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For further information, see CMDT Part 26-23: Primary Aldosteronism
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Essentials of Diagnosis
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Hypertension may be severe or drug-resistant
Hypokalemia (in minority of patients) may cause polyuria, polydipsia, muscle weakness
Low plasma renin; elevated plasma and urine aldosterone levels
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General Considerations
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Excessive aldosterone production
Cardiovascular events are more prevalent in patients with aldosteronism (35%) than in those with essential hypertension (11%)
May be caused by a unilateral aldosterone-producing adrenal cortical adenoma (Conn syndrome, 25%)
More commonly caused by adrenal cortical hyperplasia (75%)
Bilateral aldosteronism may be corticosteroid suppressible due to an autosomal-dominant genetic defect allowing ACTH stimulation of aldosterone production
Malignant ovarian tumors are rare cause of hyperaldosteronism
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Accounts for about 8% of cases of stage 2 (mild) hypertension and about 13% of cases of stage 3 (moderate) hypertension
Should also be suspected with early onset hypertension or stroke before age 50 years (or both)
Patients of all ages may be affected, but the peak incidence is between 30–60 years
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Hypertension is typically moderate but may be severe
Some patients have only diastolic hypertension, without other symptoms and signs
Edema (rare)
Muscle weakness (at times with paralysis simulating periodic paralysis), paresthesias with frank tetany, headache, polyuria, and polydipsia may be seen in patients with hypokalemia
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Differential Diagnosis
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Essential hypertension
Hypokalemic thyrotoxic periodic paralysis
Renal vascular hypertension (hypertension and hypokalemia, but plasma renin activity is high)
Hypokalemia due to other cause, eg, diuretics
Secondary hyperaldosteronism (dehydration, heart failure)
Congenital adrenal hyperplasia: 11beta-hydroxylase deficiency, 17alpha-hydroxylase deficiency
Cushing syndrome
Excessive real licorice ingestion
Syndrome of cortisol resistance
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Plasma potassium should be determined in hypertensive individuals; however, hypokalemia is present in only 37% of affected patients
An elevated serum bicarbonate (HCO3) concentration indicates metabolic alkalosis and is commonly present
Testing for primary aldosteronism should be considered for all hypertensive patients with any of the following:
Sustained hypertension above 150/100 mm Hg on 3 different days
Hypertension resistant to three conventional antihypertensive drugs, including a diuretic
Controlled blood pressure requiring four or more antihypertensive drugs
Hypokalemia, particularly when unrelated to diuretics
Personal or family history of early onset hypertension or CVA at age ≤ 40 years
First-degree relative with primary aldosteronism
Presence of an adrenal mass
Low plasma renin activity
Testing protocol