A Guide To The oral Exam Dr. IZZELDIN EL-JACK, M.D Consultant Public Health DHA DHA.

A Guide To The oral ExamA Guide To The oral Exam

Dr. IZZELDIN EL-JACK, M.D Consultant Dr. IZZELDIN EL-JACK, M.D Consultant Public Health Public Health

DHADHA

Oral Exam SettingOral Exam Setting

General advicesGeneral advices

Face to faceFace to face Comfortable positionComfortable position Be a good listenerBe a good listener Understand the question Understand the question Think before you speakThink before you speak Organize what you say, short pause permissibleOrganize what you say, short pause permissible Good start is essential (1Good start is essential (1stst impression is the last) impression is the last) Say what you know, do not bluff or guessSay what you know, do not bluff or guess Rationalize and defend your answerRationalize and defend your answer Show good manners & do not argue with the Show good manners & do not argue with the

examinerexaminer

ICDICD

International Classification for DiseaseInternational Classification for Disease

Viral hepatitis AViral hepatitis A => => ICD – 9070.1;ICD –10B15ICD – 9070.1;ICD –10B15

MalariaMalaria => => ICD – 9 084; ICD-10 B50-B54ICD – 9 084; ICD-10 B50-B54

EpidemiologyEpidemiology

The study The study of distributionof distribution, , determinantsdeterminants and and disease disease frequencyfrequency in human population in human population

Descriptive EpidemiologyDescriptive Epidemiology Analytical EpidemiologyAnalytical Epidemiology

Distribution: time, place, personDistribution: time, place, person Determinants of health: hereditary, environmental, Determinants of health: hereditary, environmental,

lifestyle, socio-economic, family and serviced welfare lifestyle, socio-economic, family and serviced welfare servicesservices

Frequency: prevalence , incidenceFrequency: prevalence , incidence

ScreeningScreening

Is the presumptive identification of Is the presumptive identification of unrecognized disease or disability by unrecognized disease or disability by rapid application of tests, examination, rapid application of tests, examination, or other proceduresor other procedures

Screening criteriaScreening criteria- DiseaseDisease- TestTest

Reliability Reliability

- - RepeatabilityRepeatabilityThe ability of the test to provide consistent resultsThe ability of the test to provide consistent results

- Errors: - Errors:

1.1. Observer error Observer error 1.1. ( intra-observer error): observer him self( intra-observer error): observer him self

2.2. ( inter-observer error) : different observers( inter-observer error) : different observers

2.2. Instrumental errorInstrumental error

3.3. Biological error: pt himself: not fasting, smoking Biological error: pt himself: not fasting, smoking before doing BP checkbefore doing BP check

ValidityValidity The ability of the test to correctly identify The ability of the test to correctly identify

those individuals who actually have the those individuals who actually have the disease and those who do notdisease and those who do not

Sensitivity Sensitivity The ability of the test to identify correctly The ability of the test to identify correctly

those who have the diseasethose who have the disease

SpecificitySpecificity The ability of the test to identify correctly The ability of the test to identify correctly

those who do not have the diseasethose who do not have the disease

ValidityValidity

Positive Predictive ValuePositive Predictive Value The likelihood that a person with a positive test has The likelihood that a person with a positive test has

the diseasethe disease

Negative Predictive ValueNegative Predictive Value The likelihood that a person with a negative test has The likelihood that a person with a negative test has

not got the diseasenot got the disease

Likely hood ratioLikely hood ratio

+ = sensitivity / 1- specificity+ = sensitivity / 1- specificity

_ = 1- sensitivity / specificity_ = 1- sensitivity / specificity

SurveillanceSurveillance

The ongoing and systematic collection, The ongoing and systematic collection, analysis, and interpretation of health data in analysis, and interpretation of health data in the process of describing and monitoring a the process of describing and monitoring a health event. The information is used for health event. The information is used for planning, implementing and evaluating public planning, implementing and evaluating public health interventions and programs.health interventions and programs.

Sources of disease surveillance dataSources of disease surveillance data

Individual case reportsIndividual case reports Laboratory reportsLaboratory reports Accident & Emergency (A&E) recordsAccident & Emergency (A&E) records Hospital discharges summariesHospital discharges summaries Case investigations revealing additional Case investigations revealing additional

casescases Death certificatesDeath certificates SurveysSurveys

Purposes of SurveillancePurposes of Surveillance

1.1. Monitor disease trends so that planning can be Monitor disease trends so that planning can be adjusted to meet new situations.adjusted to meet new situations.

2.2. Identify,investigate and help control Identify,investigate and help control outbreaks or epidemics.outbreaks or epidemics.

3.3. Identify specific population groups at high risk of Identify specific population groups at high risk of illness or death from priority health events.illness or death from priority health events.

4.4. Evaluate the impact of preventive and Evaluate the impact of preventive and curative control activities on the incidence and curative control activities on the incidence and prevalence of priority diseases in the community.prevalence of priority diseases in the community.

5.5. Confirm current priorities among disease Confirm current priorities among disease control activities.control activities.

HealthHealth

It is the over-all It is the over-all PhysicalPhysical, , MentalMental and and SocialSocial well-being of a person.well-being of a person.

WHO definitionWHO definition

Is state of complete physical, mental, and social well Is state of complete physical, mental, and social well being and not merely the absence of disease.being and not merely the absence of disease.

in orderin order to lead socially and economically to lead socially and economically productive live.productive live.

Dimensions of healthDimensions of health

From the definition (scope of health)From the definition (scope of health):: Physical Physical MentalMental SocialSocial Others Others

Determinants of healthDeterminants of health

الصحة على المؤثرة الصحة االشياء على المؤثرة االشياء HeredityHeredity: : genetic : what we born withgenetic : what we born with EnvironmentalEnvironmental: : newborn: malaria bitenewborn: malaria bite Life styleLife style: : smoking, diet smoking, diet Socio economic conditions Socio economic conditions Health and family welfare servicesHealth and family welfare services

Indicators of healthIndicators of health

Tools to measure healthTools to measure health1.1. MortalityMortality2.2. Morbidity and disabilityMorbidity and disability3.3. NutritionalNutritional4.4. Environmental: Environmental: municipalitymunicipality5.5. Psycho-socialPsycho-social6.6. Health servicesHealth services7.7. Utilization :Utilization :of servicesof services8.8. Health policies: Health policies: budget provided by government , budget provided by government ,

and their interest in heathand their interest in heath

Why indicators are importantWhy indicators are important

Compare between countriesCompare between countries Plan for servicesPlan for services Plan for control and preventionPlan for control and prevention Indentify measures of health problemIndentify measures of health problem To allocate resourcesTo allocate resources EvaluationEvaluation of the problem of the problem

Health careHealth care

Multitude of services rendered to Multitude of services rendered to individuals, families or communities by individuals, families or communities by the agents of the health services for the agents of the health services for the purpose of the purpose of promoting, maintaining, promoting, maintaining, monitoring or restoringmonitoring or restoring health. health.

Largely a government function.Largely a government function. Medical care is a subset of health careMedical care is a subset of health care

Health careHealth care

Group of services Group of services provided to provided to individual, family, community by the individual, family, community by the agent of health services agent of health services (PHC, (PHC, community doctors, municipality..community doctors, municipality..)) for for the purpose of: the purpose of:

promoting, maintaining, monitoring or promoting, maintaining, monitoring or restoringrestoring(those who have (those who have disease)disease)health.health.

Definitions Definitions

Disease (Morbidity): pathologyDisease (Morbidity): pathology It is a departure from state of well-being to unhealthy It is a departure from state of well-being to unhealthy

state…state…when one organ go unwellwhen one organ go unwell

The inability of the human body to meet internal or The inability of the human body to meet internal or external stresses with adequate reactionexternal stresses with adequate reaction

Illness:Illness:Subjective..sense of feeling unwellSickness:Social dysfunction: he can’t come today

because he is sick, he took sick off

DisabilityDisability Any temporary or long term reduction of Any temporary or long term reduction of

an individual activity as a result of acute an individual activity as a result of acute or chronic condition ;or chronic condition ;CVA consider temporarily as CVA consider temporarily as pt might recover after rehabilitationpt might recover after rehabilitation

Risk FactorsRisk Factors Factors favoring development of disease Factors favoring development of disease

often are often are present early in life present early in life outdating outdating the appearance of disease by many yearsthe appearance of disease by many yearse.g.: person obese (risk factor) now, after 10 e.g.: person obese (risk factor) now, after 10 years will develop DMyears will develop DM

Concept Of DiseaseConcept Of Disease DiseaseDisease = without ease (uneasiness-discomfort): = without ease (uneasiness-discomfort): when something is wrong with the bodily function. when something is wrong with the bodily function.

IllnessIllness : : Individual’s perceptions and behavior in response Individual’s perceptions and behavior in response

to the disease.to the disease. (a subjective state of the person who feels aware (a subjective state of the person who feels aware

of not being well)of not being well)

SicknessSickness refers to state of social refers to state of social dysfunction.dysfunction.

Concept of EpidemicConcept of Epidemic

Epidemic Vs outbreak Epidemic Vs outbreak

The occurrence of a number of cases of a disease (or The occurrence of a number of cases of a disease (or

condition) in excess of a number expected in a given condition) in excess of a number expected in a given time and place. time and place.

In some instances a single case will constitute such In some instances a single case will constitute such an unusualan unusual occurrenceoccurrence

e.g UAE is free of malaria: 0 cases, so one case consider e.g UAE is free of malaria: 0 cases, so one case consider epidemicepidemic

The cases are present in the country in certain percentage, but The cases are present in the country in certain percentage, but when it exceed this percentage expected, so here we call it when it exceed this percentage expected, so here we call it epidemic epidemic

And to know if the number is exceed normal: we go back to And to know if the number is exceed normal: we go back to surveillance we did about this diseasesurveillance we did about this disease

- Epidemic curveEpidemic curve- 1.Common source epidemic1.Common source epidemic

- Point sourcePoint source: : e.g people invited to dinner, all ate same e.g people invited to dinner, all ate same food, all get food poison, all report to hospital at the same food, all get food poison, all report to hospital at the same time.time.

- Continuous sourceContinuous source: : one same sourceone same source

like the story of water source in London.like the story of water source in London.

OR shawarma cook has salmonella , every day he will transmit OR shawarma cook has salmonella , every day he will transmit the disease to some one, continuously from same source. the disease to some one, continuously from same source.

- 2.Propagated epidemic2.Propagated epidemic: : not same sourcenot same source- people got dystenry, they treated, but one of them partially people got dystenry, they treated, but one of them partially

recovered, we to al ain, transmit the disease to other recovered, we to al ain, transmit the disease to other group, this group treated, but one transmitted to other group, this group treated, but one transmitted to other group and so on.group and so on.

- Slow epidemicSlow epidemic- Investigation of outbreakInvestigation of outbreak

Investigation of outbreakInvestigation of outbreak1.1. Verification of diagnosis: confirm DxVerification of diagnosis: confirm Dx2.2. Confirm the existence of an out break: Confirm the existence of an out break: No. exceed expectedNo. exceed expected

3.3. Defining the population at risk: Defining the population at risk: case definitioncase definition

4.4. Rapid search for all cases and their characteristics Rapid search for all cases and their characteristics

5.5. Evaluation of ecological factors: cause of the problemEvaluation of ecological factors: cause of the problem6.6. Formulation of hypothesis: Formulation of hypothesis: dystentry from water source in dystentry from water source in

khawaneejkhawaneej

7.7. Testing hypothesis: Data analysis: Testing hypothesis: Data analysis: odds ratio, epidemic odds ratio, epidemic curvecurve

8.8. Control and prevention: actionControl and prevention: action

9.9. Final report: recommendationFinal report: recommendation

Steps by AmeeraSteps by Ameera

1.1. Confirm the DxConfirm the Dx

2.2. Make sure it is an out breakMake sure it is an out break

3.3. Make Make case definition case definition and search for the and search for the casescases

4.4. Put the hypothesis: the cause is ….Put the hypothesis: the cause is ….

5.5. Test the hypothesis: collect the data and Test the hypothesis: collect the data and analyze, odds ration, epidemic curveanalyze, odds ration, epidemic curve

6.6. Develop and implement control and Develop and implement control and prevention prevention

7.7. Report.Report.

EndemicEndemic

Continuous presence of a disease or Continuous presence of a disease or infectious agent within a given infectious agent within a given geographical areageographical area

e.g. TB in Indiae.g. TB in India - - Hyper-endemicHyper-endemic Expresses a persistence intense Transmission Expresses a persistence intense Transmission

- - Holo-endemicHolo-endemic A high level of infection beginning early in life which affect A high level of infection beginning early in life which affect

most population.most population.

Control Vs EradicationControl Vs Eradication

Control:Control: It is It is reduction reduction of the disease transmission to of the disease transmission to

an an acceptable minimumacceptable minimum, or to a , or to a level not be level not be considered a major public health problemconsidered a major public health problem

Eradication:Eradication: Complete elimination Complete elimination of a disease, or of a disease, or

complete cessation of transmission complete cessation of transmission and and infectious agentinfectious agent

Communicable diseaseCommunicable disease every communicable d. is infectiousevery communicable d. is infectious A disease capable of being transmitted from an A disease capable of being transmitted from an

infected person or species to a susceptible host, infected person or species to a susceptible host, either directly or indirectly.either directly or indirectly.

Carrier Carrier carry disease without symptoms : HIVcarry disease without symptoms : HIV

A person or animal that harbors a specific infectious A person or animal that harbors a specific infectious agent in the absence of clinical disease and serve as agent in the absence of clinical disease and serve as a potential source of infection.a potential source of infection.

Contact Contact A person or animal that has associated with an A person or animal that has associated with an

infected person or animal that might provide an infected person or animal that might provide an opportunity to acquire the infection.opportunity to acquire the infection.

Infectious diseaseInfectious disease: disease caused by infectious agent: disease caused by infectious agent

DisinfectionDisinfection

Killing of infectious agents Killing of infectious agents outside the body outside the body by direct by direct exposure to chemical or physical agents. exposure to chemical or physical agents.

High level disinfections refers to the inactivation of all High level disinfections refers to the inactivation of all microorganisms except some bacterial spores.microorganisms except some bacterial spores.e.g. e.g. what we do at home: cleaningwhat we do at home: cleaning

Concurrent disinfectionConcurrent disinfection Immediate disinfections and disposal of discharges Immediate disinfections and disposal of discharges

and infective matter all through the course of a and infective matter all through the course of a disease.disease.

Concept of communicabilityConcept of communicability Infectivity:Infectivity: Ability of the infective agent to enter, Ability of the infective agent to enter,

survive, and multiply in the host survive, and multiply in the host He has the disease but not showing S&SHe has the disease but not showing S&S Pathogenicity: Pathogenicity: cause destruction of organscause destruction of organs

The property of an organism that determines The property of an organism that determines the extent to which overt disease is produced the extent to which overt disease is produced in an infected population i.e the power of an in an infected population i.e the power of an organism to cause diseaseorganism to cause disease

Virulence:Virulence: The degree of pathogenicity, it is the The degree of pathogenicity, it is the

disease-evoking power of the organism in a disease-evoking power of the organism in a given host given host

Measures of MorbidityMeasures of Morbidity

1. Incidence: 1. Incidence: new cases, need immediate action, new cases, need immediate action, it measure riskit measure risk

2. Prevalence : 2. Prevalence : existing cases: new & old: used existing cases: new & old: used to plan for future, measure magnitude of diseaseto plan for future, measure magnitude of disease

3. Attack rate: 3. Attack rate: forfor primary casesprimary cases

• Index case: Index case: first person report health services first person report health services (went to hospital)(went to hospital)

• Primary cases: Primary cases: people who first exposed people who first exposed directly to the source of infectiondirectly to the source of infection

4. Secondary attack rate4. Secondary attack rate• Secondary cases Secondary cases :who got the disease but :who got the disease but

didn’t expose to the source of infection, bur didn’t expose to the source of infection, bur from the primary casesfrom the primary cases

• Why we calculate the 2ndy Attack rate:Why we calculate the 2ndy Attack rate: To know the infectivity(communicabilty) of the To know the infectivity(communicabilty) of the

disease .i.e. if it is infectious or not.disease .i.e. if it is infectious or not.

Measures of MortalityMeasures of Mortality1.1. Crude death rates : Crude death rates : all death in dubai, it is not all death in dubai, it is not

accurate , can’t be used for comparison, to make it better accurate , can’t be used for comparison, to make it better we have we have standardized itstandardized it

2.2. Specific death ratesSpecific death rates

3.3. Standardized ratesStandardized rates

4.4. Case fatality ratesCase fatality rates: : فتكا فتكا اكثر اكثر

5.5. Proportionate mortality ratio :Proportionate mortality ratio : اكثر اكثرالوفاة في الوفاة تسببا في e.g.We have 10 diseases causes e.g.We have 10 diseases causes تسببا

death, breast cancer PMR is the highestdeath, breast cancer PMR is the highest

6.6. Fetal and maternal mortality rateFetal 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

Epidemiologist is involved during the entire time from exposure and disease.

Randomized Trial

Define treatment and control groups.

Follow through time and compare rate of disease in treatment group with rate of disease in control group.

Administer exposure to treatment group, but not controls.

What’s the Design?

Epidemiologist is involved during the entire time from exposure and disease.

Cohort Study

Select a healthy study sample.

Follow through time and compare rate of disease in exposed group to rate of disease in unexposed group.

Observe who is exposed and who is not exposed.

What’s the Design?

Epidemiologist is involved after disease has occurred and relies on subjects’ memories to gather information about exposure.

Case-Control Study

Select a group of people with disease and a similar group of people without the disease.

Compare proportion of exposure in diseased group to proportion of exposure in non-diseased group.

Ask both groups about their exposures in the past.

What’s the Design?

What’s the Design?

Cross-Sectional Study

Ask each person about both exposure and disease at that point in time.

Epidemiologist gathers data only at that one point in time.

Disease rate in exposed group is compared to disease rate in unexposed group.

Select a study sample.