DDx Flashcards
DDx
Differential diagnosis is a systematic process used to identify the proper diagnosis from a set of possible competing diagnoses.
A differential diagnosis is a list of possible conditions or diseases that could be causing the patient’s symptoms. It’s based off of the facts obtained from the patient’s symptoms, medical history, basic laboratory results, and a physical examination.
It is a method of analysis of the patient’s history and physical exam to arrive at the correct diagnosis.
DDx is a process of weighing the probability of one disease vs. that of other diseases causing a patient’s illness.
learning how to identify a medical dx
As part of this process, review items such as:
Your patient’s current symptoms
Health history
Results from a physical examination
confirming a dx
The PCP will make a list of the most likely conditions or diseases that may be causing your symptoms. This is the differential diagnosis.
Prioritize your list differential diagnoses
It enables you to rule out possibilities and confirm a final diagnosis.
Critical thinking
Process by which the information is gleaned from the history and physical examination:
Merged with clinical knowledge, experience, and the current best evidence
Formulate the next steps in patient care -Development of the diagnostic and management plans
Critical reflection = Clinical reasoning
Critical reflection involves thinking through the reasoning for these decisions
The clinical examination
Thus far, we have been concerned with the initial interaction with the patient:
Establishment of respectful rapport
Information gathering processes -History and physical examination
Next steps:
Organizing
Integrating
Analyzing inform
Assessment, judgement, and evidence
Bringing the decision making, clinical experience, and knowledge of the patient together with the current best evidence regarding the issues involved
Assess information.
Assign priorities.
Form clinical opinion.
Reflect on own biases.
Integrate patient and professional preferences.
Assess further
Problem identification
Problem is anything that will need further evaluation and/or attention.
May be related to:
-Uncertain diagnosis
-New findings related to a previous diagnosis
-New findings of unknown etiology
-Unusual findings revealed in the clinical examination/laboratory tests
-Personal, social, or emotional difficulties
Formulate problems as specifically as possible.
The problem list is key to developing a complete understanding of a patient’s concern
Review the list and note the absence of findings that you might expect in support of your hypotheses. -Beware of “red herrings,” the bits of information that are distracting and draw your thinking away from central issues.
Critically evaluate unexpected or unusual findings, but do not let them distort full consideration of all you have learned
After a match between the data (both subjective and objective) and a presumed diagnosis is made -Consider the appropriate laboratory or radiologic studies to confirm the diagnosis.
-Specialty consultation may be needed before laboratory or radiologic testing and establishing the diagnosis. -Helps focus your investigation
Valid Hypotheses
Clinical reasoning allows you to consider and discard a variety of possible diagnoses—from the common to the rare.
There are at least three diagnoses for every disease (Kopp, 1997):
-The one that unifies what you have learned
-The one you cannot afford to miss
-The one that it actually is
Do not have tunnel vision or jump to conclusions during the interview.
Occam’s razor or lex parsimoniae (“law of parsimony” or “law of succinctness”)
-All findings should be unified into one diagnosis.
-This is not always true.
-More than one disease process can exist at one time in the same person.
Possible Barriers to Clinical Reasoning
Feelings, attitudes, and values can impair decision making.
Know yourself and take time for personal reflection.
Critical reflection involves thinking through the reasoning for these decisions.
The Ethical Context
Ethics does not provide answers.
Consideration of ethical principles provides the framework for respectful, flexible discussion and a disciplined approach to decision making.
For a given problem, consider:
-Autonomy
-Beneficence
-Nonmaleficence
-Utilitarianism
-Fairness and justice
-Deontologic imperatives
Mechanism and Probabilism
Mechanistic (deterministic) thinking is governed by a sense that knowledge must be certain and not subject to attributes of the observer.
Our decision making must have a balance between mechanism and probabilism (certainty in knowledge is impossible).
Do not be dominated by the mechanistic assumption that there is a precise and discoverable cause for every event.
Validity of the Clinical Examination
Great majority of diagnoses can be achieved with the information from a competent history and clinical examination.
Limit the indiscriminate use of expensive technology.
Keep in mind:
-Sensitivity
-Specificity
-True positive and true negative
-False positive and false negative
-Positive predictive value and negative predictive value
Bayes Theorem
Likelihood of your diagnosis being related to your findings depends on:
-Probability of those findings being associated with that diagnosis
-Prevalence of both that particular diagnosis and that combination of findings in the community in which you are serving
Evidence-Based Practice
Evidence-based practice (EBP) is a system that incorporates the best available scientific evidence into clinical decision making, in the care of the individual patient.
EBP balances the strength of the evidence, the risks and benefits of treatment (including lack of treatment), and diagnostic tests, while integrating clinical expertise.
Evaluation and Management Plan
You decide what you think is going on (the diagnosis) and what you are going to do about it (the management plan).
You and your patient arrive at a jointly considered approach involving:
-Laboratory and imaging studies
-Subspecialty consultation
-Medications, equipment, assistive technology
-Special care
-Diet and activity modification
-Follow-up visit
-Patient education
