Master PSM (Preventive Social Medicine)
for FMGE

What the FMGE Tests in PSM (Preventive Social Medicine)

The FMGE PSM section tests application of epidemiological principles to real-world clinical scenarios: outbreak investigation (cholera, measles), screening test interpretation (sensitivity, specificity, predictive values), and national health programme knowledge (RCH, NVBDCP, RNTCP). Candidates must demonstrate ability to calculate rates (IMR, MMR, CFR), apply immunization schedules (BCG at birth, OPV/IPV, DPT), and identify disease prevention levels (primordial, primary, secondary, tertiary). Key areas include biostatistics (t-test, chi-square, p-values), nutrition (vitamin deficiencies, PEM classification using IAP/WHO criteria), and environmental health (water purification methods, waste disposal). Emphasis is on Indian public health guidelines, ICD-10 coding for cause of death, and WHO growth standards.

High-Yield Concepts

• IMR and MMR Calculation: Infant Mortality Rate = (Number of deaths under 1 year / Total live births) × 1000. Maternal Mortality Ratio = (Maternal deaths / Live births) × 100,000. Current Indian IMR ~28, MMR ~97 (SRS 2018-20). Know that MMR includes deaths during pregnancy or within 42 days of termination.
• Screening Test Performance: Sensitivity = TP/(TP+FN); Specificity = TN/(TN+FP). Positive Predictive Value = TP/(TP+FP). For a rare disease, PPV drops sharply. Example: Mammography for breast cancer (sensitivity ~85%, specificity ~90%). Likelihood ratio >10 strongly rules in disease.
• WHO Growth Standards for Under-5: Stunting (height-for-age <-2SD), Wasting (weight-for-height <-2SD), Underweight (weight-for-age <-2SD). Severe acute malnutrition (SAM): MUAC <115 mm or weight-for-height <-3SD. Use WHO charts; IAP classification uses weight-for-age only.
• National Immunization Schedule (India): BCG, OPV 0, Hep B birth dose at birth; DPT, OPV, IPV, Hep B at 6, 10, 14 weeks; Measles/MR at 9-12 months; DPT booster at 16-24 months; TT for pregnant women (2 doses). Know catch-up for missed doses.
• Cholera Outbreak Investigation: Confirm with stool culture (TCBS agar) or rapid test. Immediate steps: isolate cases, give oral rehydration (WHO ORS), doxycycline for severe cases. Attack rate = (cases/population at risk) × 100. Secondary attack rate for household contacts.
• Vitamin Deficiency Syndromes: Vitamin A: night blindness, Bitot spots, keratomalacia; treatment: 200,000 IU oral (6-monthly for children). Vitamin B3 (Niacin): pellagra (dermatitis, diarrhea, dementia). Vitamin D: rickets (bowing, craniotabes); treat with 600,000 IU IM or oral weekly for 8 weeks.
• Water Purification Methods: Boiling (vigorous for 10-20 min) kills all pathogens. Chlorination: 0.5-1.0 mg/L residual free chlorine for household use; 2 mg/L for well disinfection. SODIS: UV exposure in PET bottles for 6 hours. For community: slow sand filtration (99% bacterial removal).
• NVBDCP Key Diseases: Malaria: RDT (Pf/Pv), artemisinin combination therapy (ACT) for Pf, chloroquine for Pv. Dengue: NS1 antigen, platelet count <100,000 signals severe dengue; no specific drug, fluid management. Kala-azar: splenic aspirate for LD bodies; treat with liposomal amphotericin B.

Common Traps in PSM (Preventive Social Medicine) Questions

• Confusing attack rate (cumulative incidence) with case fatality rate (deaths/cases × 100).
• Using weight-for-height for stunting assessment; stunting is height-for-age, not weight.
• Forgetting that sensitivity and specificity are independent of disease prevalence, but predictive values are not.
• Assuming all vaccines are given at exactly the same age; DPT and OPV have specific intervals (minimum 4 weeks between doses).
• Misapplying ORS composition: WHO ORS has 75 mmol/L sodium, 75 mmol/L glucose; homemade sugar-salt solution is 1 teaspoon salt + 8 teaspoons sugar per litre.
• Believing that boiling water for 1 minute is sufficient at high altitudes; it requires 3 minutes or more due to lower boiling point.

How to Revise PSM (Preventive Social Medicine) for the FMGE

Prioritise biostatistics (sensitivity, specificity, odds ratio, t-test) and national programmes (RCH, NVBDCP, RNTCP, NPCDCS) as they appear in 40% of PSM questions. Practice calculating rates from given numerators/denominators—common in short-answer formats. Focus on Indian immunization schedule and WHO growth standards, as these are frequently tested with age-based cut-offs. Review outbreak investigation steps (cholera, measles) and water purification methods. Questions often present a clinical vignette (e.g., child with wasting, village with diarrhea cases) and ask for the next management step or epidemiological measure. Rehearse interpreting 2x2 tables and identifying study designs (cohort, case-control, RCT).

Practise it: MedLumen has 52 PSM (Preventive Social Medicine) questions for the FMGE, each with a full explanation and references.