Clinical Reasoning & Differential Diagnosis

Question 1

DIsease

Answer 1

A disturbance of structure or function

Question 2

Asymptomatic Disease

Answer 2

HTN, disease is present but not symptomatic

Question 3

Subjective data

Answer 3

changes in the body perceived by the patient, Lab tests that were done at a previous visit

Question 4

Classification of Disease:Metabolic

Answer 4

Disturbances of cellular energy processes

Question 5

Classification of Disease: Neoplastic

Answer 5

Characterized by abnormal cell growth

Question 6

Disease Risk Factor Categories:Disease-associated

Answer 6

Past illnesses that increase risk

Question 7

Disease Risk Factor Categories: Treatment-associated

Answer 7

Surgical, transfusions, medications, allergies & adverse reactions, immunizations

Question 8

Natural History of Disease (A-F)

Answer 8

A)Biologic onset of the condition
B) Pathologic evidence of disease detectable by screening
C)Signs and Symptoms of disease
D)Health care sought
E) Diagnosis of Disease
F) Treatment of Disease

Question 9

Preclinical- natural history of disease

Answer 9

A) Biologic onset of the condition
B) Pathologic evidence of disease detectable by screening

They don’t know they have it-Screenings

Question 10

Clinical- natural history of disease

Answer 10

C)Signs and symptoms of disease
D) Health care sought
E) Diagnosis of Disease

Question 11

Outcome-natural history of disease

Answer 11

F) Treatment of disease

Question 12

Components of a patient problem

Answer 12

• Location
• Character or quality
• Severity
• Timing: onset, frequency, duration
• Sequence of symptoms
• Aggravating/ alleviating factors
• Associated factors and treatments

Question 13

Deductive Reasoning with example

Answer 13

from general to specific

example: “Im tired–> hypothyroid”

Question 14

Inductive Reasoning

Answer 14

from specific to general- uses probability theory

example: “Its probably this….lets order this test”

Question 15

Critical Decision-making steps

Answer 15

Synthesis of relevant info
Prediction of outcomes
Examination of assumptions
Generation of options
Identification of patterns
Choice of actions

Question 16

Differential Diagnosis

Answer 16

Consideration of possible causes that account for clinical manifestations

Question 17

What are differential diagnosis based on?

Answer 17

Clinical hx, social hx, family hx, physical exam

Question 18

Constructing a differential diagnosis 1-5

Answer 18

1. )Data acquisition
2. )Accurate problem representation
3. )Develop differential diagnosis
4. ) Prioritize the differential diagnosis
5. ) Test your hypotheses

Question 19

Differential Diagnosis steps 1) Data acquisition 2) Accurate problem representation

Answer 19

1) Identify most important cues (cause, timeline, label for cluster of symptoms)
2) Understand & preform advanced examination techniques (Risks)

Question 20

Differential Diagnosis step 3) Develop a complete framed differential diagnosis

Answer 20

Develop a list of possible causes (lists from textbooks, anatomic framework, organ/system framework)

Question 21

Differential Diagnosis step 4) Prioritize the deferential diagnosis

Answer 21

Prioritize the list: 
possible
 probabilistic
 prognostic 
pragmatic

Question 22

Possibilistic approach

Answer 22

all known causes treated as equally likely

Question 23

Probabilistic approach

Answer 23

consider those that are more likely first

Question 24

Prognostic approach

Answer 24

consider most serious first

Question 25

Pragmatic approach

Answer 25

consider diagnoses most responsive to treatment first

example: “lets try steroid cream then if that doesnt work we will try this”

Question 26

Steps in Diagnostic Reasoning

Answer 26

1) Identify the presenting problem
2) Assess patient
3) Formulate competing diagnoses
4) Order diagnostics
5) Select a diagnosis
6) Develop a treatment plan
7) Implement & evaluate the treatment plan:provide follow up care

Question 27

Electromyogram (EMG)

Answer 27

• Measures electrical activity of skeletal muscle during contraction and at rest
• Can identify inflammatory and degenerative diseases of skeletal muscles and abnormal nerve conduction

Question 28

CT scan

Answer 28

xray, visualizes soft tissue & organs with more detail

Question 29

MRI

Answer 29

produces images similar to CT but with high energy magnetic fields, no radiation, not useful for bones

Question 30

Positron Emisson Tomographic (PET) scan

Answer 30

looks at glucose uptake in body

Question 31

Sensitivity definition and calculation

Answer 31

Ability of the test to detect patients WITH disease who test positive for the disease

true positives / total number of positive results

Question 32

Specificity definition and calculation

Answer 32

Ability of the test to detect patients WITHOUT disease

true negatives/ total number of negative results

Question 33

Positive predictive value and calculation

Answer 33

probability that the person has the disease if the test result is positive

True positive test result /total positive test results

Question 34

Negative predictive value

Answer 34

Probability that the person does not have the disease if the test result is negative

Question 35

Bayes Theorem

Answer 35

Predictive values relate to characteristics of a test & the frequency of the disease in a population

Question 36

positive likelihood ratio definition and calculation

Answer 36

True positive% / False Positive %
=sensitivity /(1-specificity)
It tells you how likely it is that a result is a true positive rather than a false positive

Question 37

negative likelihood ratio definition and calculation

Answer 37

False Negative%/ True negative %
=(1-sensitivity) / specificity
It tells you how likely it is that a result is a false negative rather than a true negative

Question 38

LR >1

Answer 38

Test result is more likely to occur among patients with the disease than among those without the disease

Question 39

LR <1

Answer 39

Test result is less likely to occur among patients with the disease than among those without the disease

Question 40

LR >10

Answer 40

“rule in” disease

Question 41

LR<0.1

Answer 41

“rule out” disease

Question 42

Screening programs are most productive & efficient if directed at a low or high risk population?

Answer 42

high

Question 43

Key steps in test selection and interpretation

Answer 43

1) Careful H&P
2) development of differential Dx’s
3) Consideration of estimated probability of disease
4) Selection od best test for situation
5) Interpretation of results
6) Continue cycle or “watchful waiting”