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Secondary Hypertension Workup Matrix

Screening thresholds, confirmatory tests, and high-yield board traps for refractory and early-onset hypertension.

ARR Ratio > 20 COMLEX / USMLE High-Yield
Conn Syndrome ARR Screen
> 20 Aldo/Renin Ratio + Aldo > 15
Triad: HTN + Hypokalemia + Metabolic Alkalosis (Note: 50% normokalemic!)
Pheochromocytoma Rule of 10s
10% Bilateral, Malignant, Extra-Adrenal
α-Blocker FIRST: Phenoxybenzamine 10–14d before β-blocker to avoid hypertensive crisis!
Renal Artery Stenosis (RAS) Auscultation & Imaging
Bruit + >30% Cr Bump on ACEi
Fibromuscular Dysplasia (FMD)

Young female (< 35 yo). Medial fibroplasia. Classic "string-of-beads" on renal/carotid angiography. Rx: Percutaneous angioplasty without stenting.

Atherosclerotic RAS

Older male (> 55 yo) with smoking and diffuse vascular disease. Flash pulmonary edema. Rx: Medical therapy (statins, anti-HTN); angioplasty + stenting if refractory.

Clinical Differentiation Matrix Board High-Yield
Confirmatory Pathways
Primary Hyperaldosteronism (Conn)

Autonomous adrenal cortex hypersecretion of aldosterone independent of renin.

Initial Screen: Plasma Aldosterone-to-Renin Ratio (ARR > 20).
Confirmatory: Saline suppression test (aldo fails to drop < 5 ng/dL).
Subtype Localization: Adrenal CT + Adrenal Vein Sampling (AVS).
Treatment: Unilateral adenoma → Laparoscopic adrenalectomy; Bilateral hyperplasia → Spironolactone / Eplerenone.
Pheochromocytoma

Chromaffin cell tumor of adrenal medulla secreting norepinephrine and epinephrine.

Classic Triad: Episodic Pounding Headache, Sweating (Diaphoresis), Tachycardia.
Initial Screen: Fractionated plasma free metanephrines.
Confirmatory: 24-hour urine metanephrines & vanillylmandelic acid (VMA).
Localization: Abdominal CT/MRI; 123I-MIBG scan for extra-adrenal paragangliomas.
Cushing Syndrome (Hypercortisolemia)

Central obesity, facial plethora (moon facies), buffalo hump, purple abdominal striae > 1 cm.

Initial Screening (Need 2): 24h urine free cortisol, late-night salivary cortisol, or 1 mg overnight dexamethasone test.
ACTH Level: < 5 pg/mL = Adrenal adenoma (ACTH-independent); > 20 pg/mL = ACTH-dependent.
High-Dose (8 mg) Dex: Suppresses pituitary adenoma (Cushing disease); fails to suppress ectopic ACTH (small cell lung ca).
Coarctation of the Aorta

Congenital juxtaductal aortic constriction. Turner syndrome (45,XO) and bicuspid aortic valve (70%).

Clinical Clue: Upper extremity hypertension with diminished/delayed femoral pulses (brachial-femoral delay).
Chest X-ray: Rib notching (inferior border 3rd–8th ribs via intercostals) + "Figure 3" sign.
Complications: Berry aneurysm rupture (subarachnoid hemorrhage), aortic dissection, endocarditis.