Preventive Medicine Part Ia

MEDPRIME REVIEW CENTER BAGUIO CITY Review Questions for Discussion on Preventive Medicine Dr. Jose Ronielo Juangco, MD, MPH, FPSVI UERMMMCI College of Medicine Assistant Professor Dr. Miguel Noche

Dr. Edgardo Fernando

Dr. Eleanor Almoro

Dr. Maria Graciela Gonzaga

Dr. Clarita Maano Dr. Eleanor Galvez

Chairman PEDIATRICIAN UST Interim Member OB GYNE Our Lady of Lourdes Hospital Medical City OB GYNE Saint Luke’s College of Medicine INTERNAL MEDICINE Professor and Dean UST DERMATOLOGIST UP-PGH DEAN PLM

Board members divide the 12 subjects Each submits 1000 questions per subject Sometimes members ask medical schools to submit questions (leakage) Computer randomly picks 100 questions per subject Members of the board incarcerated in a room inside PRC building during the exam guarded by the NBI Physicians’ Licensure Examination Deadline: August 22, 2016 September 10, 11, 17 and 18 Baguio, Manila, Cebu and Davao February 15, 2016 March 6, 7, 13 and 14 EPIDEMIOLOGY - Epidemiologic basics - Natural history of Disease - Outbreak Response - Levels of Prevention Broad Categories of Epidemiology A. Descriptive Epidemiology - Study of the amount/ frequency and distribution of disease, etc. in populations B. Analytic Epidemiology - Study of determinants or etiology of disease and related conditions 1. This is the branch of medicine that deals with the study of causes, distribution, and control of diseases in populations: C. EPIDEMIOLOGY 2. What does Epidemiology study? D. THE DISTRIBUTION AND DETERMINANTS OF FREQUENCY OF DISEASE IN HUMAN POPULATION 3. The London Cholera epidemic of 1848 was traced to the Broad street pump by JOHN SNOW JOHN GRAUNT

WILLIAM FARR

HIPPOCRATES

Father of Epidemiology Cholera Epidemic in London Bills of Mortality  reason why we are signing the death certificates, Top 10 cases of mortality Father of modern vital statistics International Classification of diseases (author of ICD-1) First Epidemiologist

BRADFORD HILL

Described diseases from a rational point of view Causal analysis Smoking and lung cancer

4. The epidemiologic triad shows the interaction of C. ENVIRONMENT, AGENT, and HOST Ecological triad Agent – Host – Environment (Vector in the middle) Homeostatic Balance * At equilibrium – Healthy individual * Agent becomes more pathogenic – The disease will be more virulent * If the host becomes more susceptible – Disease will also ensue - Immunocompromised host – increased susceptibility * Environmental changes that affects agent and host – will bring brought about other diseases - Rainy season – Dengue Fever is more prevalent - Brings down immune system of host 5. The natural history of a disease process commences with A. INTERACTION OF THE HOST AND DISEASE AGENT FACTORS WITH THE ENVIRONMENT Factors affecting Disease Causation A. Predisposing factors – Age, Sex, and previous illness B. Enabling factors – Low income, poor nutrition, bad housing, inadequate medical care C. Precipitating factors – Exposure to a specific disease agent or noxious agent D. Reinforcing factors – Repeated exposure, unduly hard work AGENT - Any element substance, or force whether living or non-living, the presence or absence of which can initiate or perpetuate a disease process - Characteristics - Inherent - Directly related to man 1. Infectivity – Ability to gain access 2. Pathogenicity – Ability to set up a specific reaction, local or general, clinical or subclinical 3. Virulence – Severity of reaction produced measured in terms of mortality 4. Antigenecity – Ability to stimulate the host to produce antibodies * Agent with high infectivity and pathogenicity but low antigenicity will cause a relatively high disease prevalence in the community * Agent with high infectivity but low pathogenicity usually produce a mild or sub clinical symptom and carrier - Related to environment Types of Agents Biological Chemical Physical Helminths Foods Heat Protozoans Poisons Light/ Radiation Fungi Drugs Noise Bacteria Allergens Vibration Rickettsia Objects Viral Prion Tropism - The agent preference to attack and stay in special location in the host - Cholera: Digestive tract - Staphylococcus: Mostly in the skin - Herpes Zoster: Nervous system - Poliomyelitis: Anterior-horn cells of the Spinal cord Host Factors

PREVENTIVE MEDICINE REVIEWER BY DR. JUANGCO | Encoded by KPCQ “We are ONE HELL OF A BATCH!” FLY BATCH 2015!

1. 2. 3. 4. 5.

Age – extremes of age – more susceptible to get disease Sex Race Culture Defense mechanism

11. The term epidemic is defines as A. AS THE OCCURRENCE OF CASES IN EXCESS OF WHAT IS NORMALLY EXPECTED IN A COMMUNITY OR REGION Is spreading through human populations across a large region, for instance, multiple continents or even worldwide – Pandemicity

Environment 1. Climate 2. Geography 3. Biologic Environement 6. Which among the factors below in determining the nature of the infection of the infection is a measure of the severity of disease, which can vary from very low to very high? B. VIRULENCE

Sporadic – Some surges of disease but does not surpass previous number of cases Endemic – sustained moderate to high level of cases in a community Epidemic – more cases now compared to last year (more than 1 focus for source of infection) Pandemic – nations, continents are already involved Outbreak – Only 1 focus of the source of infection

7. Which among the following is an important source of infection maybe an infected person who shows no evidence of clinical disease? C. CARRIER

12. The following is true regarding the behaviour of diseases in the community C. ENDEMIC REFERS TO THE PERSISTENT OCCURRENCE OF A DISEASE IN A PARTICULAR AT REGULAR INTERVAL

8. Which of the following transmissions occurs through contaminated materials, such as food, clothes, bedding and cooking utensils? B. INDIRECT TRANSMISSION

WHO Pandemic Alert Scale Phase I to III – mostly affected are animals Phase IV – Human to human transmission is seen Phase V – One WHO region is affected by disease Phase VI – Two or more WHO regions are affected by disease a. This choice is Phase 6 Pandemic alert scale b. Sporadic should have an irregular pattern d. Outbreak is the behaviour of disease who has a focal source of infection

9. An 18 year old male works in a company where lunches are often catered. One day, the water at the company facility is not working, but they managed to have lunch anyway. Two weeks later, he becomes sick. He develops anorexia, nausea, malaise and jaundice. During the course of the next four weeks, seven people who shared in the lunch becomes ill with similar symptoms. After a few weeks, each of the seven people completely recovers and they replace their caterer. The period between infection and clinical onset of the disease is termed as? C. INCUBATION PERIOD 10. Predisposition and susceptibility to a disease is observed at which stage of a disease’s natural history? A. PREPATHOGENESIS Incubation Period - Virulence, dose and portal of entry - Host and defense mechanisms - Identify of point source propagated epidemics - Tracing the course of infection and epidemic * Importance of Incubation Period - Tracing the source of infection and contact - Period of surveillance - Immunization - Identification of point source of propagated epidemics Communicable period - It is defined as the time during which an infectious agent may be transferred directly or indirectly from an infected animal to man, or from an infected person to an animal, including arthropods Herd Immunity - The resistance of a group to invasion and spreading of an infectious agent based on the resistance to an infection of a high proportion of individual members of the group Prodrome Consists of mild non-specific signs and symptoms

Frank Illness Signs and symptoms are now more specific

Chronic stage Disease is prolonged

(Generalized body weakness, fever)

(Icteresia, hemoptysis, paroxysmal nocturnal dyspnea)

(Development of anemia due to CKD secondary to uncontrolled HPN and DM)

10 Steps in an Outbreak Investigation 1. Prepare for field work - When the DOH is called upon due to an outbreak, we ready for the investigation (2 boxes which contains microscopes, instruments, etc.) 2. Establish the existence of an outbreak - Ask the local health officer  incidence of the disease of the same month last year (More cases now than last year = Outbreak) 3. Verify the diagnosis - Medical technologists will look at cultures, look at possible causes like water or soil 4. Define and identify the cases Confirmed: usually has laboratory verification Probable: usually has clinical features without lab verification Possible: usually has fewer of typical clinical features 5. Describe and orient the data in terms of time, place and person - Spot map is done putting in people who are involved to locate which area is the disease more prevalent 6. Develop hypotheses 7. Evaluate the hypotheses - Either case control or cohort (more of case control study) 8. Refine hypotheses and carry out additional studies 9. Implementing control and prevention measures - Only after you have shown or identified the source of the outbreak will you be allowed to do interventions and control of the disease 10. Communicate findings Point epidemic – only have one source, sudden rise and sudden drop

PREVENTIVE MEDICINE REVIEWER BY DR. JUANGCO | Encoded by KPCQ “We are ONE HELL OF A BATCH!” FLY BATCH 2015!

* Example is when in a community, the source of water comes from a water district and it is contaminated (continuous exposure) 16. If quarantine is necessary to contain an outbreak/epidemic, who of the following should be quarantined? D. SUSPECTS * Isolate the cases and quarantine the suspects Isolation – separation for the period of communicability of infected person Quarantine – Restriction of activity during the periods of communicability of well persons who have been exposed Propagating epidemic – from one source will infect other people then will infect other people, etc. Will start little, then there will be slight increase, and as the outbreak continues, people infected are noted to slightly decrease overtime

17. What is the graphical presentation of data most useful in locating cases during an epidemic? A. SPOT MAP 18. What is the first step in an epidemiologic/ outbreak investigation? C. DETERMINE EXISTENCE OF THE EPIDEMIC * Ideally it should be Prepare for Field work

Outliers = cases that stand apart * Early case may represent: - A background (unrelated) case - A source of epidemic (index) - An early exposure * Late cases may be: - Unrelated - Have long incubation periods - Indicate later exposure - Secondary cases * Time Trends A. Secular – time trends that are longer in nature (decades) - Heart diseases, Diabetes Mellitus, Cancer B. Cyclic – time trends where there is a number of interval between outbreaks - Dengue before was noted to have outbreaks every 3 years C. Seasonal – time trends that are related to the seasons - Summer – more skin diseases D. Attention phenomenon – there is increase in cases but does not warrant any investigation 13. What are changes in disease frequency usually encompassing several decades? B. SECULAR 14. To establish the existence of an outbreak/ epidemic, which of the following should be done? C. COMPARE THE PRESENT INCIDENCE WITH THE NORMAL EXPECTANCY 15. What is the type of outbreak where exposure is brief and all cases develop within one incubation period of the disease? C. POINT SOURCE OUTBREAK a. common source outbreak with intermittent exposure * Example is when in a community, the source of water is from a nearby waterfalls and at the top of the waterfall, sometimes there are people that defecate polluting the source of water of the community (intermittent because not always that the people upstream are defecating) b. common source outbreak with continuous exposure  increasing trend with noted plateau

19. What level of prevention aims to avoid the emergence and establishment of the social, economic and cultural patterns of living that are known to contribute to an elevated risk of disease? A. PRIMORDIAL LEVEL OF PREVENTION - Before the interaction of the agent, host and environment - Community based prevention Primary – during the interaction of the agent, host and environment - Individual based prevention - Prevent the initiation or onset of disease Prepathogenesis

Pathogenesis early Secondary - Early diagnosis - Prompt treatment

Pathogenesis late Tertiary - Disability limitation - Rehabilitation

Primary - Health Promotion - Specific Protection Primordial (even before prepathogenesis) 20. Pap Smear is an example of what level of prevention? C. SECONDARY LEVEL OF PREVENTION

Primary Level of Prevention 1. Health Promotion - Health education in the fundamental facts of health and disease - Good standards of nutrition - Inculcation of healthy living habits - Adequate housing recreations - Improvement and protection water supply systems - Improvement of environmental sanitation 2. Specific Protection - Segregation - Control of means of spread - Vector control - Increasing resistance - Immunization - Chemoprophylaxis - Mechanical factors * Malaria Chemoprophylaxis Chloroquine and Mefloquine – taken once weekly, and safe for pregnant women Doxycycline – taken daily, tends to be the least expensive antimalarial drug 21. Which level of prevention is aimed at reducing the progress or complications of established disease and is an important aspect of therapeutic and rehabilitation medicine? D. TERTIARY LEVEL OF PREVENTION 22. Which of the following statements regarding herd immunity is FALSE?

PREVENTIVE MEDICINE REVIEWER BY DR. JUANGCO | Encoded by KPCQ “We are ONE HELL OF A BATCH!” FLY BATCH 2015!

B. HI causes the prevalence of the organism in the population to plateau, but it will NEVER decline

d. Herd immunity – The disease has a low occurrence among the native inhabitants and a high occurrence among the migrants

23. Susceptibility of a host to a disease can be best altered or controlled through: C. BUILDING IMMUNE SYSTEM AND RESISTANCE TO AGENTS OF DISEASES

23. What is the reason why death rates are higher for males than females throughout life? D. ALL OF THE ABOVE

* Which of the following defines a local place variation of disease B. THE DISEASE HAS A HIGH OCCURRENCE IN BOTH THE NATIVE INHABITANTS AND MIGRANTSTO THE PLACE a. Cultural variation – The disease has a high occurrence in the native inhabitants but not among the immigrants c. Genetic immunity – The disease will continue to have a high occurrence among the offspring of the native inhabitants who have migrated out of the area

PREVENTIVE MEDICINE REVIEWER BY DR. JUANGCO | Encoded by KPCQ “We are ONE HELL OF A BATCH!” FLY BATCH 2015!