Case Unit 1: Cholera Flashcards
What is a case report?
First line of evidence Detailed story of a unique or unexplained case Presentation of new information Observational Lowest level evidence
Advantages of a case report
Good way to detail new cases
Useful for identifying new diseases or new drug side effects
Can be used to generate research hypotheses
Disadvantages of a case report
May focus too strongly on misleading/unimportant aspects
The features of this specific case may not be applicable to others with the disease
What is a case-control study?
Identify a group of people with the disease and match them to a group of people without the disease
Look back (retrospectively) to try and identify exposure to risk factors in the case group
Observational
Advantages of a case-control study?
The disease has already occurred so no waiting around
Good for studying rare diseases as all the known cases can be included
Multiple risk factors can be examined at once
Disadvantages of a case-control study?
May be difficult to find a closely matched control group for the case group
Relies on accurate memory, there may be recall bias
What is a cohort study?
One (or more) cohorts are followed (prospectively) and ‘measured’ at intervals to track disease development/if they are developing it at all
Different cohorts may have one varying risk factor between them, but are matched otherwise to eliminate confounding variables
Advantages of a cohort study
Not as expensive as the conditions are ‘natural’ i.e. not controlled like in a randomised-control trial
Disadvantages of a cohort study
May take a long time for the disease of interest to develop
People may decide to drop out
The cohorts are not randomised so there may be other unidentified confounding variables influecing the different outcomes of the cohorts
What is a randomised control trial?
Participants randomised into control group and intervention group
Intervention group given treatment
Dependent variable measured from both groups
Statistical analysis used to determine difference between groups
Advantages of randomised control trial
Groups are randomised to eliminate confounding variables and population bias
Can be placebo-controlled
The researchers and participants can be blinded
Disadvantages of randomised control trial
May be bias in the type of people who volunteer to participate
Expensive to run and time-consuming
What are Koch’s Postulates?
The disease-causing organism must be present in those with the disease and not in those without it
The organism should be isolated from a diseased person and grown in pure culture
The cultured organism should be inserted into a healthy person and cause disease to develop
The organism should be re-isolated and shown to be identical to the original organism
What is a paradigm shift?
A shift in the way society views a certain topic in terms of approach and assumptions
What are the steps of a paradigm shift?
New evidence is presented that contradicts the current theory
Current theory undergoes crisis
New paradigm is established
