Medical problem solving part 3

Probability

the liklihood that the disease is present or absent

Prevelance

how often it happens in a total population

Pre test probability

the liklihood of a given disease before a diagnosic test result is known

Post test probability

liklihood of a given disease after test results are known

True positive

a positive test result for someone with the disease

True negative

the patient does not have the disease and the test is negative

False positive

positive test result in a patient without the condition

False negative

negative test result in a patient with the condition

Sensitivity

likelihood a test will be positiev in a pateint with the disease

Specificity

liklihood a test is negative in a patient without the disease

Likelihood ratios

tell a clinican how much the pre test probability will shift after the test results are known

Predictive values

designed to estimate the likeligood that a disease is present or absent in the person being tested

Positive predictive value

the likelihood that a disease is presnet given that a diagnostic test is positive, the more specific the better

Negative predictive value

the likelihood that a disease is absent given that a diagnostic test result is negative, the more sensitive the better

Types of diagnostic tests

laboratory tests, imaging, biopsies, blood tests, specimine tests

Why do we test

1. Establish a diagnosis

2. pateint management

3. Screening purposes

Gold standard

The best test that is known to diagnose

Action threshold

probabiity of a disease at the point which two choices have equivaent value

Testing threshold

benchmark for the use of diagnostic tests

Intra-rater reliability

The degree of agreement among multiple repetitions of a diagnostic test performed by the same person

inter-rater reliability

the degree of agreement amoung multiple people performingthe same test

Test-retest reliability

the degree to which the test will show the same result if repeated

Accuracy

the ability to test what it is supposed to measure

Precision

tests ability to reproduce the same result when repeated on the same sample

Sources of variability

- subjects

- instrumentations

- observer

Morbidity

adverse effects

Mortality

death

pitfalls to avoid

Ignoring a negative test and treating anyway, ignoring a positive test and not treating

Efficacy

the ability to produce a desired or intended result

Low therapeutic threshold

higher benefit, low risk

High therapeutic threshold

only treat if probability of disease is high, high risk

Cure disease

treatment meant to reverse disease causes or halt disease

Control disease

treatment used to prevent the porgression of disease

Reduce symptoms of disease

alleviate suffering from disease, pain management

Why might we not treat

No effective treatenent available, minimal impact, patient declines, end of life care

Harm

the adverse consequences of a treatment that would occur in a patient without the disease

Improvement

how much better the person with disease does with treatment compare to what their condition would be without treatement

benefit

how much better the patient with disease does with their tretemnt compare to what tier condition would be without

Treatment factors

Tretament of choice, efficacy of treatment, improvement to life, risks, cost

Types of treatment

lifestyle modification, pharmacotherapy, surgical treatment, rehab, alternative medicine

Evaluation phase

follow up to determine the effectiveness of the intervention

Disease prevention

actions aimed at minimizing the impact of the disease

primary prevention

prevent initial onset of condition, ex immunizations

Secondary revention

early detection of disease, halt or delay progression, ex cancer screenings

tertiary prevention

Optimize patients health once the disease is known, soften the impact of long term disease