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hyperaldosteronism

Excessive secretion of aldosterone: Etiology: 1) primary hyperaldosteronism a) aldosterone-producing adrenal adenoma b) bilateral adrenal cortical hyperplasia - glucocorticoid-remediable hyperaldosteronism - 11-beta hydroxysteroid dehydrogenase deficiency c) criteria for diagnosis - diastolic hypertension without edema - hyposecretion of renin that fails to increase during volume depletion (upright posture, sodium depletion) - hypersecretion of aldosterone that does not suppress appropriately with volume expansion (salt loading) 2) secondary hyperaldosteronism a) aldosterone often higher than in primary hyperaldosteronism b) overproduction of renin - primary reninism - renin-producing juxtaglomerular cell tumor - renin-producing tumors may also arise from the ovary - Bartter's syndrome - decrease in renal blood flow - atherosclerosis - fibromuscular dysplasia - arteriolar nephrosclerosis c) increased circulating levels of renin substrate (angiotensin-1) in pregnancy d) licorice abuse Clinical manifestations: 1) mild to moderate diastolic hypertension 2) headaches 3) polyuria 4) muscle weakness 5) fatigue 6) edema may occur with secondary hyperaldosteronism Laboratory: 1) serum potassium: hypokalemia - hypokalemia inconsistently associated with primary hyperaldosteronism 2) serum sodium: hypernatremia 3) ABG may show metabolic alkalosis 4) urinalysis a) pH neutral to alkaline b) specific gravity low c) urine K+ in a patient with hypokalemia indicates renal K+ losing state d) urine Cl- often elevated e) after a 3 day high salt diet 1] 24 hour urine collection 2] measure Na+, K+, creatinine & aldosterone 3] aldosterone > 12 ug & urine Na+ > 200 meq/24 hr confirms diagnosis of hyperaldosteronism 5) plasma aldosterone elevated relative to plasma renin activity a) plasma aldosterone (ng/dL)/plasma renin activity (mg/mL/hr) 1] > 20 suggests primary hyperaldosteronism - > 100 may have 100% predictive value [4] 2] < 10 suggests secondary hyperaldosteronism b) selective venous sampling may help localize tumor c) discontinue spironolactone or eplerenone 6 weeks prior to testing [3] 6) autonomy of aldosterone secretion: a) salt loading or saline infusion fails to suppress plasma aldosterone b) captopril suppression test c) fludrocortisone suppression test 7) elevated plasma renin in patients on ACE inhibitor or ARB rules out hyperaldosteronism [3] 8) serum cortisol is normal 9) see ARUP consult [4] Special laboratory: - electrocardiogram: a) left ventricular hypertrophy b) signs of hypokalemia 1] prolongation of ST segment 2] U waves 3] T-wave inversions - adrenal vein sampling prior to adrenalectomy [3] Radiology: 1) CT scan may demonstrate adrenal mass (see adrenal incidentaloma) 2) MRI more sensitive than CT 3) iodocholesterol scan may be useful Management: 1) unilateral adrenal aldosterone-secreting adenoma - adrenalectomy (adrenal vein sampling prior to adrenalectomy) - aldosterone antagonis if not surgical candidate [3] 2) bilateral adrenal hyperplasia a) aldosterone antagonists 1] spironolactone 25-100 mg every 8 hours 2] eplerenone 3] triamterene 4] amiloride b) unilateral or bilateral adrenalectomy seldom cures hypertension 3) dietary sodium restriction 4) glucocorticoid-remediable hyperaldosteronism - dexamethasone has less mineralocorticoid activity than cortisol

Related

hypoaldosteronism; mineralocorticoid deficiency mineralocorticoid excess

Specific

Bartter syndrome primary hyperaldosteronism (Conn's syndrome)

General

adrenal gland disease syndrome

References

  1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 1965-68
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 227-29, 481-82
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 18, 19. American College of Physicians, Philadelphia 1998, 2012, 2018, 2022.
  4. Journal Watch 21(10):78, 2001 Gallay BJ et al, Screening for primary aldosteronism without discontinuing hypertensive medications: plasma aldosterone-renin ratio. Am J Kidney Dis 37:699, 2001 PMID: 11273868
  5. ARUP Consult: Aldosteronism The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/aldosteronism - Hyperaldosteronism Testing Algorithm https://arupconsult.com/algorithm/hyperaldosteronism-testing-algorithm
  6. Rossi GP. Diagnosis and treatment of primary aldosteronism. Rev Endocr Metab Disord. 2011 Mar;12(1):27-36 PMID: 21369868