Internal Medicine: Chronic Disease, Polypharmacy, and Renal Dosing
The Internal Medicine domain tests common adult medical problems in ambulatory and hospital settings: hypertension, diabetes, dyslipidemia, chronic kidney disease, COPD and asthma, anticoagulation, heart failure, and polypharmacy. The exam asks for guideline-concordant decisions that fit the patient's comorbidity and goals, not isolated numbers. Canadian guidelines-Hypertension Canada, Diabetes Canada, and the Canadian Cardiovascular Society-provide the expected thresholds and drug choices.
Core rules and concepts
- Treat the patient, not the number: confirm blood pressure with proper technique, assess adherence and white-coat effect, and set individualized targets.
- Diabetes: individualize HbA1c targets; use metformin early; add agents with proven cardiovascular or renal benefit (SGLT2 inhibitors, GLP-1 receptor agonists) when indicated.
- Chronic kidney disease: estimate GFR and urine albumin-to-creatinine ratio; adjust renally cleared drugs; use ACE inhibitors or ARBs when albuminuria is present and monitor potassium and creatinine.
- Polypharmacy: review indications, interactions, and anticholinergic burden; deprescribe when harms outweigh benefits.
- Anticoagulation: useCHA2DS2-VAScfor atrial fibrillation and assess bleeding risk; choose direct oral anticoagulants or warfarin based on renal function and valves.
Worked example
A 68-year-old woman with type 2 diabetes and hypertension has eGFR 42 mL/min/1.73 m² and urine albumin-to-creatinine ratio 45 mg/mmol. BP is 148/88. She takes metformin 1 g twice daily and ramipril 5 mg daily.
Reasoning: confirm BP and adherence. She has CKD with albuminuria. Continue the ACE inhibitor and titrate to the maximum tolerated dose, checking potassium and creatinine within 1–2 weeks. Add an SGLT2 inhibitor with proven renal benefit if not contraindicated. Review metformin: at eGFR 42, continue but do not increase; stop if eGFR falls below 30. Add a statin per Canadian Cardiovascular Society risk criteria. Set an individualized HbA1c target, often around 7.0–7.5% in older adults with comorbidity. Address diet, activity, and follow-up. The key feature is adjusting therapy for kidney function and albuminuria, not simply adding another antihypertensive.
Traps that cost marks
- Ignoring renal function when prescribing metformin, DOACs, or gabapentinoids.
- Failing to check potassium and creatinine after starting or titrating an ACE inhibitor or ARB.
- Treating isolated office hypertension without confirmation.
- Missing secondary causes: young onset, resistant hypertension, or hypokalemia.
- Continuing medications without a deprescribing review.