Aldosteronism, Primary

– A hypertensive disorder resulting from excess production of aldosterone by the adrenal gland.

Causes and Incidence

Most cases are caused by an adenoma of the adrenal gland. Other causes are adrenal nodular hyperplasia and adrenal carcinoma. Only 0.5% to 2% of those with hypertension are affected. The condition is three times more likely to affect women; the typical age ranges from 30 to 50 years.

Disease Process

Excess production of aldosterone leads to hypernatremia, hypervolemia, and hypokalemic alkalosis. Mild to severe arterial hypertension occurs because of the increased volume and arteriolar sodium levels. Hypokalemia results from increased renal excretion of potassium, and metabolic alkalosis occurs because of an increase in hydrogen ion secretion. Over time this leads to transient paralysis and tetany.

Symptoms

In many cases the only manifestation is a mild to moderate hypertension. Other signs and symptoms include episodic weakness, fatigue, paresthesia, polyuria, polydipsia, and nocturia. Glycosuria, hyperglycemia, and personality disturbances are occasionally manifested.

Potential Complications Marked alkalosis with transient paralysis, tetany, and positive Chvostek’s and Trousseau’s signs.

Diagnostic Tests

Plasma renin activity – Decreased (measured after restricted sodium/diuretic therapy).

Aldosterone levels – Increased (measured after sodium loading).

Blood chemistry – Normal/increased sodium, decreased potassium.

Computed tomography scan – To detect presence of adenoma.

Blood pressure – Elevated.

Edema – Absent.

Treatments

Surgery – Adrenalectomy.

Drugs – Spironolactone (Aldactone).

General – Low-sodium diet; instruction about medication, diet, and surgery.

_____________________________________