Liddle's syndrome, an uncommon form of hyporeninemic hypoaldosteronism: functional and histopathological studies.

Liddle's syndrome was diagnosed in a 72-year-old man who presented clinically with hypertension and muscle weakness. This disorder has been characterized by hyporeninemic hypoaldosteronism, hypertension, hypokalemia and enhanced erythrocyte sodium influx. Administration of spironolactone failed to correct the hypertension and electrolyte abnormality, which subsequently improved with triamterene therapy and a low salt diet. However, suppression of the renin-angiotensin-aldosterone system remained unchanged after this treatment. In addition, an atrophic juxtaglomerular apparatus and hypertensive lesions in the arterioles were confirmed by kidney biopsy after triamterene therapy. Therefore, a process of intrinsic hyperactive distal sodium reabsorption, probably affected by aldosterone-independent sodium transport into erythrocytes, appears to be important in the pathogenesis of this syndrome. Triamterene therapy, which usually is performed in patients with this disease, might not be the ultimate therapy in the future even if electrolyte abnormalities were to be improved temporarily.