Primary Aldosteronism (Conn's Syndrome): This condition is characterized by the excessive production of aldosterone, leading to sodium retention, water retention, and potassium excretion, resulting in hyponatremia and hypokalemia. It is a common cause of resistant hypertension and can explain the persistent electrolyte imbalances.

Heart Failure: In heart failure, decreased cardiac output leads to increased aldosterone levels, causing sodium and water retention and potassium loss. This can result in hyponatremia and hypokalemia.
Nephrotic Syndrome: The loss of albumin in the urine can lead to hypoalbuminemia, which causes a decrease in oncotic pressure, resulting in edema and potentially hyponatremia due to dilutional effects. Hypokalemia can occur due to increased urinary excretion of potassium.
Diuretic Abuse: The use of diuretics, especially thiazides and loop diuretics, can lead to loss of potassium and sodium in the urine, resulting in hypokalemia and hyponatremia if not properly managed.

Adrenal Insufficiency (Addison's Disease): Although less common, adrenal insufficiency can cause hyponatremia and hyperkalemia due to the lack of aldosterone. However, in some cases, especially with primary adrenal insufficiency, hypokalemia can occur due to the mineralocorticoid effect of cortisol when the patient is under stress or receiving glucocorticoid replacement.
Pituitary or Hypothalamic Disease (SIADH - Syndrome of Inappropriate Antidiuretic Hormone Secretion): SIADH can cause hyponatremia due to excessive water retention. While hypokalemia is not a hallmark, it can occur due to the secondary effects of hyponatremia treatment or other associated conditions.

Liddle's Syndrome: A rare genetic disorder characterized by excessive sodium absorption and potassium secretion in the distal nephron, leading to hypertension, hypokalemia, and metabolic alkalosis. Hyponatremia might not be a direct consequence but can occur in the context of volume expansion.
Bartter Syndrome and Gitelman Syndrome: These are rare genetic disorders affecting the kidneys' ability to reabsorb potassium, sodium, and chloride. They typically present with hypokalemia, alkalosis, and normal to low blood pressure. Hyponatremia can occur due to the secondary effects of volume depletion or other associated electrolyte imbalances.
Cushing's Syndrome: Excess cortisol can cause hypertension, hypokalemia, and sometimes hyponatremia, especially if there is associated heart failure or renal effects leading to water and sodium retention.