Plasma aldosterone level in a female case of pseudohyperaldosteronism (Liddle's syndrome)

A 22-yr-old female suffering from hypertension, hypokalemic alkalosis and suppressed plasma renin activity was studied. The plasma aldosterone concentration (PAC) ranged between subnormal and normal levels while the other adrenal mineralocorticoids were normal. Examinations through computed tomography and ultrasonography showed no abnormal findings. For differential diagnosis, dexamethasone, spironolactone and triamterene were administered. Triamterene alone corrected the abnormalities in this case, and the therapeutic effect was further enhanced by sodium restriction. Therefore, the present case is strongly suggested to be one of Liddle's syndrome, which is characterized by a primary defect in renal tubular sodium handling and can be corrected with triamterene. However, the patient in our study is different from the first reported case in which aldosterone secretion was estimated to be low. Analysis of the changes in PAC has shown that PAC is parallel with the level of plasma progesterone in accordance with the rhythm of the menstrual cycle and, in the follicular phase, PAC is rather low. It is concluded that the patient was suffering from Liddle's syndrome, and it is assumed that PAC is not always subnormal and, as same as in normal females, PAC may change in accordance with the rhythm of the menstrual cycle in a female case of Liddle's syndrome.