Secondary HTN & adrenal disorders

◆When to suspect secondary HTN

• •Onset before age 30 or after 55
• •Resistant HTN on ≥3 drugs at max doses
• •Severe HTN with end-organ damage
• •Spontaneous hypokalemia (think hyperaldosteronism)
• •Episodic HTN with headache/palpitations/sweating (think pheo)
• •Abdominal bruit (think renovascular)
• •Differential arm/leg BP (think coarctation)

◆Primary hyperaldosteronism (Conn)

• •HTN + hypoK + metabolic alkalosis (some patients are normokalemic)
• •Aldosterone:renin ratio (ARR) >20–30 → screen positive
• •Confirm: saline suppression test (failure to suppress aldosterone)
• •Adrenal CT → adrenal vein sampling to lateralize
• •Unilateral adenoma → adrenalectomy; bilateral hyperplasia → spironolactone or eplerenone

◆Cushing syndrome

• •Central obesity, moon facies, buffalo hump, purple striae, easy bruising, proximal weakness, hyperglycemia, HTN
• •Screen: 24-h urine cortisol, late-night salivary cortisol, OR 1-mg overnight dexamethasone suppression
• •If positive → ACTH level. Low ACTH = adrenal (CT adrenals). High ACTH = pituitary (MRI) or ectopic (chest/CT)
• •High-dose dexamethasone suppression: pituitary tumor suppresses, ectopic does not
• •Treatment: surgical resection of tumor; ketoconazole / metyrapone bridge

◆Pheochromocytoma

• •Episodic HTN + headache + palpitations + diaphoresis (the 5 P's: pressure, pain, palpitations, perspiration, pallor)
• •Screen: plasma free metanephrines (most sensitive) OR 24-h urine metanephrines
• •Confirm + localize: CT/MRI adrenals; MIBG scan if extra-adrenal suspected
• •Pre-op: α-blockade (phenoxybenzamine) FIRST, then β-blocker — never reverse order
• •Surgical resection curative; check for MEN-2 (medullary thyroid CA + parathyroid)

◆Renovascular HTN

• •Atherosclerotic (older, smoking, CVD risk) vs Fibromuscular dysplasia (young women, 'string of beads')
• •Clues: abdominal bruit, asymmetric kidneys, AKI on ACE-I (bilateral disease)
• •Screen: renal artery Doppler, CTA, or MRA
• •Treat: ACE-I/ARB if unilateral disease (NEVER bilateral); angioplasty for FMD; medical management for atherosclerotic (revasc doesn't improve outcomes in most)

◆Adrenal insufficiency

• •Primary (Addison): adrenal destruction → ↑ ACTH → hyperpigmentation, hypoglycemia, hyperK, hypoNa, hypotension
• •Secondary: pituitary failure → normal K (mineralocorticoid intact), no hyperpigmentation
• •Test: AM cortisol < 3 = deficient; > 15 = excludes; intermediate → cosyntropin stim test
• •Acute (Addisonian crisis): hypotension + AMS + electrolyte chaos → STRESS-dose hydrocortisone 100 mg IV, fluids
• •Chronic: replace hydrocortisone (or prednisone) + fludrocortisone (if primary)

◆Congenital adrenal hyperplasia

• •21-hydroxylase deficiency (most common): salt-wasting crisis + ambiguous genitalia in girls, virilization; ↑ 17-OH progesterone
• •11β-hydroxylase deficiency: HTN + virilization (excess 11-deoxycortisol has mineralocorticoid activity)
• •17α-hydroxylase deficiency: HTN + hypoK + no virilization + lack of secondary sex characteristics
• •Treat: hydrocortisone (+ fludrocortisone for salt-wasting); surgical correction of genitalia

Secondary HTN pattern recognition