Most would agree that a correct diagnosis is an essential prerequisite to providing safe and effective treatment for various
Diagnosis of specific causes of various clinical disorders is of importance because it facilitates: 1) accurate forecasts
(e.g. prognosis) of the biological behavior of the disorder, and, 2) selection of specific (rather than symptomatic or supportive)
therapy for the disorder. However, diagnoses are often a matter of opinion rather than matter of fact. In fact, isn't it true
that most diagnoses often require us to make decisions in the absence of certainty?
Our diagnoses are based on probability. This being the case, we must use caution not to fall into the trap of making diagnoses
on the basis of faulty logic or insufficient information. It is one thing to make a diagnosis and another to be able to substantiate
it. Though we name the things we know, we do not necessarily know them because we name them.
Shortcuts in diagnostic reasoning tend to become increasingly prevalent when veterinarians are subjected to the pressures
of a high caseload in a busy hospital.
In this context, short cuts are often defended on the basis of "practicality". Although practicality is a virtue, we must
use caution not to use the concept of practicality as an excuse for ignorance. A misdiagnosis can be more detrimental to the
patient than the illness. A wise sage penned this thought: "Heaven defend me from a busy doctor."
Recall that the problem-oriented veterinary medical system is a simple, structured and reproducible set rules and directions
that efficiently and effectively guide our care of patients. It is based on four related phases of medical action: 1) initial
collection of information (so-called database); 2) identification of problems (so-called problem list; 3) devising plans
to further refine the causes of problems, and also devising plans to treat the problems (so-called initial plans); and, 4)
interpretation and recording of additional information generated by initial plans in order to determine whether additional
diagnostic and/or therapeutic plans are necessary (so-called follow-up plans; also called progress notes).
A frequent error in diagnostic reasoning, made even by veterinarians with years of experience, is prematurely guessing the
specific cause of an illness, first, without 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. Making a practice of bypassing the fundamental priorities of diagnostic planning often results in
over dependence on past experiences or textbook descriptions to identify the underlying causes of various diseases. As a result,
our ability to recognize specific causes of diseases that we have not encountered previously is hindered. Likewise, memorization
of textbook descriptions of characteristic clinical findings of specific diseases is not consistently effective. Why not?
In different patients, the same disease typically induces a variety of manifestations of different degrees of severity. Most
textbook descriptions are compilations of prototypical manifestations of diseases, all of which do not coexist in the same
patient. Just as no two individuals are exactly alike in health, so neither are any two alike in disease.