Diagnosis

Signs and Symptoms

• Mild hypertension
• Muscular weakness due to low potassium
• Polyuria and polydipsia
• Absence of edema
• Minimal retinal vascular changes

Laboratory Diagnosis

• Unprovoked hypokalemia is the hallmark of primary hypoaldosteronism
  • Monitoring of the potassium after salt loading with 10 g of sodium/day minimizes the false-negative normokalemic finding
  • Elevated 24-hour urine potassium excretions verifies renal potassium loss
• Low PRA following sodium restriction distinguishes primary hyperaldosteronism from secondary hyperaldosteronism due to renal disease and elevated renin secretions (high PRA)
• Elevated plasma or urinary aldosterone level indexed against urinary sodium excretion after potassium repletion and sodium loading taken together with a low PRA verifies the diagnosis

Tests to Delineate Adenoma and Hyperplasia

• With posture, both PRA and plasma aldosterone rise in patients with hyperplasia. Aldosterone does not rise in patients with an adenoma
• C-18 Cortisol methyl oxygenated metabolites are only elevated in patients with an adenoma
• Adrenal vein aldosterone-Cortisol ratio is unilaterally elevated in patients with an adenoma, bilaterally elevated in patients with hyperplasia

Adrenal Imaging

• Adrenal thin cut pre- and post-contrast CT
  • Adenoma: unilateral hypodense usually small, 0.5 to 2 cm
  • Hyperplasia bilateral nodular thickening

Treatment

• Adenoma: pre-treat with spironolactone to normalize potassium, then laparoscopic adrenalectomy
• Hyperplasia: medical management with spironolactone 50 to 200 mg/day (also calcium channel blockers are useful)
  • With asymmetric aldosterone secretion by sampling, unilateral adrenalectomy may be necessary if medical treatment fails

References

• Blumenfeld JD, Schlusse, Sealey JE, et al: Diagnosis and treatment of primary hyperaldosteronism. Ann Intern Med, 121:877-885, 1994.
• Blumenfeld JD, Vaughan ED Jr.: The adrenals. In: Campbell's Urology. 7th Ed. Philadelphia, Saunders, 1998, pp. 2915-2971.
• Manger WM, Gifford RW Jr.: Pheochromocytoma. A clinical review. In: Hypertension Pathophysiology, Diagnosis, and Management. Laragh JH, Brenner BM, eds. 1995, pp. 2225-2246.
• Orth DN: Cushing syndrome. N Eng J Med 332:791-795, 1995.
• Ulchaker JC, Goldfarb DA, Bravo EL, Novick AC: Successful outcomes in pheochromocytoma surgery in the modern era. J Urol 161:764-767, 1999. Vaughan ED Jr.: Adrenal surgery. F. F. Marshall, Ed. In: Textbook of Operative Surgery. Philadelphia, Saunders, 1996, p 220-230.
• Vaughan ED Jr., (ed): Diagnosis and treatments of adrenal disorders. World J Urol 17:1064, 1999.

Please log-in or register in order to submit comments.

Powered by AkoComment!