Editor's note:
This is an update from an article that first appeared in the March 2005 issue of
DVM Newsmagazine.
Most veterinarians would agree that a correct diagnosis is an essential prerequisite to consistently providing safe and effective
treatment for various illnesses. Diagnosing specific causes of disorders is of clinical importance since it facilitates accurate
forecasts (e.g., prognosis) of the biologic behavior of the disorder and selection of the type (e.g., specific, supportive,
symptomatic or palliative) of therapy for the disorder.
However, diagnoses are often a matter of opinion rather than a matter of fact. After all, isn't it true that most diagnoses
often require us to make decisions in the absence of certainty?
Rather, our diagnoses are based on probability. Since this is the case, we must be careful not to fall into the trap of making
diagnoses based on faulty logic or insufficient information. It's one thing to make a diagnosis and another to be able to
substantiate it. Although we name the things we know, we don't necessarily know them because we name them. This axiom certainly
applies to diagnoses.
Shortcuts in diagnostic reasoning tend to become increasingly prevalent when we veterinarians are subjected to the pressures
of a high caseload in a busy hospital. In this context, shortcuts often are defended based on practicality. Although practicality
is a virtue, we must not use the concept of practicality as an excuse for ignorance. Why? Because, taking shortcuts that result
in a misdiagnosis ultimately may be more detrimental to the patient than the illness. A wise sage once penned: "Heaven defend
me from a busy doctor."
Diagnostic pitfalls
Recall that the problem-oriented veterinary medical system is a conceptually straightforward, structured and reproducible
set of rules and directions that efficiently and effectively guide our care of patients. It's based on four related phases
of medical action:
1. Initially collecting information (i.e., database)
2. Identifying problems (i.e., problem list)
3. Devising plans to further refine the causes of problems and to treat the problems (i.e., initial plans)
4. Interpreting and recording additional information generated by initial plans to determine if additional diagnostic or therapeutic
plans are necessary (i.e., follow-up plans or progress notes).
A frequent error in diagnostic reasoning, even made by veterinarians with years of experience, is prematurely guessing the
specific cause of an illness without, first, verifying the presence of the problems (especially problems identified by owners);
second, localizing problems to various organs or body systems; or third, considering basic pathophysiologic disease mechanisms
that might be involved.
Bypassing the fundamental priorities of diagnostic planning often results in overdependence on past experiences or textbook
descriptions to identify the underlying causes of disease. As a result, our ability to recognize specific causes of diseases
that we have not previously encountered is hindered.
Likewise, memorizing textbook descriptions of characteristic clinical findings of specific diseases is not consistently effective.
Why? Because, in different patients, the same disease typically induces various manifestations of different degrees of severity.
Most textbook descriptions are compilations of prototypical disease manifestations, all of which don't coexist in the same
patient. Why is this generality important? Because, just as no two individuals are exactly alike in health, so are there no
two alike in disease.
TABLE 1 DAMN IT acronym of pathophysiologic causes of disease
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Based on the premise that a well-defined problem is half-solved, the primary objective here is to summarize application
of the "DAMN IT" acronym (Table 1) as an aid formulating diagnostic plans (a component of the third phase of medical action
of the problem-oriented system).
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