Conn's Syndrome

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is Conn’s syndrome?

Conn’s syndrome is an endocrine disorder that occurs when aldosterone levels are too high. Aldosterone is a hormone that controls sodium and potassium levels in your body. When there is too much aldosterone, your body holds on to sodium and loses potassium below normal levels. This causes your body to retain too much water, which expands your blood volume. This, in turn, increases blood pressure. Other names for Conn’s syndrome include Conn’s disease, primary aldosteronism, and hyperaldosteronism.

The adrenal glands—small glands that sit above each kidney—make aldosterone and several other hormones. They are part of a complex system of glands and hormones called the endocrine system. In Conn’s syndrome, the adrenal glands are overactive. Sometimes, there is no clear reason for the overactivity. This is idiopathic Conn’s syndrome. In other cases, a benign tumor on one or both adrenal glands causes them to be overactive and make too much aldosterone. In rare cases, Conn’s syndrome is due to a cancerous tumor or an inherited condition.

Conn’s syndrome itself doesn’t really cause symptoms. Often, the first clue there is a problem is the development of high blood pressure, which is also usually asymptomatic. High blood pressure may show up on a regular screening or medical exam. Only about 1% of high blood pressure cases are due to Conn’s syndrome. When high blood pressure begins at a young age—before age 30, doctors may suspect a potential problem with aldosterone.

Sometimes, Conn’s syndrome causes low levels of potassium that can result in symptoms. This includes muscle cramps, weakness, fatigue and headache.

Conn’s syndrome is more common in women compared to men. It also most commonly occurs between ages 30 and 50.

Conn’s syndrome treatment depends on the underlying cause. Options may include surgery to remove the gland or medications to counteract the actions of aldosterone. Lifestyle changes are also an important part of treatment. This includes limiting sodium in your diet and exercising regularly.

Left untreated, Conn’s syndrome can lead to cardiovascular complications. This includes stroke, heart attack, and heart failure. It can also contribute to kidney disease and kidney failure. Seek immediate medical care (call 911) if you develop sudden symptoms, such as heart palpitations, chest pain, passing out, one-sided weakness in the face or extremities, or difficulty walking, talking, or understanding speech.

What are the symptoms of Conn’s syndrome?

Conn’s syndrome can cause high blood pressure and low potassium levels. While high blood pressure usually doesn’t cause symptoms, low potassium levels can in some cases.

Common symptoms of Conn’s syndrome

When Conn’s syndrome symptoms occur, they are typically a reflection of very low potassium levels (hypokalemia). Common symptoms may include:

  • Fatigue or headache
  • Vision problems

Serious symptoms that might indicate a life-threatening condition

In some cases, Conn’s syndrome can be life threatening due to prolonged or excessive high blood pressure or very low potassium levels. Having Conn’s syndrome increases the risk of cardiovascular complications more than just high blood pressure alone. This includes the risk of stroke, heart attack, and heart failure. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • Change in mental status or sudden behavior changes, such as confusion or disorientation
  • Chest pain, tightness or pressure, or rapid heart rate
  • Weakness, numbness, or paralysis or difficulty moving a body part

People with Conn’s syndrome often develop high blood pressure at an early age. In general, this means before age 30. Regular medical checkups can help identify early high blood pressure. There are other reasons for having high blood pressure at a young age. A thorough evaluation and lab testing can help your doctor find the root cause.

Conn’s disease affects about 1% of people with high blood pressure. When Conn’s syndrome is the cause, high blood pressure is often difficult to control. It can take three or more medicines to manage high blood pressure due to Conn’s disease. Typical high blood pressure medicines do not affect aldosterone. Correcting the aldosterone problem is the most effective way to bring blood pressure under control.

What causes Conn’s syndrome?

Conn’s syndrome occurs when the adrenal glands make too much aldosterone. There are several possible causes for this overproduction. In most cases, it is either the result of benign—or noncancerous—tumors or it is idiopathic. In idiopathic Conn’s syndrome, doctors are unable to find a cause for elevated aldosterone levels. Rarely, the cause of Conn’s syndrome is an inherited condition or a cancerous adrenal tumor.

What are the risk factors for Conn’s syndrome?

Anyone can develop Conn’s disease, but it is more common in people who fall into certain risk categories. Risk factors for Conn’s syndrome include:

  • Age: Conn’s syndrome is most common in people who are in their 30s and 40s.
  • Family history: Conn’s syndrome is more common in people with a family history of the condition or of high blood pressure or stroke before age 40.
  • Sex: Conn’s syndrome is more common in women than men.

Reducing your risk of Conn’s syndrome

Unfortunately, it is not possible to prevent or reduce the risk of developing Conn’s disease.

How is Conn’s disease treated?

Treatment for Conn’s disease depends on the underlying problem and whether or not both adrenal glands are involved. Doctors typically order an adrenal vein blood test before recommending treatment. This test measures the aldosterone coming from each adrenal gland.

If only one gland is the problem, surgery to remove it is the main treatment. The remaining adrenal gland is usually able to make enough aldosterone to maintain normal levels. In some cases, an aldosterone replacement is necessary. Removing the gland normalizes blood pressure and resolves symptoms in about 50 to 70% of cases.

When both glands are making too much aldosterone, medication is most often the treatment of choice. Removing one gland rarely leads to symptom control. Removing both glands will cause Addison’s disease—or adrenal insufficiency. So instead of surgery, doctors use medications called aldosterone-blocking drugs. They don’t lower the levels of aldosterone. Rather, they work to counteract the effects of aldosterone by promoting water loss—or diuresis—and helping your body hold on to potassium. Common aldosterone-blockers include spironolactone (Aldactone) and eplerenone (Inspra).

Lifestyle changes are an important part of managing Conn’s syndrome including:

  • Exercising regularly
  • Limiting alcohol
  • Lowering the amount of sodium in your diet

These strategies can help lower your blood pressure and help your medications work better.

What are the potential complications of Conn’s syndrome?

Complications from Conn’s syndrome are related to high blood pressure and low potassium levels. Neither high blood pressure nor low potassium typically cause symptoms. However, very low potassium and prolonged or excessive high blood pressure increases the risk of cardiovascular complications. In fact, having Conn’s syndrome increases the risk of these complications more than just having high blood pressure alone. Potential complications include stroke, heart attack, and heart failure. Kidney disease and kidney failure are also possible.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Oct 22
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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