Download case

A Guide To The oral Exam
Dr. IZZELDIN EL-JACK, M.D
Consultant Public Health
DHA
Oral Exam Setting
General advices










Face to face
Comfortable position
Be a good listener
Understand the question
Think before you speak
Organize what you say, short pause permissible
Good start is essential (1st impression is the last)
Say what you know, do not bluff or guess
Rationalize and defend your answer
Show good manners & do not argue with the
examiner
ICD
International Classification for Disease
Viral hepatitis A => ICD – 9070.1;ICD –10B15
Malaria => ICD – 9 084; ICD-10 B50-B54
Epidemiology
The study of distribution, determinants and disease
frequency in human population





Descriptive Epidemiology
Analytical Epidemiology
Distribution: time, place, person
Determinants of health: hereditary, environmental,
lifestyle, socio-economic, family and serviced welfare
services
Frequency: prevalence , incidence
Screening
Is the presumptive identification of
unrecognized disease or disability by
rapid application of tests, examination,
or other procedures
Screening criteria
- Disease
- Test
Reliability
- Repeatability
The ability of the test to provide consistent results
- Errors:
Observer error
1.
1.
2.
2.
3.
( intra-observer error): observer him self
( inter-observer error) : different observers
Instrumental error
Biological error: pt himself: not fasting, smoking
before doing BP check
Validity
The ability of the test to correctly identify
those individuals who actually have the
disease and those who do not
Sensitivity
The ability of the test to identify correctly
those who have the disease
Specificity
The ability of the test to identify correctly
those who do not have the disease
Validity
Positive Predictive Value
The likelihood that a person with a positive test has
the disease
Negative Predictive Value
The likelihood that a person with a negative test has
not got the disease
Likely hood ratio
+ = sensitivity / 1- specificity
_ = 1- sensitivity / specificity
Surveillance

The ongoing and systematic collection,
analysis, and interpretation of health data in
the process of describing and monitoring a
health event. The information is used for
planning, implementing and evaluating public
health interventions and programs.
Sources of disease surveillance data







Individual case reports
Laboratory reports
Accident & Emergency (A&E) records
Hospital discharges summaries
Case investigations revealing additional
cases
Death certificates
Surveys
Purposes of Surveillance
1.
2.
3.
4.
5.
Monitor disease trends so that planning can be
adjusted to meet new situations.
Identify,investigate and help control
outbreaks or epidemics.
Identify specific population groups at high risk of
illness or death from priority health events.
Evaluate the impact of preventive and
curative control activities on the incidence and
prevalence of priority diseases in the community.
Confirm current priorities among disease
control activities.
Health


It is the over-all Physical, Mental and Social
well-being of a person.
WHO definition
Is state of complete physical, mental, and social well
being and not merely the absence of disease.
in order to lead socially and economically
productive live.
Dimensions of health





From the definition (scope of health):
Physical
Mental
Social
Others
Determinants of health






‫االشياء المؤثرة على الصحة‬
Heredity : genetic : what we born with
Environmental: newborn: malaria bite
Life style: smoking, diet
Socio economic conditions
Health and family welfare services
Indicators of health
Tools to measure health
1. Mortality
2. Morbidity and disability
3. Nutritional
4. Environmental: municipality
5. Psycho-social
6. Health services
7. Utilization :of services
8. Health policies: budget provided by government

, and their interest in heath
Why indicators are important






Compare between countries
Plan for services
Plan for control and prevention
Indentify measures of health
problem
To allocate resources
Evaluation of the problem
Health care



Multitude of services rendered to
individuals, families or communities by
the agents of the health services for
the purpose of promoting, maintaining,
monitoring or restoring health.
Largely a government function.
Medical care is a subset of health care
Health care
Group of services provided to
individual, family, community by the
agent of health services (PHC,
community doctors, municipality..) for
the purpose of:
promoting, maintaining, monitoring or
restoring(those who have
disease)health.

Definitions
Disease (Morbidity): pathology
It is a departure from state of well-being to
unhealthy state…when one organ go unwell
The inability of the human body to meet internal or
external stresses with adequate reaction
Illness:
Subjective..sense of feeling unwell
Sickness:
Social dysfunction: he can’t come today
because he is sick, he took sick off
Disability
Any temporary or long term reduction of
an individual activity as a result of acute
or chronic condition ;CVA consider temporarily as
pt might recover after rehabilitation
Risk Factors
Factors favoring development of disease
often are present early in life outdating
the appearance of disease by many years
e.g.: person obese (risk factor) now, after 10
years will develop DM
Concept Of Disease



Disease = without ease (uneasiness-discomfort):
when something is wrong with the bodily
function.
Illness :
Individual’s perceptions and behavior in response
to the disease.
(a subjective state of the person who feels aware
of not being well)
Sickness refers to state of social
dysfunction.
Concept of Epidemic






Epidemic Vs outbreak
The occurrence of a number of cases of a disease (or
condition) in excess of a number expected in a given
time and place.
In some instances a single case will constitute such
an unusual occurrence
e.g UAE is free of malaria: 0 cases, so one case consider
epidemic
The cases are present in the country in certain percentage, but
when it exceed this percentage expected, so here we call it
epidemic
And to know if the number is exceed normal: we go back to
surveillance we did about this disease
-
-
Epidemic curve
1.Common source epidemic
- Point source:
e.g people invited to dinner, all ate same
food, all get food poison, all report to hospital at the same
time.
- Continuous source: one same source
like the story of water source in London.
OR shawarma cook has salmonella , every day he will transmit
the disease to some one, continuously from same source.
-
-
2.Propagated epidemic:
not same source
people got dystenry, they treated, but one of them partially
recovered, we to al ain, transmit the disease to other
group, this group treated, but one transmitted to other
group and so on.
Slow epidemic
Investigation of outbreak
Investigation of outbreak
1.
2.
3.
4.
5.
6.
Verification of diagnosis: confirm Dx
Confirm the existence of an out break: No. exceed expected
Defining the population at risk: case definition
Rapid search for all cases and their characteristics
Evaluation of ecological factors: cause of the problem
Formulation of hypothesis: dystentry from water source in
khawaneej
7.
Testing hypothesis: Data analysis: odds ratio, epidemic
curve
8.
9.
Control and prevention: action
Final report: recommendation
Steps by Ameera
1.
2.
3.
4.
5.
6.
7.
Confirm the Dx
Make sure it is an out break
Make case definition and search for the
cases
Put the hypothesis: the cause is ….
Test the hypothesis: collect the data and
analyze, odds ration, epidemic curve
Develop and implement control and
prevention
Report.
Endemic
Continuous presence of a disease or
infectious agent within a given
geographical area
e.g. TB in India
- Hyper-endemic

Expresses a persistence intense Transmission
- Holo-endemic

A high level of infection beginning early in life which affect
most population.
Control Vs Eradication
Control:
It is reduction of the disease transmission to
an acceptable minimum, or to a level not be
considered a major public health problem
Eradication:
Complete elimination of a disease, or
complete cessation of transmission and
infectious agent
Communicable disease
every communicable d. is infectious
A disease capable of being transmitted from an
infected person or species to a susceptible host,
either directly or indirectly.
Carrier
carry disease without symptoms : HIV
A person or animal that harbors a specific infectious
agent in the absence of clinical disease and serve as
a potential source of infection.
Contact
A person or animal that has associated with an
infected person or animal that might provide an
opportunity to acquire the infection.
Infectious disease: disease caused by infectious agent
Disinfection
Killing of infectious agents outside the body by direct
exposure to chemical or physical agents.
High level disinfections refers to the inactivation of all
microorganisms except some bacterial spores.
e.g. what we do at home: cleaning
Concurrent disinfection
Immediate disinfections and disposal of discharges
and infective matter all through the course of a
disease.
Concept of communicability

Infectivity:
Ability of the infective agent to enter,
survive, and multiply in the host
He has the disease but not showing S&S

Pathogenicity:
cause destruction of organs
The property of an organism that determines
the extent to which overt disease is
produced in an infected population i.e the
power of an organism to cause disease

Virulence:
The degree of pathogenicity, it is the
disease-evoking power of the organism in a
given host
Measures of Morbidity
1. Incidence:
new cases, need immediate action,
it measure risk
2. Prevalence :
existing cases: new & old: used
to plan for future, measure magnitude of disease
3. Attack rate:
for primary cases
• Index case: first person report health services
(went to hospital)
• Primary cases: people who first exposed
directly to the source of infection
4. Secondary attack rate
• Secondary cases :who got the disease but
didn’t expose to the source of infection, bur
from the primary cases
• Why we calculate the 2ndy Attack rate:

To know the infectivity(communicabilty) of the
disease .i.e. if it is infectious or not.
Measures of Mortality
1.
Crude death rates :
2.
Specific death rates
3.
Standardized rates
4.
Case fatality rates ‫ اكثر فتكا‬:
5.
all death in dubai, it is not
accurate , can’t be used for comparison, to make it better
we have standardized it
Proportionate mortality ratio : ‫اكثر تسببا‬
‫ في الوفاة‬e.g.We have 10 diseases causes death, breast
cancer PMR is the highest
6.
Fetal and maternal mortality rate
Disaster


An event that overwhelmed the
affected community and that really
requires outside assistance.
Emergency: same but require inside
assistance only
What’s the Design?
Define treatment and control groups.
Administer exposure to treatment group, but not controls.
Follow through time and compare rate of disease in
treatment group with rate of disease in control group.
Epidemiologist is involved during the entire time from
exposure and disease.
Randomized Trial
What’s the Design?
Select a healthy study sample.
Observe who is exposed and who is not exposed.
Follow through time and compare rate of disease in
exposed group to rate of disease in unexposed group.
Epidemiologist is involved during the entire time from
exposure and disease.
Cohort Study
What’s the Design?
Select a group of people with disease and a similar group
of people without the disease.
Ask both groups about their exposures in the past.
Compare proportion of exposure in diseased group to
proportion of exposure in non-diseased group.
Epidemiologist is involved after disease has occurred
and relies on subjects’ memories to gather information
about exposure.
Case-Control Study
What’s the Design?
Select a study sample.
Ask each person about both exposure and disease at that
point in time.
Disease rate in exposed group is compared to disease rate
in unexposed group.
Epidemiologist gathers data only at that one point in time.
Cross-Sectional Study