Table 3 Laboratory examination of secondary hypertension
From: Resistant hypertension: consensus document from the Korean society of hypertension
Disease | Clinical history | Physical examination | Basic laboratory findings | Screening test | Confirmatory additional test |
|---|---|---|---|---|---|
Renal parenchymal disease | Urinary tract infection or obstruction, analgesic abuse, familial history of polycystic kidney disease | Abdominal mass (polycystic kidney disease) | Proteinuria, hematuria, pyuria, reduced GFR | Renal ultrasound | Further studies for kidney diseases |
Renal artery stenosis | Fibromuscular dysplasia, premature hypertension (female), atherosclerotic diseases, sudden onset or worsening of hypertension, resistant hypertension, recurrent pulmonary edema | Abdominal bruit | Rapid worsening of renal function [spontaneous or after ACE inhibitor or ARB treatment] | Kidney size difference > 1.5 cm, Duplex Doppler US, CT | MRI, digital subtraction angiography |
Primary aldosteronism | Muscle weakness, premature hypertension, familial history of premature stroke (< 40 years) | Arrhythmia (severe hypokalemia | Hypokalemia (spontaneously or after treatment by diuretics), incidental adrenal mass | Aldosterone-renin ratio (after correction of hypokalemia and excluding effect of ACE inhibitor or ARB) | Suppression test by saline infusion, fludrocortisone, and/or captopril); adrenal CT, adrenal vein sampling |
Pheochromocytoma | Paroxysmal hypertension, emergency visit by persistent hypertension with headache, sweat, and/or pallor, familial history | Café-au-lait lesion and neurofibromatosis neurofibroma | Incidental adrenal mass (extraadrenal mass in some cases) | Metanephrine and/or normetanephrine in 24-h urine | Abdominal and/or pelvic CT or MRI; radioisotope scan using meta-iodobenzylguanidine |
Cushing syndrome | Rapid weight gain, polyuria, polydipsia, psychiatric problems | Central obesity, moon face, buffalo hump, abdominal striae, hirsutism | Hyperglycemia | Free cortisol in 24-h urine | Dexamethasone suppression test |
Hypothyroidism | Dry skin; cold intolerance; constipation; hoarseness; weight gain | Delayed ankle reflex; periorbital puffiness; coarse skin; cold skin; slow movement; goiter | Â | High TSH; low or normal free T4 | Â |
Hyperthyroidism | Warm, moist skin; heat intolerance; nervousness; tremulousness; insomnia; weight loss; diarrhea; proximal muscle weakness | Lid lag; fine tremor of the outstretched hands; warm, moist skin | Â | Low TSH; high or normal free T4 and T3 | Radioactive iodine uptake and scan |
Hypercalcemia and primary hyperparathyroidism | Hypercalcemia | Nonspecific | Elevated serum calcium | Serum calcium | Serum parathyroid hormone |
Acromegaly | Acral features; enlarging shoe, glove, or hat size; headache; visual disturbances; diabetes mellitus | Acral features; large hands and feet; frontal bossing |  | Serum growth hormone ≥1 ng/mL during oral glucose loa | Elevated age- and sex-matched IGF-1 level; MRI scan of the pituitary |