Internal Medicine (Subspecialties and Geriatrics)
Internal medicine (内科) is the largest block of the exam. Questions reward guideline-consistent initial management and recognition of presentations that must not be missed, especially in older adults where classic signs are blunted.
Core rules
- Heart failure with reduced ejection fraction: four prognostic pillars - ARNI/ACE inhibitor, beta-blocker, mineralocorticoid receptor antagonist, SGLT2 inhibitor - started early; diuretics relieve congestion but do not change prognosis. Watch for hyperkalaemia and renal function at each step.
- Hypertension (JSH): office ≥140/90, home ≥135/85; target <130/80 in most adults, individualised in frail elderly. Screen for secondary causes when young, resistant, or accompanied by hypokalaemia (primary aldosteronism), bruits (renovascular), or resistant snoring (sleep apnoea).
- Diabetes: SGLT2 inhibitors and GLP-1 receptor agonists preferred with atherosclerotic disease, heart failure, or CKD; avoid metformin when eGFR <30; sulfonylureas and insulin carry hypoglycaemia risk in the elderly.
- AKI (KDIGO): differentiate prerenal (low fractional excretion of sodium, high BUN/creatinine ratio, responds to fluid) from acute tubular necrosis (muddy brown casts).
- Geriatrics: frailty, polypharmacy, deprescribing of benzodiazepines, anticholinergics, and long-acting sulfonylureas; advance care planning.
Worked example
An 82-year-old woman on hydrochlorothiazide presents with confusion: Na 118, plasma osmolality 250, urine osmolality 480, urine Na 60, clinically euvolemic. Reasoning: hypotonic hyponatraemia with concentrated urine and high urinary sodium in a euvolemic patient suggests thiazide-associated SIADH; check TSH and cortisol and review SSRIs and carbamazepine. Correct by ≤8 mmol/L/day to avoid osmotic demyelination; stop the thiazide and fluid-restrict; reserve hypertonic saline for seizures.
Traps
- Treating asymptomatic bacteriuria in older adults.
- Labelling delirium as dementia.
- Forgetting that a normal anion gap acidosis points to gastrointestinal or renal tubular bicarbonate loss, not ketosis.