Mineralocorticoid-induced kaliuresis in type-II pseudohypoaldosteronism

Area of Science:

• Nephrology
• Endocrinology
• Internal Medicine

Background:

• Type II pseudohypoaldosteronism is a rare disorder characterized by mineralocorticoid resistance.
• This condition often presents with hyperkalemia, metabolic acidosis, and hypertension.

Observation:

• A patient presented with hyperkalemia, normal glomerular filtration rate, normal aldosterone and urinary aldosterone levels, and low plasma renin activity.
• The patient also exhibited hyperchloremic metabolic acidosis and hypertension.
• Fractional excretion of potassium was reduced with sodium chloride loading but normal with sodium sulfate administration.

Findings:

• Thiazide diuretic therapy normalized serum potassium, bicarbonate levels, and blood pressure.
• The patient demonstrated significant natriuresis and kaliuresis in response to high-dose exogenous mineralocorticoid administration.
• The kaliuretic response to exogenous mineralocorticoid was notably pronounced, with only one prior report of similar magnitude.

Implications:

• This case highlights the diagnostic challenges of Type II pseudohypoaldosteronism.
• It underscores the efficacy of thiazide diuretics in managing the clinical manifestations of this disorder.
• The pronounced kaliuretic response suggests potential insights into mineralocorticoid receptor function or downstream signaling pathways.