[Primary hypoaldosteronism, pseudo-hypoaldosteronism and distal tubular acidosis]

Aldosterone deficiency is caused by various defects of aldosterone biosynthesis in the adrenal gland or hyporeninism. The most important symptoms are hyponatremia and hyperkalemia. These electrolyte disturbances are also found in pseudohypoaldosteronism. Pseudohypoaldosteronism type I is characterized by insensitivity of the distal nephron for aldosterone. Hyperabsorption of chloride in the distal nephron leads to pseudohypoaldosteronism type II, which is linked with hypertension, whereas blood pressure in the other mentioned disorders is decreased. Renal tubular acidosis, mainly type 4, with impaired production of ammonia due to hyperkalemia, is frequently observed in hypoaldosteronism and both types of pseudohypoaldosteronism as well. The therapeutic regimen is different: low doses of fludrocortisone in hypoaldosteronism, potassium restriction, sodium bicarbonate and loop diuretics in type I of pseudohypoaldosteronism, and sodium restriction and chloruretic diuretics (thiazide) in type II of pseudohypoaldosteronism. In some cases hyperkalemia requires the use of potassium-binding resins.