Primary aldosteronism: an overlooked factor for hypertension?
Little is known about a syndrome called primary aldosteronism (PA), characterised by the overproduction of the hormone aldosterone by one or both adrenal glands (small structures that sit atop the kidneys). Even though the syndrome shows up in people with either mild, moderate, or severe high blood pressure, or hypertension — and even in those with normal blood pressure — less than 1% of cases are diagnosed and treated accordingly. PA is thought to be an overlooked critical factor behind hypertension.
[Aldosterone increases blood pressure by transporting sodium and water into/out of the bloodstream, increasing blood volume; aldosterone also lowers potassium to maintain optimal blood pressure. Excess aldosterone is toxic to the heart, blood vessels, kidneys, and other organs.]
Compared to a standard hypertension diagnosis, those with PA have greater risk of kidney disease, heart failure, coronary artery disease, and stroke. Unfortunately, as clinicians often overlook these symptoms, patients are prescribed blood pressure medications that do little to treat the root cause of their condition and miss out on effective treatments that include low-salt diets and targeted drugs.
Some experts have warned of a looming public health crisis – one that demands widespread changes in hypertension treatment as well as increased vigilance in medical care.
The Endocrine Society, a global medical organisation dedicated to the advancement of hormone science and public health, has recommended screening patients who exhibit low potassium levels, an adrenal mass that shows up on a scan, a family history of early-onset hypertension, or signs of/stroke before age 40.
Patients with drug-resistant hypertension — defined as blood pressure that is uncontrolled despite the patient taking three different kinds of antihypertensive medications at their maximally tolerated doses – are highly advised to go for screening.
Screening entails a blood test to determine the aldosterone-to-renin ratio (ARR). Renin is an enzyme produced by the kidneys that triggers a chain reaction that leads to aldosterone production. When renin is low, aldosterone should be low; but in people with PA, aldosterone can be elevated even when renin levels are low.
In the case of a positive ARR, additional tests are needed to see if surgery is an option. If one adrenal gland is secreting excess aldosterone, removing that gland may cure or improve the disease. Surgery is not recommended when both glands are affected, in which case the patient is to take one of two drugs that block aldosterone. Both drugs have been reported to have different degrees of potency and several side effects.
Besides endorsing PA screening, The Endocrine Society is reaching out to care groups based in the US to develop newer guidelines for hypertension. In addition are clinical trials underway for new scanning techniques and procedures that could save the adrenal gland from irreversible inflammation, as well as two new classes of drugs that are much more tolerable to patients.
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