hypertension

HTN Canada 2025: diagnose at >=130/80 mmHg (method-specific thresholds apply). Lifestyle first for low-to-moderate risk; treat >=140/90 (all) or >=130 systolic if high CVD risk. Start with single-pill combination (RASi + thiazide or CCB), escalate stepwise, add spironolactone as best 4th-line agent. Secondary causes warrant workup when resistant or clinically atypical.

diagnosis

Mean AOBP, ABPM, or HBPM >=130/80 mmHg
AOBP preferred in-office (no observer, automated series of 3+)
Confirm on >=2 readings across >=2 visits before labelling
If office BP elevated with normal out-of-office readings → white coat hypertension (confirm with ABPM or HBPM)
If office BP normal with elevated out-of-office → masked hypertension (treat as HTN)

treatment thresholds and targets

population	treat if	target
general	>=140/90	<130/80
high CVD risk (CAD, PVD, stroke/TIA, HF, DM, CKD eGFR <60 or ACR >=3, FRS >=20%, age >=75)	SBP >=130	<120 (SPRINT-eligible)
IgA nephropathy	—	<120/70
ADPKD	—	<110/75 if <50 yr; <120/80 if >=50 yr
pregnancy	—	DBP <85
post-tPA stroke	—	<180/105 for 24 h
acute stroke (no tPA)	—	do not treat unless >220/120

lifestyle and nonpharmacologic therapy

First-line for newly diagnosed low-to-moderate risk — most patients crossing the lowered 130/80 threshold
Sodium restriction <2 g/d, DASH diet, aerobic exercise >=150 min/wk, alcohol reduction, weight loss if BMI >25
Reassess in 3–6 months; escalate to pharmacotherapy if targets not met

stepwise pharmacotherapy

Single-pill combination (SPC): RASi + thiazide or RASi + DHP CCB — e.g. irbesartan/HCTZ 150/12.5 mg or perindopril/amlodipine
Titrate SPC to full dose
Add third agent (CCB if not in SPC, or thiazide if not in SPC)
Add spironolactone 12.5-25 mg — best 4th-line per PATHWAY-2 (2015); amiloride non-inferior alternative per Lee, JAMA. 2025. Avoid if eGFR <30 or K⁺ >4.5. At this stage, initiate secondary HTN workup

secondary hypertension workup

Screen when: onset <30 or >55 yr, resistant HTN (>=3 agents at optimal doses including a diuretic), unprovoked hypokalaemia, adrenal incidentaloma, paroxysmal symptoms, abdominal bruit, or rapid eGFR decline on RASi.

renovascular hypertension

Atherosclerotic RAS: older patients, diffuse atherosclerosis. Screen with CTA/MRA/Doppler. Medical therapy first; angioplasty +/- stent reserved for refractory HTN, flash pulmonary oedema, or progressive CKD
Fibromuscular dysplasia: young women, “string of beads” on angiography. Angioplasty without stent. Screen vasculature head to pelvis (multivessel involvement common)
Clue: Cr rise >=30% after ACEi/ARB initiation

primary aldosteronism

Morning aldosterone-to-renin ratio (ARR) — hold MRAs >4 wk, ACEi/ARBs/diuretics/CCBs >2 wk before testing; repeat off OCP if borderline
Confirmatory testing (salt loading or fludrocortisone suppression) → adrenal CT → adrenal vein sampling before any unilateral adrenalectomy
Bilateral disease (most common) → spironolactone or eplerenone

phaeochromocytoma

24 h urine fractionated metanephrines + catecholamines, or plasma free metanephrines
Alpha-blockade first (phenoxybenzamine or doxazosin) — titrate over 10-14 days before surgery
Beta-blockers only after adequate alpha-blockade (unopposed alpha stimulation → hypertensive crisis)

beta-blockers before alpha-blockade

Never start beta-blockers before alpha-blockade in suspected phaeochromocytoma — loss of beta-mediated vasodilatation with unopposed alpha stimulation precipitates hypertensive crisis.

hypertensive emergencies

Acute BP elevation with end-organ damage (encephalopathy, AKI, aortic dissection, pulmonary oedema, eclampsia, acute coronary syndrome).

general approach

Reduce BP 20-25% over 1-2 h, then toward 160/100 over 2-6 h
IV titratable agents (labetalol, nicardipine, nitroprusside, nitroglycerin)
Avoid precipitous drops — risk of watershed ischaemia

specific scenarios

scenario	management
aortic dissection	IV beta-blocker first (target HR <60), then IV vasodilator (nicardipine or nitroprusside)
cocaine/sympathomimetic	phentolamine + benzodiazepines; labetalol acceptable alternative
scleroderma renal crisis	ACEi (captopril PO or IV enalaprilat) — do not withhold even if creatinine rising
eclampsia/pre-eclampsia	IV labetalol or hydralazine; magnesium for seizure prophylaxis
acute pulmonary oedema	IV nitroglycerin + furosemide

scleroderma renal crisis

ACEi is the treatment of choice — discontinuing or withholding ACEi worsens outcomes. Do not hold for rising creatinine. Corticosteroid use (>=15 mg/d prednisone) is the most common precipitant.

traps

Diagnosing HTN on a single office reading — confirm with AOBP series, ABPM, or HBPM before labelling and treating
Monotherapy uptitration before combination — dual low-dose combination is more effective with fewer side effects; HTN Canada 2025 favours SPC first
Forgetting to screen for secondary causes at step 4 — resistant HTN mandates workup (primary aldosteronism is underdiagnosed — prevalence ~10% of resistant HTN)
Holding ACEi in scleroderma renal crisis — reflex to stop ACEi for rising Cr is wrong here; ACEi is the treatment
Beta-blocker before alpha-blockade in phaeochromocytoma — precipitates hypertensive crisis