Wanpen Vongpatanasin, M.D. Answers Questions On: Conn’s Syndrome

Conn’s syndrome, also known as primary aldosteronism, is a condition that causes resistant high blood pressure. It is caused by excess production of a hormone called aldosterone. Aldosterone is secreted by the adrenal glands to stimulate excretion of potassium by the kidneys. When the adrenal glands are producing too much aldosterone, too much sodium is retained and blood volume is increased.

Conn’s syndrome may be caused by hyperplasia, or abnormal growth, of both adrenal glands or caused by tumor. However, it is often idiopathic – meaning that there is no particular reason for the condition.

Most Conn’s syndrome patients who do not know they have the condition have been doing everything they can think of to control their blood pressure, without success. They may be taking several blood pressure drugs, and every time they see a new physician for the problem, another drug gets added. So, living with undiagnosed Conn’s syndrome can be very frustrating for patients.

Conn’s syndrome used to be considered a rare disease, but it is now estimated to be present in as many as one out of every five people with complex hypertension. It usually causes no symptoms, though some patients may have fatigue, headaches, muscle weakness, and numbness.

For some years, physicians believed low blood potassium was a symptom of Conn’s syndrome. However, only about 40 percent of patients with Conn’s syndrome have low potassium. What we now look for is a history of low potassium when an individual is not taking diuretics.

Diagnosing Conn’s syndrome requires patience and multiple blood screenings. Many blood pressure medications interfere with the results of blood tests, so medications often must be changed out to ensure accurate results. However, once we are looking for Conn’s syndrome and doing the right tests at the right time, it's not hard to diagnose.

It depends on what is causing the condition. In about 30 percent of cases, the condition is caused by a tumor on one of the adrenal glands. However, the tumor is nearly always benign, so the diagnosis does not mean cancer. The tumor can be removed surgically, and the procedure is fairly straightforward, with few complications and just a short hospital stay.

If the condition is not caused by a tumor but rather is the result of a malfunction in both adrenal glands, we often prescribe a medication such as spironolactone or eplerenone to be used in combination with other blood pressure medications. It is very important to have an accurate diagnosis to make sure the dosage is correct.

Patients with Conn’s syndrome tend to have low serum potassium and need to take large quantities of a potassium supplement, but those who have had a benign tumor surgically removed to treat the condition may no longer require potassium.

Typically, 40 to 60 percent of people with Conn’s syndrome will experience big improvements in blood pressure management after diagnosis and treatment. For example, one of our patients with resistant hypertension wanted to do a triathlon, but his blood pressure was much too high—over 250—for him to compete safely. It turned out after several blood screenings that he had Conn’s syndrome. Once he got on the right drug regimen, he was able to complete triathlons successfully.

Yes. Studies show that people with Conn’s syndrome who receive appropriate treatment have better health outcomes and less thickening of heart muscle walls. Additional research is underway to better understand the causes and effects of the condition, which could help point the way to new ways to treat it.