What Is Primary Aldosteronism? | Endocrinology

Primary Aldosteronism

Overview of primary aldosteronism

Primary aldosteronism (also called Conn’s syndrome) is a rare condition caused by the overproduction of the hormone aldosterone that controls sodium and potassium in the blood. The condition is treated with medications and lifestyle changes to control blood pressure and in some cases surgery.

The adrenal glands are small triangular organs located in the upper part of the kidneys. They are part of the endocrine system, a group of glands that produce and secrete hormones that act on and regulate many systems throughout the body. Aldosterone is bent by the outer layer of the adrenal glands, the cortex. It is a hormone that plays an important role in maintaining blood volume, pressure, pH, and electrolyte balance. Its production is normally regulated by renin, a protein produced in the kidneys. Aldosterone increases when renin rises due to low blood pressure, decreased blood flow to the kidneys, or a sodium deficiency. When renin decreases, aldosterone also decreases.

In primary aldosteronism, an individual may produce excess aldosterone due to one or more benign adrenal tumours, due to overactivity of both glands called bilateral adrenal hyperplasia, or for unknown reasons (idiopathic). In rare cases, it is caused by a cancerous (malignant) adrenal tumour. Irrespective of the cause, aldosterone is produced despite low renin levels.

Increased aldosterone can lead to increased blood pH (alkalosis), hypertension, and high levels of sodium in the blood (hypernatremia). Primary aldosteronism can cause some nonspecific symptoms such as frequent urination, weakness, fatigue, and muscle cramps. A doctor may suspect primary aldosteronism in a person who has high blood pressure that is difficult to control, requires multiple blood pressure medications, and/or does not respond to standard treatments.

Secondary aldosteronism must be distinguished from primary aldosteronism. Secondary aldosteronism is caused by problems outside of the adrenal glands that cause the glands to release too much aldosterone. It is unlike primary aldosteronism because renin levels are high in secondary aldosteronism. Anything that increases renin levels, such as decreased blood flow to the kidneys, low blood pressure, or low levels of sodium in the urine, can cause secondary aldosteronism. The most important cause of secondary aldosteronism is the narrowing of the blood vessels supplying the kidney, which is called renal artery stenosis. Further causes include congestive heart failure, cirrhosis, kidney disease, and toxaemia of pregnancy.

Symptoms of primary aldosteronism

Primary aldosteronism generally causes high blood pressure with low potassium.

Other symptoms may include:

  • Excessive thirst.
  • Fatigue.
  • Frequent urination.
  • Headache.
  • Muscle cramps.
  • Visual disturbances.
  • Weakness or tingling.

Causes of primary aldosteronism

Primary aldosteronism is the result of the overproduction of aldosterone by the adrenal glands themselves. This hormone helps regulate the body’s water and sodium (salt) balance, blood volume, and blood pressure. In some cases, primary aldosteronism is the result of benign or non-cancerous tumours in one or both adrenal glands.

In rare cases, primary aldosteronism occurs due to an inherited disorder. In tremendously rare cases, cancerous tumours in one or both adrenal glands cause primary aldosteronism.

Diagnosis

To diagnose PA, your physician will ration the levels of aldosterone and renin in your blood. Renin is a protein produced by the kidneys that helps regulate blood pressure. In PA, renin levels are low and aldosterone levels are high. If PA is diagnosed, your doctor will get an adrenal imaging study (usually CT or MRI) to see if you may have a bilateral (on both sides) adrenal tumour or tumours.

Treatment of primary aldosteronism

Treatment for primary aldosteronism depends on the underlying cause. The basic goal is to get your aldosterone levels back to normal or to block the effect of high aldosterone to prevent complications.

Surgical removal of the gland

Surgical removal of the adrenal gland with the tumour (adrenalectomy) is usually recommended. Surgical removal may bring blood pressure, potassium and aldosterone levels back to normal. Your doctor will follow you closely after surgery and progressively adjust or eliminate your high blood pressure medications.

Risks of surgery include bleeding and infection. Adrenal hormone replacement isn’t necessary because the other adrenal gland can make enough of all the hormones your body needs.

Complications

Primary aldosteronism can main to high blood pressure and low potassium levels. These complications can lead to other problems.

Problems related to high blood pressure

Persistently high blood pressure can lead to heart and kidney problems, including:

  • Heart attack, heart failure, and other heart problems
  • Stroke
  • Kidney disease or kidney failure

People with primary aldosteronism have a higher than expected risk of cardiovascular problems compared to people with only high blood pressure.

Problems related to low potassium levels (hypokalemia)

Primary aldosteronism can cause low potassium levels. If your potassium levels are slightly low, you may not have any symptoms. Very low potassium levels can lead to:

  • Weakness
  • Irregular heartbeat
  • Muscle cramps
  • Excess thirst or urination
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