g., both neutropenia and neutrophilia) are permitted, since they may appear at different times during a given disease episode.


Suggestions Lists signs and symptoms which are most likely to shorten the differential diagnosis list, based on symptoms you’ve selected from the Clinical Presentation list.

Clinical Summary

Clinical summary Lists symptoms chosen in the Symptoms and Signs List.
red X Removes a selected symptom from the Clinical Summary list.

Diagnosis Results

Searches the database and constructs a diagnosis based upon the selected symptoms, signs, incubation period and country of acquisition. See Diagnosis Results.

Additional information