• IMA sites
  • IMAJ services
  • IMA journals
  • Follow us
  • Alternate Text Alternate Text
עמוד בית
Sun, 15.12.24

Original Articles

IMAJ | volume

Journal 1, January 2002
pages: 17-20

Normokalemic Hyperaldosteronism in Patients with Resistant Hypertension

    Summary

    Background: Primary aldosteronism is a common cause of non-renal secondary hypertension. A correct diagnosis results in curing the hypertension or targeting appropriate pharmacotherapy. In patients with low renin resistant hypertension (after treatment with three or more different anti-hypertensive drugs the blood pressure remains above 140/90 mmHg), screening for aldosteronism is mandatory.

    Objectives: To demonstrate that normal blood levels of potassium in resistant hypertensive patients do not exclude the possible presence of hyperaldosteronism, and to suggest the use of the plasma aldosterone concentration (ng/dl)/plasma renin activity (ng/ml/hour) ratio in screening for hyperaldosteronism.

    Methods: Blood tests, suppression and stimulation tests (2 L normal saline IV/4 hours and 20 mg furosemide IV for 60 minutes in a standing position) were systematically performed in 20 low renin normokalemic resistant hypertensive patients. None had renal disorders, known endocrine abnormalities or heart failure. They did not receive anti-hypertensive drugs affecting PAC[1] or PRA[2]. Basal PRA and PAC were measured twice: PAC after saline infusion and PAC/PRA after stimulation.

    Results:. PAC/PRA above 50 was used to denote hyperaldosteronism. Serum K was 4 ± 0.07 mM/L, PAC 22.8 ± 1.8 ng/dl, PRA 0.13 ± 0.02 ng/ml/hour, PAC/PRA 190 ± 22 (above 100 in 17). After suppression PAC decreased from 25 ± 1.8 to 11 ± 1 ng/dl (normal <5 ng/dl). Stimulation did not affect PRA and PAC/PRA. Abdominal computed tomography scan revealed normal adrenal glands in 15 patients. Spironolactone (116 ± 60 mg/day) normalized blood pressure in all patients; it was used as a single therapy in 8, and in association with only one anti-hypertensive drug in the remaining 12 patients. In one patient the treatment was discontinued due to the presence of hyperkalemia.

    Conclusions: Low renin resistant hypertension associated with normokalemia may be due to hyperaldosteronism. Normal aldosterone levels in the basal condition do not exclude the possibility of hyperaldosteronism. Using a PAC/PRA ratio above 50 as a screening test can aid the physician in deciding when to perform dynamic tests, thus increasing the sensitivity of the diagnosis of hyperaldosteronism. CT scan is frequently normal. Targeted pharmacotherapy leads to a normalization of blood values.



    [1] PAC = plasma aldosterone concentration
    [2]
     PRA = plasma renin activity

    Legal Disclaimer: The information contained in this website is provided for informational purposes only, and should not be construed as legal or medical advice on any matter.
    The IMA is not responsible for and expressly disclaims liability for damages of any kind arising from the use of or reliance on information contained within the site.
    © All rights to information on this site are reserved and are the property of the Israeli Medical Association. Privacy policy

    2 Twin Towers, 35 Jabotinsky, POB 4292, Ramat Gan 5251108 Israel