If you’re doing everything to manage your blood pressure but can’t quite get it under control, primary aldosteronism might be the culprit.
This hard-to-pronounce hormonal imbalance often flies under the radar, camouflaged as ordinary hypertension.
Primary aldosteronism is a wolf in a slightly smaller wolf’s clothing. Its symptoms mimic those of high blood pressure, but its long-term consequences are much more severe.
The only clue to this serious condition might be a stubbornly high blood pressure that doesn’t respond to normal treatment. You might be acing your inhibitors, blocking your betas and best friends with salad, but if your blood pressure still feels like it’s plotting against you, it might be your adrenal glands working behind your back.
What is Primary Aldosteronism?
Primary aldosteronism is a condition where your adrenal glands start producing too much of a hormone called aldosterone.
Hormones are the chemical messengers of the body, secreted by organs to prompt changes in other organs. Often this works like a high-school gossip network, with messages passed on from organ to organ before finally reaching its intended target.
Aldosterone is produced by the adrenal glands to tell the kidneys to hold onto salt and jettison potassium. Salt retention causes water retention, which in turn increases blood pressure.
This is a constant and delicate adjustment made in response to all sorts of events happening inside and outside the body, like dehydration, sweating, or stress. Usually, it all happens in a beautifully co-ordinated chemical ballet.
But sometimes the adrenal glands start spurting huge amounts of aldosterone out of nowhere.
In around 30% of cases, one of the adrenal glands has a non-cancerous tumour that affects hormone production – this is called Conn’s syndrome. But in about 60% of cases, both adrenal glands produce too much aldosterone for an unknown reason.
Cumulative Cardiovascular Consequences
“High blood pressure is a really important risk factor for all sorts of illnesses. In face it’s the leading risk factor for death” observes Dr Jun Yang, a leading researcher of primary aldosteronism, member of the National Hypertension Taskforce, and member of the Endocrine Society Primary Aldosteronism Guideline Writing Group.
“People don’t really think about that. They think smoking, alcohol, diabetes, obesity – but actually, high blood pressure is the leading risk factor for death.”
High blood pressure is dangerous enough on its own, but primary aldosteronism makes a bad situation worse.
“People with primary aldosteronism have higher risk of heart failure, stroke, atrial fibrillation, and kidney failure than people with garden-variety hypertension” says Dr Yang. “The aldosterone is causing more damage above and beyond the high blood pressure itself.”
“People are familiar with the actions of aldosterone in the kidneys to help maintain salt and water balance. But the aldosterone receptor is also expressed in cardiovascular tissues and if you stimulate it, especially in the setting of excess salt, it leads to harmful tissue inflammation and fibrosis.”
A Dangerous Dearth of Diagnoses
“Traditionally it was thought to be rare, people haven’t paid much attention to it. It’s not prioritised in medical school. [But] in the past ten years there’s been more and more evidence to show it can affect people even with borderline [high] blood pressure.”
Many doctors are not aware of how common primary aldosteronism can be. “In a study where we advised and supported GPs to test for primary aldosteronism in people with recently diagnosed hypertension but not yet on drugs, we found that 1 in 7 had this condition” Dr Yang reports.
“Before we started [the study], we did an audit of the [GP] clinics, and less than 0.1% of hypertensive people had this diagnosis [of primary aldosteronism]. It’s one of those things where it’s right under our noses, but if you don’t order the test, you’ll miss it”
Her team is currently recruiting GP clinics who use Sonic Pathology and Best Practice software to participate in their CONSEP study. This study is trying to find out if software prompts can help increase screening for primary aldosteronism.
Subtle Signs and Symptoms
Symptoms of primary aldosteronism can be frustratingly vague.
The most telling sign is persistent high blood pressure that doesn’t seem to respond to medication, although even mildly elevated blood pressure can be caused by primary aldosteronism.
“Hypertension has always been called a silent killer, but primary aldosteronism is another silent killer, and you necessarily don’t feel anything.” says Dr Yang.
Like many other conditions and life generally, primary aldosteronism can cause fatigue, anxiety, and difficulty concentrating. Low potassium might cause muscle weakness or tiredness. Some people also report excessive thirst and frequent urination, as their body struggles to maintain salt and water balance, or a short temper and heavy snoring.
Pills and Procedures
Treatment for primary aldosteronism depends on personal preference and the underlying cause, but is usually pretty simple.
However, it depends on whether the condition affects one or both adrenal glands.
Most people have two adrenal glands that sit on top of the kidneys like little blobby hats. To find out what they’re up to, an adrenal CT scan and adrenal vein sampling (AVS) need to be performed. AVS involves a day procedure at a hospital where blood samples are taken directly from the glands and compared.
If one adrenal gland is affected by a tumour, keyhole surgery can remove the growth. This is usually enough to resolve the issue completely, while also keeping a gland to spare.
If both glands are affected, medication is a good alternative.
Spironolactone and eplerenone block the receptors that would usually register the presence of aldosterone, so organs can’t hear aldosterone’s messages. This not only lowers blood pressure by blocking aldosterone’s signals to the kidneys, but also prevents the longer-term damage wrought by excess aldosterone on other parts of the body. Amiloride can be prescribed to prevent the kidneys from retaining salt.
Pioneering Potential Pathways
“If your blood pressure is not well controlled, especially if you’re already taking tablets for it, there might be an underlying cause” emphasises Dr Yang.
As a leader in this area, she and her team have set up the Endocrine Hypertension Service for patients dealing with high blood pressure caused by hormonal issues.
Their REMASTER trial is currently recruiting people with high blood pressure and low renin (another signal for the early stages of primary aldosteronism).
And they’ve just received National Health and Medical Research Council funding to set up a Centre of Excellence, that promises to kickstart research into primary aldosteronism and spread the word about this surprisingly common condition.
