Causes of Secondary Hypertension - Differential Diagnosis and Screening Testing Common causes: • Renal parenchymal disease - Renal ultrasound, Tests to evaluate cause of renal disease • Renovascular disease - Renal Duplex Doppler ultrasound; MRA; abdominal CT, Bilateral selective renal intra-arterial angiography • Primary aldosteronism - Plasma aldosterone/renin ratio under standardized conditions (correction of hypokalemia and withdrawal of aldosterone antagonists for 4–6 wk). Oral sodium loading test (with 24-h urine aldosterone) or IV saline infusion test with plasma aldosterone at 4 h of infusion Adrenal CT scan, adrenal vein sampling. • Obstructive sleep apnea - Berlin Questionnaire; Epworth Sleepiness Score; overnight oximetry. Polysomnography • Drug or alcohol induced - Urinary drug screen (illicit drugs) Response to withdrawal of suspected agent Uncommon causes: • Pheochromocytoma/para ganglioma - 24-h urinary fractionated metanephrines or plasma metanephrines under standard conditions (supine position with indwelling IV cannula). CT or MRI scan of abdomen/pelvis • Cushing’s syndrome - Overnight 1-mg dexamethasone suppression test. 24-h urinary free cortisol excretion (preferably multiple); midnight salivary cortisol • Hypothyroidism • Hyperthyroidism • Aortic coarctation (undiagnosed or repaired) • Primary hyperparathyroidism • Congenital adrenal hyperplasia • Mineralocorticoid excess syndromes other than primary aldosteronism • Acromegaly #Secondary #Hypertension #Differential #Diagnosis #Causes #Screening #Workup #table
