- Primary aldosteronism is a condition where you make more of the hormone aldosterone than normal.
- Aldosterone helps balance the levels of salt and potassium in your body.
- Aldosterone helps control your blood pressure.
- Conn syndrome is one of the causes of primary aldosteronism.
- Depending on the cause, treatment may involve medicines or surgery (or both).
What is primary aldosteronism?
Primary aldosteronism is a condition where one or both of your adrenal glands makes too much of the hormone called aldosterone.
Aldosterone helps balance the levels of salt and potassium in your body. It also helps control blood pressure.
Primary aldosteronism leads to:
- hypertension (high blood pressure), which can be quite severe
- hypokalaemia (lower than normal potassium levels in your blood)
- an increased volume of blood in your body
Conn syndrome, also known as Conn's syndrome or Conn disease, is a common cause of primary hyperaldosteronism. It is when you have a non-cancerous tumour in one of your adrenal glands. The tumour, called an adenoma, makes aldosterone.
What are the symptoms of primary aldosteronism?
The most common sign is high blood pressure that is difficult to control, even with medicines. Some people also have symptoms such as:
- frequent urination (often needing to wee), including at night
- anxiety, irritability or depression
- trouble concentrating
- muscle weakness or cramps
- heart palpitations
What causes primary aldosteronism?
Conn syndrome is a common cause of primary hyperaldosteronism.
Primary aldosteronism can also happen when both of your adrenal glands become overactive and make too much aldosterone. This is called bilateral adrenal hyperplasia.
A few people have one of a group of inherited genetic conditions known as familial hyperaldosteronism.
Very rarely, primary aldosteronism is caused by a cancer in your adrenal gland.
Whatever the cause, excess aldosterone encourages your kidneys to keep salt in your body and not remove it in your urine (wee). If you keep salt in your body, you retain water as well. So, the amount of blood in your body increases. This causes high blood pressure.
When should I see my doctor?
You should see your doctor to have your blood pressure checked regularly. This is because it may change over time.
Ask your doctor to consider testing for primary aldosteronism if:
- you have high blood pressure that is not responding to treatment
- you have a family history of high blood pressure
- tests show low potassium levels in your blood
- you have high blood pressure and sleep apnoea
How is primary aldosteronism diagnosed?
Your doctor will ask about your symptoms and overall health and examine you. You may need tests and a referral to a specialist.
It is often difficult to diagnose primary aldosteronism. Doctors may suspect the condition if you have high blood pressure that does not respond to blood pressure medicines.
Hormone blood tests
Your doctor may order blood tests.
A test called an aldosterone-to-renin ratio can be used to check for primary aldosteronism. It checks your levels of:
- another hormone called renin
It's important that you follow the instructions you get before having this blood test. You will need to stop taking certain medicines for several weeks before the test.
Other tests for primary aldosteronism are:
- Blood tests to check your salt level, potassium levels and kidney function.
- A CT scan of your adrenal glands.
- Adrenal vein sampling — where blood samples are taken from the blood vessels coming from each of your adrenal glands.
- Genetic tests for familial hyperaldosteronism.
How is primary aldosteronism treated?
The treatment for primary aldosteronism will depend on what is causing your high aldosterone levels.
If both your adrenal glands are overactive, you will be prescribed a medicine to block the effect of too much aldosterone.
The most common medicine used is spironolactone, but there are other options. Talk with your doctor about the benefits and side effects of the different medicines.
Potassium supplements may also be recommended for some people.
If your condition is caused by an adrenal tumour, you will be referred to a surgeon. They can do an operation to remove your adrenal gland. This is known as an adrenalectomy.
If the tumour is small and not cancerous, you may be offered laparoscopic (keyhole) surgery. If the tumour is very large or may be cancerous, you are likely to have open surgery. Open surgery is done through a cut in your back, side or abdomen (tummy).
Surgery is done under a general anaesthetic.
You may need to take medicines as well as have surgery.
Can primary aldosteronism be prevented?
If you know that primary aldosteronism runs in your family, ask your doctor about screening and genetic testing.
If you have a gene associated with familial hyperaldosteronism, your doctor may suggest you restrict your salt intake. This can help delay the start of high blood pressure and other symptoms.
Complications of primary aldosteronism
Unless it is treated and controlled, primary aldosteronism can increase your risk of:
- heart disease, including heart attack
- heart failure
- heart arrhythmias, including atrial fibrillation
- kidney disease
Resources and support
Hormones Australia offers support and resources about the adrenal glands and conditions that affect them. They also publish a range of fact sheets in languages other than English, which are available here.
You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: October 2023