Aldosterone helps control blood pressure by clinging to salt and losing potassium from the blood. Increasing salt increases blood pressure.
Hyperaldosteronism is a condition in which the adrenal glands produce too much aldosterone, which causes hypertension (high blood pressure) and low levels of potassium in the blood.
Primary hyperaldosteronism may be caused by hyperactivity in an adrenal gland (unilateral disease) or both (bilateral disease).
Unilateral disease is usually caused by an aldosterone-producing adenoma (benign tumor) and less commonly by adrenal cancer or hyperplasia (when the entire gland is overactive). Bilateral disease is usually caused by bilateral hyperplasia (when both glands are overactive).
There are rare genetic syndromes, such as familial hyperaldosteronism type I and II, which can cause both glands to be hyperactive.
- Primary hyperaldosteronism ( crohn syndrome ).
- Adrenal adenoma in CT.
Bilateral disease is usually caused by bilateral hyperplasia (when both glands are overactive). There are rare genetic syndromes, such as familial hyperaldosteronism type I and II, which can cause both glands to be hyperactive.
Signs and symptoms
High blood pressure is often the only sign of hyperaldosteronism. Hypertension is usually difficult to control and patients often take 4 or more medications for blood pressure. Hypertension can cause headaches, blurred vision and dizziness.
While patients with hyperaldosteronism may have normal potassium levels, many patients may have low potassium levels. The hypokalemia (low potassium) can cause symptoms such as fatigue, numbness, increased urination, increased thirst, muscle cramps and muscle weakness.
Primary hyperaldosteronism is diagnosed by measuring the blood levels of aldosterone and renin (a hormone produced by the kidney).
To better measure these hormones, blood samples must be taken in the morning. In primary hyperaldosteronism, the level of aldosterone will be high, while the renin will be low or undetectable.
The potassium level can be low or normal. If these tests are positive, patients may have another test to confirm the diagnosis. These tests try to reduce the amount of aldosterone produced by administering a medication or by administering extra salt through the diet or an intravenous fluid.
If the aldosterone level is high and the renin level is low after these tests, the diagnosis is confirmed. Some medications, especially blood pressure medications, can interfere with these tests.
Your doctor will review your medications and decide if it is necessary to suspend them for 4 to 6 weeks before the test.
In general, patients with a history of hypertension that is difficult to control should be screened for hyperaldosteronism.
This blood test is a screening test, which means that it is done if hyperaldosteronism is suspected but has not yet been diagnosed. A high proportion of PAC to PRA suggests primary hyperaldosteronism, but additional tests may be needed to confirm the diagnosis.
Captopril suppression test:
This blood test measures the body’s response to captopril, a medication used to treat high blood pressure. The results of this test can confirm whether a person has primary hyperaldosteronism.
24-hour urinary excretion of the aldosterone test:
Patients consume a diet high in salt for five days and then undergo urine tests for a period of 24 hours. If the level of aldosterone in the urine is high, these results can confirm that a patient has primary hyperaldosteronism.
Saline suppression test:
In this test, the patient receives a salt solution intravenously. Then, a blood test measures the patient’s aldosterone and renin levels. Primary hyperaldosteronism can be confirmed if the level of aldosterone in the blood remains high and the renin is low after this salt loading.
For patients with proven primary hyperaldosteronism, the next step is to determine whether it is a unilateral or bilateral disease. This is critical because the treatment for each one is different.
A computed tomography (CT or CAT) or magnetic resonance imaging (MRI) will be done to see if there is a tumor in any of the adrenal glands.
If the patient is under 40 years old and there is a tumor in a single adrenal gland (especially if it measures between 1 and 2 cm), then the patient can go directly to the treatment.
If the patient is older than 40 years and / or no tumor is observed or there are tumors in both adrenal glands, a special test called selective venous sampling will be performed.
In this test, a surgeon or radiologist draws blood directly from the veins that drain both adrenal glands to determine if one or both are producing too much hormone.
The significantly higher levels of hormones on one side only ensure the diagnosis of unilateral disease. Selective venous sampling is usually performed as an outpatient procedure
The treatment for hyperaldosteronism depends on the underlying cause. In patients with a single benign tumor (adenoma), surgical removal (adrenalectomy) is curative.
This operation is usually performed laparoscopically , through several very small incisions. After a successful adrenalectomy, approximately 95% of patients notice a significant improvement in their hypertension .
Of this 95%, one third is cured of high blood pressure and the rest takes fewer medications or lower doses. For patients with bilateral hyperplasia, the best treatment is a drug called aldosterone antagonist (spironolactone, eplerenone) that blocks the effect of aldosterone.
In addition, patients are kept on a low-salt diet.
Without proper treatment, patients with hyperaldosteronism often suffer from poorly controlled high blood pressure and have an increased risk of heart attacks, heart failure, stroke, kidney failure and premature death.
However, with proper treatment, this disease is treatable and has an excellent prognosis. Patients with difficult-to-control or long-term hypertension should be screened for primary hyperaldosteronism.