Hyperaldosteronism

Hyperaldosteronism is accompanied by elevation of blood pressure (115), and can be treated with an aldosterone antagonist, eg, spironolactone (117) which... 

Potassium-sparing by diuretic agents, particularly spironolactone, enhances the effectiveness of other diuretics because the secondary hyperaldosteronism is blocked. This class of diuretics decreases magnesium excretion, eg, amiloride can decrease renal excretion of potassium up to 80%. The most important and dangerous adverse effect of all potassium-sparing diuretics is hyperkalemia, which can be potentially fatal the incidence is about 0.5% (50). Therefore, blood potassium concentrations should be monitored carehiUy. 

The use of CA inhibitors as diuretics is limited by their propensity to cause metabolic acidosis and hypokalemia. Their use can be indicated in patients with metabolic alkalosis and secondary hyperaldosteronism resulting for example from aggressive use of loop diuretics. Furthermore, CA inhibitors are effective dtugs to produce a relatively alkaline urine for the treatment of cysteine and uric acid stones as well as for the accelerated excretion of salicylates. Perhaps the most common use of CA inhibitors is in the treatment of glaucoma. 

Hyperaldosteronism is a syndrome caused by excessive secretion of aldosterone. It is characterized by renal loss of potassium. Sodium reabsorption in the kidney is increased and accompanied by an increase in extracellular fluid. Clinically, an increased blood pressure (hypertension) is observed. Primary hyperaldosteronism is caused by aldosterone-producing, benign adrenal tumors (Conn s syndrome). Secondary hyperaldosteronism is caused by activation of the renin-angiotensin-aldosterone system. Various dtugs, in particular diuretics, cause or exaggerate secondary peadosteronism. 

Hyperkalemia is an excess of potassium in the blood. Clinical symptoms are muscle weakness and cardiac arrhythmias. It is caused by, e.g., hyperaldosteronism and angiotensin-converting enzyme (ACE) inhibitors. 

ACE inhibitors do not completely block aldosterone synthesis. Since this steroid hormone is a potent inducer of fibrosis in the heart, specific antagonists, such as spironolactone and eplerenone, have recently been very successfully used in clinical trials in addition to ACE inhibitors to treat congestive heart failure [5]. Formerly, these drugs have only been applied as potassium-saving diuretics in oedematous diseases, hypertension, and hypokalemia as well as in primary hyperaldosteronism. Possible side effects of aldosterone antagonists include hyperkalemia and, in case of spironolactone, which is less specific for the mineralocorticoid receptor than eplerenone, also antiandrogenic and progestational actions. 

The major mineralocorticoid, aldosterone, is secreted by cells of the zona glomerulosa. Primary hyperaldosteronism (Conn s syndrome) is associated with potassium depletion which is, in mm, responsible for the observed neuromuscular abnormalities seen in the disorder. These are similar to those seen in hypokalemic periodic paralysis (PP), with episodic and severe exacerbations of fixed muscle weakness. Muscle biopsy shows occasional muscle necrosis and vacuoles often these feamres are accompanied by mbular aggregates as in hypokalemic PP. All these changes can be attributed to the hypokalemia and not to excess aldosterone production per se. 

Diuretic pharmacotherapy (renal H+/chloride losses/2° hyperaldosteronism, renal ammoniagenesis)... 

Example, Bartter s or Gitelman s syndrome, Cushing s syndrome, hyperaldosteronism (1° or 2°), and Liddle s syndrome... 

Potassium-sparing diuretics are often coadministered with thiazide or loop diuretics in the treatment of edema and hypertension. In this way, edema fluid is lost to the urine while K+ ion balance is better maintained. The aldosterone antagonists are particularly useful in the treatment of primary hyperaldosteronism. 

Short-term preoperative treatment of patients with primary hyperaldosteronism. 

Long-term maintenance therapy for patients with bilateral micronodular or macronodular adrenal hyperplasia (idiopathic hyperaldosteronism). 

Diagnosis of primary hyperaldosteronism As initial diagnostic measure to provide presumptive evidence of primary hyperaldosteronism in patients on normal diets, as follows ... 

Long test-400 mg/day for 3 to 4 weeks. Correction of hypokalemia and hypertension provides presumptive evidence for diagnosis of primary hyperaldosteronism. 

Short test-400 mg/day for 4 days. If serum potassium increases but decreases when spironolactone is discontinued, consider a presumptive diagnosis of primary hyperaldosteronism. 

Maintenance therapy for hyperaldosteronism 100 to 400 mg/day in preparation for surgery. For patients unsuitable for surgery, employ the drug for long-term maintenance therapy at lowest possible dose. 

Edema Edema associated with CHF, hepatic cirrhosis, and the nephrotic syndrome steroid-induced edema, idiopathic edema, and edema due to secondary hyperaldosteronism. 

May be used alone or with other diuretics, either for additive diuretic effect or antikaliuretic (potassium-sparing) effect. It promotes increased diuresis in patients resistant or only partially responsive to other diuretics because of secondary hyperaldosteronism. 

Uses Hyperaldosteronism, ascites from CHF or cirrhosis Action Aldosterone... 

Aldosterone stimulates the rates of Na+ reabsorption and K+ secretion. This is relevant to the action of spironolactone, a diuretic that is a competitive inhibitor of aldosterone (discussed later). It is also pertinent because administration of diuretics can cause secondary hyperaldosteronism, which may exaggerate the potassium wasting that is a consequence of the increased delivery of Na+ and enhanced flow through distal convoluted tubules and collecting ducts. 

Primary hyperaldosteronism. Used as an aid in preparing patients with adrenal cortical tumors for surgery. 

Triamterene can be used in the treatment of congestive heart failure, cirrhosis, and the edema caused by secondary hyperaldosteronism. It is frequently used in combination with other diuretics except spironolactone. Amiloride, but not triamterene, possesses antihypertensive effects that can add to those of the thiazides. 

Contraindications Bilateral renal artery stenosis, hyperaldosteronism... 

Contraindications Bilateral renal artery stenosis, biliary cirrhosis or obstruction, primary hyperaldosteronism, severe hepatic insufficiency... 

When used for diagnosis of primary hyperaldosteronism, positive results are (long test) correction of hyperkalemia and hypertension (short test) serum potassium increases during administration, but falls upon discontinuation... 

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