Differential diagnosis

From Wikipedia, the free encyclopedia

In medicine, differential diagnosis (sometimes abbreviated DDx, ddx, or ΔΔ) is the systematic method healthcare providers use to identify the disease causing a patient's symptoms. In other words, part of diagnosis is attempting to narrow down the list of possible diagnoses until one emerges as the best. The term differential evolves from the word differences. The concept of differential diagnosis involves observing and discovering signs and symptoms, then progressively considering the most likely illnesses, then continuously narrowing down the possible diagnoses, eliminating one after another, until one is left with only one specific diagnosis for the patient's signs and symptoms.

Differential Diagnosis is the process whereby a given condition or circumstance, called the presenting problem or chief complaint, is examined in terms of underlying causal factors and concurrent phenomena as discerned by appropriate disciplinary perspectives and according to several theoretical paradigms or frames of reference, and compared to known categories of pathology or exceptionality. Differential diagnosis allows the physician to:

more clearly understand the condition or circumstance
assess reasonable prognosis
plan treatment or intervention for the condition or circumstance
enable the patient and the family to integrate the condition or circumstance into their lives, until the condition or circumstance may be ameliorated, if possible.

If the patient's condition does not improve, the diagnosis must be reassessed. The method of differential diagnosis was first suggested for use in the diagnosis of mental disorders by Emil Kraepelin. It is more systematic than the old-fashioned method of diagnosis by gestalt (impression).^{[citation needed]}

The method of differential diagnosis is based on the idea that you begin by first considering the statistically more probable diagnoses. Medical students are taught the adage, "When you hear hoof beats, think horses, not zebras." It means that only after more probable diagnoses are ruled out do the somewhat less likely ones considered, and so forth. It used to be that doctors ordered only particular blood tests, but now the standard is a full blood chemistry profile which can speed up the process of diagnosis as well as uncover sub-clinical conditions. With the advent of better radiological studies like MRI and the wider use of nuclear medicine, it has become more likely that there will be unexpected findings that will be further studied, despite the fact that the findings will not be supported by further investigation. They are a valuable tool, but not infallible. It still often takes a physicians or medical team to track down either a more common illness with a rare presentation or a rare illness with symptoms suggestive of many other conditions. Sometimes a definitive diagnosis might take years.

The term differential diagnosis also refers simply to a list of the most common causes of a given symptom, or a list of disorders similar to a given disorder.

The term differential diagnosis also refers to such lists when they are annotated with advice on how to narrow down the list (the book French's differential diagnosis is an example).^{[citation needed]} Thus, a differential diagnosis in this sense is medical information specially organized to aid in diagnosis.

The professional Merck Manual of medical diagnosis has 11 index entries describing the topic as differential diagnosis. The topic is mentioned within the body of 125 other separate articles on various medical conditions. reference below

1 Machine differential diagnosis
2 Use in popular culture
3 See also
4 Notes
5 References

[edit] Machine differential diagnosis

Machine differential diagnosis is the use of computer software to partly or fully make a differential diagnosis. It may be regarded as an application of artificial intelligence.

Typing in symptoms and signs in web search engines such as Google is one way of making a machine differential diagnosis.^{[citation needed]} This, however, still requires medical skills to compare multiple results. A more specific search engine is eMedicine, in which the entries are in addition graded on importance.

More advanced tools of differential diagnosis, e.g. DiagnosisPro, are commercial softwares.

However, these tools all still require advanced medical skills, in order to rate the symptoms and choose additional tests to deduce the probabilities of different diagnoses. Thus, non-professionals still need to see a health care provider in order to get a proper diagnosis.

Comparison
Tool	External link	Free	Requires medical skills
Google	[1]	yes	yes
eMedicine	[2]	yes	yes
DiagnosisPro	[3]	yes	yes
Dynamic Differential Diagnosis	[4]	yes	yes

[edit] Use in popular culture

The television show House, M.D. focuses on a team of diagnosticians that use differential diagnosis to identify patients' varied afflictions.

[edit] See also

[edit] Notes

[edit] References

"differential diagnosis." Merriam-Webster's Medical Dictionary. Merriam-Webster, Inc. 12 Aug. 2007. Dictionary.com.
"differential diagnosis." The American Heritage Stedman's Medical Dictionary. Houghton Mifflin Company. 12 Aug. 2007. Dictionary.com.