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PSM Final Prof MBBS - High-Yield Exam Questions & Answers

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TOPIC 1: EPIDEMIOLOGY & BIOSTATISTICS

Long Questions (10-mark / Essay type)

• Definition (IEA): "The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the prevention and control of health problems."
• Aims (IEA - 3 aims):
  1. Describe the distribution and magnitude of health and disease problems in human populations
  2. Identify aetiological factors (risk factors) in pathogenesis of disease
  3. Provide data for planning, implementation and evaluation of preventive services and setting priorities
• Epidemiology vs Clinical Medicine:

• Types of Epidemiological Studies: Descriptive, Analytical, Experimental

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• Epidemic: Occurrence in a community of cases clearly in excess of normal expectancy. Community + time period must be specified precisely.
• Endemic: Constant presence of a disease/infectious agent within a given geographic area without importation from outside. E.g., common cold.
• Hyperendemic: Disease constantly present at high incidence/prevalence, affects all age groups equally.
• Holoendemic: High level of infection beginning early in life, affecting most children; adults show less evidence due to equilibrium (e.g., malaria).
• Sporadic: Cases occur irregularly, haphazardly, widely separated in space and time, no connection with each other. E.g., tetanus, herpes zoster, meningococcal meningitis.
• Pandemic: Epidemic spread over several countries or continents, usually affecting a large number of people. E.g., COVID-19, influenza 1918.

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• Rate: Frequency of a disease or event divided by population at risk per unit time. Essential component: numerator, denominator, time period, multiplier (e.g., 1000 or 100,000).
  • e.g., Incidence rate, Mortality rate
• Ratio: Comparison of two quantities (not necessarily from same group). Numerator is not included in denominator. e.g., Sex ratio, Maternal mortality ratio.
• Proportion: Ratio in which numerator is included in denominator. Expressed as percentage. e.g., Proportional mortality rate, Case fatality rate.
• Scope of measurement includes:
  • Mortality, Morbidity, Disability, Natality
  • Distribution of disease characteristics
  • Health needs and utilization of services
  • Environmental factors
  • Demographic variables
• Requirements: Validity, reliability, accuracy, sensitivity, specificity.

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• Screening: Testing for infection or disease in populations who are NOT seeking health care (e.g., neonatal screening, blood donor testing for HIV).
• vs Case-finding: Detecting disease in individuals already seeking care for other reasons.
• vs Diagnostic test: Confirming/refuting disease in symptomatic patients.
• Uses of Screening:
  1. Case detection (Prescriptive screening) - for benefit of individual
  2. Control of disease (Prospective screening) - for benefit of others
  3. Research purposes
  4. Assessment of health status
• Wilson-Jungner Criteria (10 principles for a good screening program):
  1. Condition is an important health problem
  2. Natural history of condition is understood
  3. Early detectable stage exists
  4. Effective treatment available when diagnosed early
  5. Suitable test available
  6. Test acceptable to the population
  7. Adequate facilities to diagnose and treat
  8. Policy agreed on whom to treat
  9. Cost economically balanced against benefits
  10. Should be a continuing process (not "once and for all")
• Ideal screening test properties: High sensitivity, High specificity, High positive predictive value, Simple, cheap, acceptable, valid, reliable.

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Short Notes (5-mark)

• Sensitivity (True positive rate): Ability of test to correctly identify those WITH the disease. = TP / (TP + FN) × 100. High sensitivity → few false negatives → good for RULING OUT disease (SnNOut).
• Specificity (True negative rate): Ability to correctly identify those WITHOUT disease. = TN / (TN + FP) × 100. High specificity → few false positives → good for RULING IN disease (SpPIn).
• PPV: Probability that a positive test truly has disease.
• NPV: Probability that a negative test truly is disease-free.

• Incidence: Number of NEW cases occurring in a defined population during a specified time period. Measures risk. Useful for acute conditions.
• Prevalence: Number of ALL existing cases (new + old) at a point in time. Measures disease burden. Useful for chronic conditions.
• Relationship: Prevalence ≈ Incidence × Duration of disease.

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TOPIC 2: COMMUNICABLE DISEASES

Long Questions

• Causative agent: Mycobacterium tuberculosis
• Reservoir: Infected humans (primarily)
• Transmission: Droplet nuclei (airborne), rarely ingestion
• Incubation period: 4-12 weeks
• Period of communicability: As long as bacilli present in sputum
• High risk groups: HIV infected, malnutrition, diabetes, contacts of sputum positive cases

• BCG vaccination at birth (for infants)
• DOTS (Directly Observed Treatment Short course): Cornerstone of TB control
• Category I: New sputum positive/severe cases - 2(HRZE)/4(HR)
• Category II: Previously treated - 2(HRZES)/1(HRZE)/5(HRE)
• Contact tracing and chemoprophylaxis (Isoniazid preventive therapy for contacts)
• National Tuberculosis Elimination Programme (NTEP) - goal to eliminate TB by 2025

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• Agent: Plasmodium vivax (most common in India), P. falciparum (most dangerous - cerebral malaria)
• Vector: Female Anopheles mosquito (bites at dusk/dawn)
• Reservoir: Infected humans
• Incubation: P. vivax = 12-17 days; P. falciparum = 9-14 days
• Life cycle: Schizogony (asexual - in man), Sporogony (sexual - in mosquito)

1. Anti-larval measures: Drainage, larvivorous fish (Gambusia), larval oils
2. Anti-adult measures: DDT residual spray, pyrethrum
3. Personal protection: Bed nets (insecticide-impregnated), repellents
4. Chemoprophylaxis: Chloroquine (where sensitive)
5. Case treatment: Chloroquine + Primaquine (P. vivax); ACT - Artesunate combination (P. falciparum)
6. National Vector Borne Disease Control Programme (NVBDCP)

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• The Epidemiological Triad = Agent + Host + Environment
• Disease occurs when there is imbalance between these three components
• Agent: Biological (bacteria, virus, parasite), Chemical, Physical, Nutritional
• Host factors: Age, sex, genetic factors, immunity, nutrition, habits
• Environmental factors: Physical (climate), Biological (vectors, reservoirs), Social (overcrowding, sanitation)
• Modes of Transmission: Direct (contact, droplet, transplacental), Indirect (vehicle, vector-borne, airborne, fomite)

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Short Notes

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TOPIC 3: NATIONAL HEALTH PROGRAMS

Long Questions

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• R (Reproductive health): Family planning services, contraception
• M (Maternal health): ANC (minimum 4 visits), institutional delivery, skilled birth attendant, PostNatal Care
• N (Newborn): Essential Newborn Care, SNCU (Special Newborn Care Unit), Kangaroo Mother Care
• C (Child health): IMNCI, nutrition, VHND (Village Health Nutrition Day)
• +A (Adolescent): RKSK (Rashtriya Kishor Swasthya Karyakram), WIFS (Weekly Iron Folic Acid Supplementation)

• MMR target < 100/lakh live births
• IMR target < 30/1000 live births
• U5MR target < 40/1000 live births

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• Launched 1952 - World's first national family planning program
• Target Free approach since 1996 (from target-based to community-needs assessment)
• Methods: OCP, IUCD (Cu-T 380A, PPIUCD), Tubectomy, Vasectomy, Condom, DMPA (injectable), Centchroman (Chhaya)
• Mission Parivar Vikas (2016): High focus districts for improving FP services
• ANMOL app: For digitizing health worker data
• Eligible Couple Register at sub-centre level

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TOPIC 4: ENVIRONMENT & OCCUPATIONAL HEALTH

Long Questions

1. Sedimentation - Removal of suspended particles by gravity (plain/assisted with alum)
2. Coagulation/Flocculation - Adding alum (Al2SO4), forms floc which settles
3. Filtration - Slow sand filter (most effective for bacteria removal, 99%) vs Rapid sand filter
4. Disinfection - Chlorination: Breakpoint chlorination, residual chlorine = 0.5 mg/L after 1 hour contact time; also UV, Ozone

• Bacteriological: E. coli count (most important indicator of fecal contamination); Total coliform count
• Physical: Color, turbidity, odor, taste
• Chemical: pH, hardness, nitrates, fluoride (0.5-0.8 ppm ideal), chloride

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• Definition: Lung diseases caused by inhalation of dust in occupational settings
• Types:

• Silicosis - MOST IMPORTANT:
  • Irreversible fibrosis; no specific treatment
  • Associated with TB (silicotuberculosis)
  • Eggshell calcification of hilar nodes on X-ray
  • Prevention: Dust suppression, substitution, PPE, pre-employment screening

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Short Notes

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TOPIC 5: NUTRITION, MCH & FAMILY PLANNING

Long Questions

• Grade I: 71-80% (Mild)
• Grade II: 61-70% (Moderate)
• Grade III: 51-60% (Severe)
• Grade IV: <50% (Very severe)

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• Sub-centre: ANM provides MCH services - ANC registration, immunization, IUD insertion, weighing of children
• PHC: Medical officer + staff nurse; MCH clinic
• CHC/FRU: Comprehensive Emergency Obstetric Care (CEmOC)

• Registration by 12 weeks
• Investigations: Hb, Blood group, VDRL, HIV, urine albumin/sugar, BP
• Supplements: IFA (100 mg iron + 500 mcg folic acid × 180 days), Calcium 1g/day
• TT immunization
• High-risk screening: PIH, GDM, anemia, malpresentation

1. Delay in deciding to seek care
2. Delay in reaching facility
3. Delay in receiving adequate care

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Short Notes

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TOPIC 6: SOCIAL MEDICINE & HEALTH ADMINISTRATION

Long Questions

• "Health for All by 2000" - WHO/UNICEF
• PHC is essential health care based on practical, scientifically sound and socially acceptable methods
• Accessible, affordable, universally available

1. Education about health problems and prevention
2. Nutrition and food supply promotion
3. Safe water and basic sanitation
4. Maternal and Child Health including Family Planning
5. Immunization against major infectious diseases
6. Prevention and control of endemic diseases
7. Appropriate treatment of common diseases and injuries
8. Provision of essential drugs

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• Peripheral-most outpost of health system
• Population: 3,000 (plains) / 1,000 (hilly/tribal/difficult areas)
• Staff: 1 ANM (Female Multi-Purpose Worker) + 1 Male MPW
• Key functions: MCH, family planning, immunization, first aid, health education, IEC, nutrition surveillance

• Population: 20,000-30,000 (plains) / 3,000-20,000 (hilly)
• Staff: 1 Medical Officer + 14 paramedical/other staff
• 6 sub-centres under 1 PHC
• Functions: OPD, preventive & promotive services, MCH/FP, immunization, disease control, health education, referral, training

• Population: 80,000-1,20,000
• Staff: 4 specialists (Surgeon, Physician, Gynecologist, Pediatrician) + 21 paramedical staff
• 30 beds + OT + 24-hour delivery + blood storage

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• Dubos: "A modus vivendi enabling imperfect men to achieve a rewarding and not too painful existence"
• Biomedical model vs Social model vs Ecological model

1. Mortality indicators: CDR, IMR, U5MR, MMR, Life expectancy, PYLL
2. Morbidity indicators: Incidence, Prevalence, Attack rate, Disability rate
3. Disability indicators: Sullivan's Index, DALY, QALY
4. Nutritional indicators: Anthropometric measurements, BMI
5. Health care delivery indicators: Doctor:population ratio, bed:population ratio, nurse:population ratio
6. Socioeconomic indicators: Per capita income, literacy rate, HDI, GNP
7. Social indicators: Fertility rate, family size
8. Composite indicators: HDI, PQLI (Physical Quality of Life Index), HFA indicators

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Short Notes (Important ones)

• Primordial: Preventing emergence of risk factors (e.g., tobacco control policies)
• Primary: Preventing disease before it occurs: Health promotion + Specific protection (vaccination)
• Secondary: Early diagnosis and prompt treatment (screening)
• Tertiary: Reducing disability and rehabilitation

• Community health worker under NHM (2005)
• Female, resident of village, class 8 educated
• Population: 1 per 1000 population
• Roles: Link between community and health system, motivate for institutional delivery, immunization, family planning
• Incentive-based (not salaried)
• ASHA drug kit available

• MDGs: 2000-2015, 8 goals. Key health goals: Reduce child mortality (Goal 4), Improve maternal health (Goal 5), Combat HIV/AIDS, malaria, other diseases (Goal 6)
• SDGs: 2015-2030, 17 goals. Goal 3: "Ensure healthy lives and promote well-being for all at all ages" - includes UHC, ending AIDS, TB, malaria, reducing NCDs, mental health.

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QUICK REVISION CHEAT SHEET - HIGH-YIELD NUMBERS

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EXAM STRATEGY TIPS

1. Epidemiology questions - always define first, then classify, then elaborate with examples.
2. Communicable disease questions - use the SEPM framework: Source/Agent → Epidemiology (host, environment, transmission) → Prevention → Management.
3. Health program questions - mention the Ministry, year launched, target population, key interventions, key indicators.
4. Nutrition questions - always draw the classification table (Wellcome/IAP).
5. 5-mark shorts - aim for 5-6 points, each with a brief explanation (not just a list).
6. Draw tables and diagrams wherever possible - examiners reward visual organization.