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Community Medicine / PSM - Complete Exam Guide

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UNIT 1 - Demography & Vital Statistics (10 marks)

What is Demography?

• Census - Official counting of a population (done every 10 years in India; last full census was 2011)
• Population growth rate - How fast a population increases
• Demographic transition - The shift from high birth + high death rates → low birth + low death rates (4 stages)

Demographic Transition Theory (Important for Exams!)

Vital Statistics

• Crude Birth Rate (CBR) = (Live births / Mid-year population) × 1000
• General Fertility Rate (GFR) = (Live births / Women aged 15-44) × 1000
• Total Fertility Rate (TFR) = Average number of children a woman has. India's TFR ~2.0 (as of recent data)

• Crude Death Rate (CDR) = (Deaths / Mid-year population) × 1000
• Infant Mortality Rate (IMR) = (Deaths under 1 year / Live births) × 1000 → Best indicator of community health
• Neonatal Mortality Rate = Deaths in first 28 days per 1000 live births
• Perinatal Mortality Rate = Stillbirths + Deaths in first 7 days per 1000 births
• Maternal Mortality Rate (MMR) = Maternal deaths per 100,000 live births
• Under-5 Mortality Rate (U5MR) = Deaths under age 5 per 1000 live births

• Life expectancy at birth - Average number of years a newborn is expected to live
• Natural increase = Birth rate - Death rate
• Net Reproduction Rate (NRR) - If NRR = 1, population is replacing itself

• Civil Registration System (CRS) - Register births/deaths
• Sample Registration System (SRS) - Large-scale sample survey for vital rates
• Census - every 10 years

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UNIT 1 (continued) - Reproductive, Maternal & Child Health (20 marks)

Reproductive Health

• Family planning
• Safe motherhood
• Prevention of STIs/HIV
• Adolescent health

Maternal Health

• At least 4 ANC visits recommended (WHO recommends 8 contacts now)
• Registration before 12 weeks of pregnancy
• Key ANC components (3T's): Tetanus toxoid, Iron + Folic acid, Treatment of anemia + infections
• Danger signs in pregnancy: Severe headache, blurred vision, edema, bleeding, reduced fetal movements

• 100mg elemental iron + 500mcg folic acid daily for at least 100 days from 2nd trimester

• TT1 - early pregnancy; TT2 - 4 weeks after TT1; Booster if previously vaccinated

• Leading causes: Hemorrhage (most common globally), Sepsis, Hypertensive disorders, Unsafe abortion
• India's MMR has dropped significantly but remains high in rural areas

• Janani Suraksha Yojana (JSY) - Cash incentive for institutional deliveries
• Pradhan Mantri Suraksha Matritva Abhiyan (PMSMA) - Free ANC on 9th of every month
• Janani Shishu Suraksha Karyakram (JSSK) - Free delivery, free C-section, free transport
• LaQshya - Labour room quality improvement initiative

Child Health

1. Pneumonia
2. Diarrhea
3. Malaria
4. Measles
5. Malnutrition

• Weight for age plotted on Road-to-Health card
• MUAC (Mid-Upper Arm Circumference): <11.5 cm = Severe Acute Malnutrition (SAM); 11.5-12.5 cm = Moderate
• Growth Faltering - failure to gain expected weight

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UNIT 1 (continued) - Nutrition (10 marks)

Classification of Nutrients

• Macronutrients: Carbohydrates, Proteins, Fats
• Micronutrients: Vitamins, Minerals

Protein-Energy Malnutrition (PEM) - Very Important!

Micronutrient Deficiencies

National Nutritional Programmes:

• Mid-Day Meal Scheme - Hot cooked meals to school children
• ICDS (Integrated Child Development Services) - 0-6 year olds + pregnant/lactating mothers; supplementary nutrition, immunization, health checkup at Anganwadi centres
• National Iron Plus Initiative - IFA supplementation across all age groups
• Vitamin A Supplementation - 6-59 months, every 6 months

Assessment of Nutritional Status (ABCD method):

• A - Anthropometric (weight, height, MUAC, skinfold thickness)
• B - Biochemical (serum albumin, hemoglobin)
• C - Clinical (signs and symptoms)
• D - Dietary (24-hour recall, food frequency questionnaire)

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UNIT 2 - Concept of Health and Disease + History of Medicine (15 marks)

Definitions of Health

• Criticism: Utopian, static, difficult to measure

Spectrum of Health and Disease

Optimal Health → Good Health → Average Health → Poor Health → Disease → Death

1. Stage of Susceptibility - Risk factors present, no disease yet
2. Stage of Pre-symptomatic Disease - Pathological changes started, no symptoms
3. Stage of Clinical Disease - Symptoms appear
4. Stage of Disability/Death - Complications or recovery

Levels of Prevention (Leavell & Clark)

History of Medicine (15 marks - read for your exam)

1. Primitive Medicine - Magic, supernatural beliefs, use of herbs
2. Ancient civilizations:
   • Indian (Ayurveda) - Sushruta (surgery), Charaka (medicine), Atharva Veda mentions diseases
   • Greek - Hippocrates (Father of Medicine); separated medicine from religion; "First do no harm"; introduced clinical observation
   • Roman - Galen; emphasized anatomy; organized public health (aqueducts, sewers)
3. Middle Ages - Church dominated; epidemics of plague ("Black Death")
4. Renaissance (16th-17th century) - Vesalius (anatomy), Harvey (circulation of blood)
5. Germ Theory Era (late 1800s):
   • Louis Pasteur - Germ theory, pasteurization, vaccines (rabies, anthrax)
   • Robert Koch - Koch's postulates, discovered TB bacillus and cholera vibrio
   • Joseph Lister - Antiseptic surgery
   • Edward Jenner - First vaccine (smallpox, 1796) - "Father of Immunology"
   • John Snow - Father of Epidemiology; traced cholera to Broad Street pump (1854)
6. Modern Medicine - Antibiotics (Fleming discovered penicillin 1928), social medicine, community health

• Disease control phase (1880-1920)
• Health promotion phase (1920-1960)
• Social engineering phase (1960-1980)
• Health for All phase (1981-2000) - Alma Ata Declaration 1978 (Primary Health Care)
• SDGs (2015-2030)

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UNIT 2 (continued) - Social & Behavioural Factors in Health (5 marks)

Social Determinants of Health (WHO)

• Income and social status - Poverty is the biggest determinant
• Education - Higher education = better health literacy
• Social support networks
• Culture and beliefs - Can promote or hinder health-seeking behavior
• Gender - Women face more barriers to healthcare
• Environment - Clean water, sanitation, housing

Key Behavioral Factors:

• Smoking - Leading preventable cause of cancer, CVD, COPD
• Alcohol use - Liver disease, accidents, domestic violence
• Diet - Obesity, diabetes, cardiovascular disease
• Physical inactivity - Non-communicable disease risk
• Sexual behavior - STI/HIV risk

Health Belief Model (Rosenstock)

1. They are susceptible to the disease
2. The disease is serious
3. Action would benefit them
4. Barriers to action are manageable

Sick Role (Parsons):

• Exempted from normal duties
• Not blamed for illness
• Expected to seek medical help
• Expected to want to recover

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UNIT 3 - General Epidemiology & Screening (15 marks)

What is Epidemiology?

• Describe the natural history of disease
• Identify causes/risk factors
• Measure disease burden
• Evaluate effectiveness of interventions

Epidemiological Triad

          HOST
         /    \
        /      \
   AGENT ---- ENVIRONMENT

• Agent - causative factor (bacteria, virus, chemical, etc.)
• Host - person at risk (age, sex, genetics, immunity)
• Environment - external factors (climate, sanitation, socioeconomic)

Measures of Disease Frequency

• Point prevalence - at one specific time
• Period prevalence - over a time period
• Prevalence is useful for planning services (how much disease is there?)

• Incidence is useful for identifying causes (who is getting the disease?)

Types of Epidemiological Studies

• Randomized Controlled Trial (RCT) - Gold standard; participants randomly assigned to treatment or control
• Field trial - Healthy people in field setting
• Community trial - Communities as units

Key Measures of Association:

• Relative Risk (RR) = Incidence in exposed / Incidence in unexposed (used in cohort studies)
• Odds Ratio (OR) = Used in case-control studies (approximates RR for rare diseases)
• Attributable Risk (AR) = Incidence in exposed - Incidence in unexposed
• If RR or OR >1 → risk factor; <1 → protective factor; =1 → no association

Screening

1. Disease must be an important health problem
2. There must be an acceptable treatment
3. Facilities for diagnosis and treatment must be available
4. There must be a latent/presymptomatic stage
5. There must be a suitable screening test
6. Test must be acceptable to the population
7. Natural history must be adequately understood
8. Agreed policy on who to treat
9. Cost of case-finding must be economically balanced
10. Case-finding must be a continuous process

• Mass screening - Entire population
• Selective/targeted screening - High-risk groups (e.g., diabetics for retinopathy)
• Multi-phasic screening - Multiple tests in one visit
• Opportunistic screening - During routine visit

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UNIT 3 (continued) - Basic Statistics & Applications (5 marks)

Types of Data:

• Qualitative (Categorical): Nominal (blood groups, gender), Ordinal (mild/moderate/severe)
• Quantitative (Numerical): Discrete (number of children), Continuous (height, weight)

Measures of Central Tendency:

• Mean = Sum / Number of values (affected by outliers)
• Median = Middle value when arranged in order (not affected by outliers; used for skewed data)
• Mode = Most frequently occurring value

Measures of Dispersion:

• Range = Max - Min
• Standard Deviation (SD) = Measures how spread out data is from the mean
• Variance = SD²
• Coefficient of Variation (CV) = (SD/Mean) × 100% - Useful for comparing variability between two different units

Normal Distribution (Bell Curve):

• Mean = Median = Mode
• 68% of values lie within ±1 SD
• 95% within ±2 SD (important for reference ranges!)
• 99.7% within ±3 SD

Hypothesis Testing:

• Null Hypothesis (H₀): No difference/association exists
• Alternative Hypothesis (H₁): Difference/association exists
• p-value: If p < 0.05, result is statistically significant (reject null hypothesis)
• Confidence Interval (CI): If 95% CI for RR or OR does not include 1.0, the result is significant

Common Statistical Tests:

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UNIT 4 - Environmental Health + Biomedical Waste (10 marks)

Environmental Health

Water

• Surface water (rivers, lakes) - needs treatment
• Ground water (wells, tubewells) - relatively safe
• Rain water - generally safe if properly collected

1. Storage & sedimentation - Physical removal of particles
2. Filtration - Slow sand filter (most effective biological treatment); Rapid sand filter (faster, needs coagulation)
3. Disinfection - Chlorination is the most common and cost-effective method
   • Residual chlorine in tap water = 0.5 mg/L
4. Coagulation - Adding alum (aluminum sulfate) to remove suspended particles

• Coliform count: 0 per 100 mL in treated water
• WHO Drinking Water Standards

Air Pollution

• CO (carbon monoxide) - from incomplete combustion; binds hemoglobin
• SO₂, NO₂ - acid rain, respiratory disease
• PM2.5, PM10 - particulate matter; deep lung penetration
• Lead - neurotoxicity, especially in children
• Ozone (ground level) - respiratory irritant

Soil/Excreta Disposal

• Sanitary latrines (pour flush latrine most common in India)
• Septic tanks
• Sewage treatment plants

• Pit latrine
• Pour flush latrine (most suitable for Indian conditions)
• Aqua privy

Biomedical Waste (BMW) Management - Important for Exam!

• Yellow waste → Incineration or deep burial
• Red waste → Autoclaving/microwaving then shredding
• Sharp waste → Encapsulation or plasma pyrolysis
• Blue waste → Autoclaving then shredding

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UNIT 4 (continued) - Disaster Management (5 marks)

Types of Disasters:

• Natural: Earthquakes, floods, cyclones, droughts, landslides, tsunamis
• Man-made: Industrial accidents, chemical spills, nuclear accidents, wars, terrorist attacks
• Biological: Pandemics, epidemics

Disaster Management Cycle:

PREVENTION → MITIGATION → PREPAREDNESS
                ↑                ↓
           RECOVERY ←  RESPONSE

1. Prevention - Stop disaster from happening (building codes, flood barriers)
2. Mitigation - Reduce impact (early warning systems, land-use planning)
3. Preparedness - Plan and prepare (training, stockpiling, drills)
4. Response - Actions during disaster (search & rescue, relief, medical care)
5. Recovery - Restore normalcy (reconstruction, rehabilitation)

Key Phases of Medical Response:

• Immediate phase (0-24 hrs) - Search & rescue, first aid, triage
• Short-term phase (24 hrs - 4 weeks) - Temporary shelter, clean water, prevent disease outbreaks
• Long-term phase (>4 weeks) - Reconstruction, mental health, rehabilitation

Triage (Mass Casualty Management):

• Red (Immediate) - Life-threatening but salvageable; treat first
• Yellow (Delayed) - Serious but stable; can wait
• Green (Minor/Walking wounded) - Minor injuries; treat last
• Black (Expectant/Dead) - Unsurvivable or dead; no treatment

National Disaster Management Authority (NDMA):

• Set up under the Disaster Management Act, 2005
• Chaired by the Prime Minister
• National Disaster Response Force (NDRF) - specialized response teams

Health Effects of Disasters:

• Acute: Trauma, drowning, burns, crush injuries
• Short-term: Diarrheal diseases, respiratory infections, malnutrition
• Long-term: Mental health disorders (PTSD, depression), chronic diseases

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UNIT 5 - AETCOM (5 marks)

Medical Ethics - 4 Principles (Beauchamp & Childress):

1. Autonomy - Patient's right to make informed decisions about their own care
2. Beneficence - Duty to do good for the patient
3. Non-maleficence - "First do no harm" (Primum non nocere)
4. Justice - Fair distribution of healthcare resources; treating all patients equally

Informed Consent:

• Must be voluntary (no coercion)
• Patient must be given adequate information (diagnosis, treatment options, risks, benefits)
• Patient must have decision-making capacity
• Special cases: minors (parent/guardian consent), unconscious patients (emergency exception)

Doctor-Patient Relationship:

• Paternalistic model - Doctor decides what's best (old model)
• Partnership/Autonomy model - Patient is involved in decision-making (modern, preferred model)

Communication Skills:

• Breaking bad news - Use the SPIKES protocol:
  • S - Setting (private, comfortable)
  • P - Perception (what does patient know already)
  • I - Invitation (ask how much they want to know)
  • K - Knowledge (give information clearly)
  • E - Empathy (acknowledge emotions)
  • S - Summary (plan what happens next)

Medical Confidentiality:

• Information shared with doctor must not be disclosed without consent
• Exceptions: Notifiable diseases (cholera, TB, COVID), court orders, imminent danger to others

Professionalism in Medicine:

• Honesty and integrity
• Respect for patients
• Maintaining competence
• Avoidance of conflict of interest
• Compassion and respect for diversity

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Quick Revision Summary (Marks Distribution)

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Top Exam Tips

1. RCH (20 marks) = Highest priority. Know all the national programmes by name, their benefits, and target populations.
2. Epidemiology (15 marks) = Focus on study designs, sensitivity/specificity, and measures of association.
3. History of Medicine (15 marks) = Memorize key names: Hippocrates, Pasteur, Koch, Jenner, Snow, Lister.
4. Levels of Prevention comes up in almost every PSM exam - know all 4 levels with examples.
5. Biomedical Waste color coding is a direct, frequently-asked question - memorize it.
6. Triage colors (Red/Yellow/Green/Black) are easy marks in Disaster Management.
7. AETCOM - Know the 4 ethical principles and SPIKES protocol.