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.