Key Clinical Formulas
Body Mass Index (BMI): BMI = weight(kg) / height(m)²
Underweight <18.5 | Normal 18.5-24.9 | Overweight 25-29.9 | Obese ≥30
Underweight <18.5 | Normal 18.5-24.9 | Overweight 25-29.9 | Obese ≥30
Framingham Risk Score: 10-year CVD risk using age, cholesterol, BP, smoking, diabetes
Low <10% | Intermediate 10-20% | High ≥20%
Low <10% | Intermediate 10-20% | High ≥20%
CHAâ‚‚DSâ‚‚-VASc (Stroke risk in AF):
CHF=1, HTN=1, Age≥75=2, DM=1, Stroke/TIA=2, Vascular=1, Age 65-74=1, Sex female=1
Score ≥2: anticoagulate; 1: consider; 0: no anticoagulation
CHF=1, HTN=1, Age≥75=2, DM=1, Stroke/TIA=2, Vascular=1, Age 65-74=1, Sex female=1
Score ≥2: anticoagulate; 1: consider; 0: no anticoagulation
Wells Criteria (DVT): Active cancer=1, paralysis=1, bedridden=3, tenderness=1, swelling=1, calf swelling=1, pitting edema=1, collateral veins=1, previous DVT=1, alternative diagnosis=−2
≥2: likely DVT; <2: unlikely
≥2: likely DVT; <2: unlikely
Core Concepts
1. The Biopsychosocial Model
Engel (1977): illness results from interacting biological, psychological, and social factors. A diabetic patient's HbA1c depends on biology (insulin resistance), psychology (depression, self-efficacy), and social factors (food access, family support).
Engel (1977): illness results from interacting biological, psychological, and social factors. A diabetic patient's HbA1c depends on biology (insulin resistance), psychology (depression, self-efficacy), and social factors (food access, family support).
2. Continuity of Care
Ongoing relationship between patient and physician over time. Benefits: better chronic disease management, fewer hospitalizations, patient trust, reduced costs. Core principle distinguishing family medicine from episodic care.
Ongoing relationship between patient and physician over time. Benefits: better chronic disease management, fewer hospitalizations, patient trust, reduced costs. Core principle distinguishing family medicine from episodic care.
3. Preventive Medicine
Primary prevention: prevent disease onset (vaccination, lifestyle counseling). Secondary: early detection (screening). Tertiary: prevent complications (diabetic foot exams). USPSTF guidelines grade screenings A-D based on evidence.
Primary prevention: prevent disease onset (vaccination, lifestyle counseling). Secondary: early detection (screening). Tertiary: prevent complications (diabetic foot exams). USPSTF guidelines grade screenings A-D based on evidence.
4. Chronic Disease Management
Diabetes, hypertension, COPD, depression, heart failure — managed through protocols, care coordination, patient education, and regular monitoring. Patient-centered medical home (PCMH) model optimizes chronic care delivery.
Diabetes, hypertension, COPD, depression, heart failure — managed through protocols, care coordination, patient education, and regular monitoring. Patient-centered medical home (PCMH) model optimizes chronic care delivery.
5. The Clinical Method
History taking (70% of diagnosis) → Physical examination (15%) → Investigations (10%) → Diagnosis → Management. Open-ended questions, active listening, and differential diagnosis are core clinical skills.
History taking (70% of diagnosis) → Physical examination (15%) → Investigations (10%) → Diagnosis → Management. Open-ended questions, active listening, and differential diagnosis are core clinical skills.
Core Definitions
Primary Care: First-contact, continuous, comprehensive, and coordinated care. Delivered by family physicians, internists, pediatricians, and general practitioners. The backbone of health systems worldwide.
Motivational Interviewing: Collaborative counseling style to elicit behavior change. OARS: Open questions, Affirmations, Reflective listening, Summarizing. Effective for smoking cessation, weight loss, medication adherence.
Worked Examples
Example 1: CHAâ‚‚DSâ‚‚-VASc
75-year-old woman with AF, hypertension, diabetes:
Age≥75=2 + HTN=1 + DM=1 + Female=1 = 5 — high stroke risk. Needs anticoagulation (apixaban, rivaroxaban, or warfarin).
75-year-old woman with AF, hypertension, diabetes:
Age≥75=2 + HTN=1 + DM=1 + Female=1 = 5 — high stroke risk. Needs anticoagulation (apixaban, rivaroxaban, or warfarin).
Example 2: Well's Criteria for PE
Patient with dyspnea: unilateral leg swelling=1, HR>100=1, previous DVT=1, hemoptysis=1, cancer=1, alternative diagnosis less likely=1. Score=6 → likely PE. Proceed to CT pulmonary angiography.
Patient with dyspnea: unilateral leg swelling=1, HR>100=1, previous DVT=1, hemoptysis=1, cancer=1, alternative diagnosis less likely=1. Score=6 → likely PE. Proceed to CT pulmonary angiography.
Example 3: Diabetes Management
Type 2 diabetic, HbA1c 8.5% on metformin. Add SGLT2 inhibitor (empagliflozin) — cardiovascular and renal benefits. Lifestyle: diet, exercise, weight loss. Target HbA1c <7% for most adults.
Type 2 diabetic, HbA1c 8.5% on metformin. Add SGLT2 inhibitor (empagliflozin) — cardiovascular and renal benefits. Lifestyle: diet, exercise, weight loss. Target HbA1c <7% for most adults.
Practice Problems
Problem 1: Calculate BMI for a patient weighing 85 kg, height 1.70 m.
Answer: BMI = 85 / (1.70)² = 85/2.89 = 29.4 kg/m² — overweight (25-29.9)
Answer: BMI = 85 / (1.70)² = 85/2.89 = 29.4 kg/m² — overweight (25-29.9)
Problem 2: What is the difference between primary and secondary prevention?
Answer: Primary: prevent disease from occurring (vaccines, healthy lifestyle). Secondary: early detection and treatment of existing disease (mammography, colonoscopy, blood pressure screening).
Answer: Primary: prevent disease from occurring (vaccines, healthy lifestyle). Secondary: early detection and treatment of existing disease (mammography, colonoscopy, blood pressure screening).
Problem 3: A 68-year-old with AF has no risk factors. Calculate CHAâ‚‚DSâ‚‚-VASc.
Answer: Score = 0 (male, no risk factors). No anticoagulation needed. Annual reassessment recommended.
Answer: Score = 0 (male, no risk factors). No anticoagulation needed. Annual reassessment recommended.
Problem 4: What are the four pillars of evidence-based medicine?
Answer: Clinical expertise, best research evidence, patient values and preferences, and clinical context/circumstances.
Answer: Clinical expertise, best research evidence, patient values and preferences, and clinical context/circumstances.
Problem 5: Why is polypharmacy a concern in elderly patients?
Answer: Altered pharmacokinetics/ pharmacodynamics, increased drug-drug interactions, adverse drug reactions, falls, cognitive impairment, medication non-adherence, and prescribing cascades.
Answer: Altered pharmacokinetics/ pharmacodynamics, increased drug-drug interactions, adverse drug reactions, falls, cognitive impairment, medication non-adherence, and prescribing cascades.