High Aldosterone Symptoms, Labs, and Next Steps

What High Aldosterone Does to Your Body

Aldosterone is a mineralocorticoid hormone made in the adrenal cortex. It tells the kidneys to retain sodium and excrete potassium. When aldosterone is chronically elevated, that simple instruction causes a cascade of problems.

Sodium Retention and Blood Pressure

Excess sodium retention expands plasma volume. The result is hypertension that often resists three or more antihypertensive drugs taken at optimal doses, which is the clinical definition of resistant hypertension. A 2020 meta-analysis in the Journal of the American Heart Association found primary aldosteronism in roughly 22% of patients with resistant hypertension, compared with 6% in the general hypertensive population [1]. Blood pressure readings frequently exceed 160/100 mmHg even on combination therapy.

Potassium Wasting and Muscle Symptoms

As aldosterone forces potassium out through the kidneys, serum potassium drops. Hypokalemia below 3.5 mEq/L causes:

• Muscle cramps and generalized weakness
• Fatigue that does not resolve with rest
• Constipation from smooth-muscle dysfunction
• Polyuria and polydipsia (the kidneys lose concentrating ability at low potassium)
• Palpitations and, in severe cases, ventricular ectopy

Roughly 40% of patients with confirmed primary aldosteronism are normokalemic at presentation, so a normal potassium does NOT rule out the diagnosis [2]. Waiting for hypokalemia before screening leads to missed cases.

Cardiac and Vascular Remodeling

High aldosterone has direct pro-fibrotic effects on the myocardium that are independent of blood pressure. A 2018 study in Hypertension (N=4,525) found patients with primary aldosteronism had a significantly higher rate of atrial fibrillation, non-fatal MI, and stroke compared with essential hypertension controls matched for blood pressure values [3]. Early diagnosis and treatment can reverse some of this damage.

Causes: Primary vs. Secondary Hyperaldosteronism

The clinical approach differs sharply depending on whether aldosterone is high because of autonomous adrenal overproduction or because another system is driving it.

Primary Aldosteronism

Primary aldosteronism (PA) means the adrenal glands are producing aldosterone independently of the renin-angiotensin-aldosterone system (RAAS). Renin is suppressed. The two main subtypes are:

• Aldosterone-producing adenoma (APA): A benign unilateral adrenal tumor, present in approximately 35-40% of PA cases. Conn syndrome refers specifically to an APA.
• Bilateral adrenal hyperplasia (BAH): Accounts for 60-65% of PA cases. Both adrenal glands overproduce aldosterone diffusely.

A less common cause is unilateral adrenal hyperplasia, and very rarely, familial hyperaldosteronism types I-IV (glucocorticoid-remediable aldosteronism), which are autosomal dominant and should be suspected when PA appears before age 20 or in multiple family members [4].

Secondary Hyperaldosteronism

In secondary hyperaldosteronism, renin is HIGH because something outside the adrenal glands is activating the RAAS. Aldosterone rises as a downstream response. Common causes include:

• Renal artery stenosis (typically atherosclerotic in older adults, fibromuscular dysplasia in younger women)
• Chronic kidney disease with reduced renal perfusion
• Heart failure with low cardiac output
• Cirrhosis with portal hypertension
• Diuretic overuse (thiazides, loop diuretics)
• Severe dehydration or sodium restriction

The ARR in secondary hyperaldosteronism is generally not elevated above 30 because both aldosterone and renin are high. The distinction matters because treatment targets the underlying cause, not the adrenal glands.

Which Patients Should Be Screened?

The Endocrine Society's 2016 Clinical Practice Guideline recommends screening in eight specific groups [5]:

1. Sustained hypertension above 150/100 mmHg on three separate measurements
2. Hypertension resistant to three conventional antihypertensive drugs
3. Hypertension controlled on four or more drugs
4. Hypertension with spontaneous or diuretic-induced hypokalemia
5. Hypertension with an adrenal incidentaloma
6. Hypertension in a first-degree relative of a patient with confirmed PA
7. Hypertension with sleep apnea
8. All patients with early-onset hypertension (onset before age 30, particularly if family history is present)

The HealthRX clinical team applies one additional internal rule: any patient presenting with hypertension plus two or more of the following, fatigue, muscle cramps, nocturia more than twice per night, and potassium below 3.8 mEq/L, gets an ARR on the first visit regardless of whether they formally meet the Endocrine Society criteria listed above. This lowers the threshold for catching PA in early or normokalemic presentations.

The Diagnostic Workup: Step by Step

Diagnosing primary aldosteronism is a three-stage process: screening, confirmation, and subtype differentiation.

Stage 1: Screening with the ARR

Draw morning plasma aldosterone concentration (PAC) and plasma renin activity (PRA) after the patient has been upright for at least two hours and seated for 15 minutes. An ARR above 30 ng/dL per ng/mL/hr with a PAC above 15 ng/dL is the most widely used positive screen [5].

Certain medications must be managed before testing:

• Hold for at least 4 weeks: Spironolactone, eplerenone, amiloride, triamterene, potassium-wasting diuretics, and licorice products.
• Hold for at least 2 weeks: ACE inhibitors, ARBs, beta-blockers, central alpha-2 agonists, NSAIDs.
• Acceptable to continue: Verapamil (slow-release), hydralazine, prazosin, doxazosin, and terazosin, which have minimal effect on the ARR.

Oral potassium supplementation to correct hypokalemia before the draw is acceptable and recommended by the Endocrine Society guideline, because hypokalemia itself suppresses aldosterone and can produce a false-negative screen.

Stage 2: Confirmatory Testing

A positive ARR requires biochemical confirmation with one of four tests. Saline infusion testing (2 liters of 0.9% NaCl over 4 hours with PAC measured at baseline and at 4 hours) is the most commonly used in outpatient settings. PA is confirmed when post-infusion PAC remains above 10 ng/dL [5]. The Endocrine Society guideline states: "Confirmatory testing is required in all patients with a positive screening test, with the exception of those with spontaneous hypokalemia, plasma renin below detection limits, and PAC greater than 20 ng/dL, in whom the diagnosis may be considered established." [5]

The oral sodium loading test (3 days of high-sodium diet with 24-hour urine aldosterone on day 3) is an alternative when intravenous infusion is impractical. Confirmed PA is a 24-hour urinary aldosterone above 12-14 mcg/day during sodium loading.

Stage 3: Subtype Differentiation

Once PA is biochemically confirmed, subtype testing determines whether the source is unilateral (surgery-eligible) or bilateral (medical management).

Adrenal CT scan is the first step. A clearly visible unilateral adenoma larger than 1 cm in a patient under 35 years of age is often sufficient to proceed directly to surgery. However, CT misclassifies subtype in up to 53% of PA cases compared with adrenal vein sampling (AVS) [6]. Small adenomas are missed, and apparent nodules on CT may be non-functioning incidentalomas.

Adrenal vein sampling (AVS) remains the gold standard for lateralization in most adults. AVS involves cannulating both adrenal veins and the inferior vena cava to measure aldosterone-to-cortisol ratios. A lateralization index (aldosterone/cortisol ratio on dominant side divided by the contralateral side) above 4:1 confirms unilateral excess [5]. AVS is performed at experienced centers, typically by interventional radiology, and has a technical success rate above 90% in centers doing more than 20 cases per year.

The 2016 SPARTACUS randomized trial (N=184) compared CT-directed therapy vs. AVS-directed therapy and found no significant difference in blood pressure outcomes at one year [7]. However, the SPARTACUS results have been interpreted cautiously, and most major centers still prefer AVS before recommending unilateral adrenalectomy in adults older than 35.

Treatment Options

Surgical Management: Adrenalectomy

Laparoscopic unilateral adrenalectomy is the preferred treatment for confirmed APA or unilateral adrenal hyperplasia. In published series, 30-72% of patients achieve complete biochemical cure (normal aldosterone and potassium without medications), and more than 90% achieve complete or partial clinical success (reduction in antihypertensive drug burden) [8]. Blood pressure normalization is more likely when hypertension duration is short, the patient is younger, body mass index is below 25 kg/m2, and fewer antihypertensive drugs were needed preoperatively.

Postoperative monitoring should include serum potassium and aldosterone at 1, 3, and 6 months. Contralateral adrenal suppression may cause transient hypoaldosteronism, requiring short-term fludrocortisone supplementation in some patients.

Medical Management: Mineralocorticoid Receptor Antagonists

Bilateral adrenal hyperplasia, or any PA case where surgery is declined or not possible, is managed with a mineralocorticoid receptor antagonist (MRA).

Spironolactone is first-line at 25-50 mg/day, titrated up to 100 mg/day over 4-8 weeks based on blood pressure and potassium response. The PATHWAY-2 trial (N=335) demonstrated that spironolactone was the most effective add-on drug for resistant hypertension, reducing systolic blood pressure by a mean of 8.7 mmHg more than placebo and more than bisoprolol or doxazosin [9]. Gynecomastia, breast tenderness, and menstrual irregularities limit tolerability in some patients, occurring in roughly 6-15% of men and women respectively on doses above 50 mg/day.

Eplerenone is a more selective MRA that avoids the sex-hormone side effects of spironolactone. Dosing starts at 50 mg twice daily and can be titrated to 100 mg twice daily. It is roughly half as potent as spironolactone per milligram and costs significantly more, but tolerability is better for patients who develop androgen-related adverse effects [10].

Both agents carry a risk of hyperkalemia, particularly in patients with chronic kidney disease or those on ACE inhibitors or ARBs. Serum potassium and creatinine should be checked 1 week and 4 weeks after initiating therapy and with every dose increase.

Amiloride (5-20 mg/day) is a potassium-sparing diuretic that blocks the epithelial sodium channel downstream of aldosterone. It is a reasonable alternative when MRAs are contraindicated, such as in pregnancy, where it is used off-label at lower doses under close monitoring.

Secondary Hyperaldosteronism: Treat the Root Cause

When the ARR is not elevated and renin is high, the treatment target is the underlying RAAS stimulus. Renal artery stenosis may warrant percutaneous transluminal angioplasty or stenting. Heart failure requires guideline-directed medical therapy including ACE inhibitors, ARBs, or sacubitril-valsartan. Diuretic-induced secondary hyperaldosteronism typically resolves when the offending diuretic is discontinued or the dose reduced.

Monitoring After Treatment

Whether the patient undergoes surgery or starts an MRA, structured follow-up prevents complications.

Post-Surgery Monitoring

• Serum potassium and creatinine: check at 1 day, 1 week, 1 month, and 3 months postoperatively.
• ARR: recheck at 3-6 months to confirm biochemical cure.
• Blood pressure medications: taper gradually starting 1-2 weeks after surgery as blood pressure allows; many patients can reduce from three or four drugs to one or zero.
• Annual reassessment for 5 years to detect rare contralateral disease progression.

Medical Therapy Monitoring

• Serum electrolytes and renal function: 1 week and 4 weeks after starting or adjusting MRA, then every 6 months when stable.
• Blood pressure: target below 130/80 mmHg per the 2017 ACC/AHA Guideline on the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults [11].
• Annual echocardiogram in patients with established left ventricular hypertrophy or prior atrial fibrillation to track structural regression.
• Repeat ARR at 3 months on therapy to verify biochemical control; a persistently elevated aldosterone on maximal MRA doses warrants repeat imaging to exclude a missed adenoma.

When to See a Specialist

Primary care providers can order the initial ARR and manage mild cases. Referral to an endocrinologist is appropriate when:

• The ARR is above 30 and PAC is above 15 ng/dL on two separate draws.
• Hypokalemia persists despite oral supplementation and MRA therapy.
• CT identifies a unilateral adrenal lesion.
• The patient is a surgical candidate and AVS is being considered.
• Familial hyperaldosteronism is suspected (onset before age 20 or strong family history).

Dr. William Young Jr., an endocrinologist at Mayo Clinic and lead author of multiple Endocrine Society guidelines on PA, has written: "Primary aldosteronism is underdiagnosed and undertreated. Most patients are managed for years as essential hypertension, accumulating cardiovascular and renal damage that targeted treatment would prevent." [5]