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Hyperaldosteronismus primarius
A hormonal and causally treatable form of high blood pressure — and a normal potassium expressly does not rule it out.
Also known as: Primary aldosteronism · Conn adenoma · hormonal high blood pressure · aldosterone-renin ratio
Open in the tool — with search and all the links →This compilation is for information and replaces neither medical diagnosis nor treatment. If you have symptoms, see a doctor.
One of the most important and at the same time most frequently overlooked causes of high blood pressure. The adrenal glands make too much aldosterone, the hormone that holds salt and water in the body — blood pressure rises, independently of lifestyle and weight. Among all people with high blood pressure, depending on the study about 3 to 14 percent have this cause; with blood pressure that cannot be controlled despite several medicines it is up to 20 percent. A persistent misunderstanding delays the diagnosis: many expect a low potassium. But that is the exception — most of those affected have a completely normal potassium, and looking only for that misses the majority. Suspicion is worthwhile above all with high blood pressure that starts early, is unusually high, does not fall despite three medicines, comes with a low potassium, or occurs together with an adrenal finding on ultrasound or CT. The first step is simple: a blood test relating aldosterone and renin to each other — the aldosterone-renin ratio. Then follow a confirmation test and the distinction whether only one adrenal is involved or both. Therein lies the good news: unlike ordinary high blood pressure, here there is a causal treatment. If the source sits in a single benign nodule, removing it can clearly lower or even normalise blood pressure; if both adrenals are involved, a drug that blocks the action of aldosterone works very specifically. The assessment also matters because too much aldosterone damages heart, vessels and kidneys more than the blood pressure figure alone suggests.
If blood pressure does not reach target despite three medicines, looking for a cause is worthwhile — up to one in five then has Conn syndrome.
The expectation that potassium must be low is the commonest reason for a missed diagnosis. The majority have a normal value.
The aldosterone-renin ratio is simple to measure. Important: some blood pressure medicines distort it — discuss preparation with the doctor, do not stop anything on your own.
If the source is a single benign nodule, removing it can strongly lower or normalise blood pressure. If both adrenals are involved, a targeted medicine works.
Less salt supports the treatment but does not replace it — the cause lies in the hormone, not in the salt shaker.
Too much aldosterone damages heart, vessels and kidneys more than the blood pressure figure suggests. That is an additional argument for really looking for the cause.
Spironolactone and eplerenone block the effect of aldosterone — they lower blood pressure and raise potassium, they do not remove the nodule. Before the blood test, certain blood pressure drugs must be paused for four to six weeks, otherwise the value cannot be interpreted; that is the most common reason for a false result. With a one-sided finding, surgery normalises blood pressure in about one in three and improves it in most of the rest.
In about five to ten in a hundred people with high blood pressure it is the cause, and in up to twenty per cent with pressure that is hard to control — making it the most common treatable cause, and still rarely looked for. Low potassium is found in only about one in three; its absence therefore rules nothing out. Before measuring, certain blood pressure drugs are paused for four to six weeks. After surgery the pressure normalises in about a third.
Values that do not reach target under three drugs, one of them a water tablet. That is the most common reason to think of this cause, and the test for it is a single blood draw.
Muscle weakness, cramps, constipation, passing much water and thirst at night with a low potassium. Important: in the majority the potassium is normal — a normal value rules nothing out.
High blood pressure before the age of forty, especially in a slim build, or a pressure that suddenly gets clearly worse although nothing has changed.
A nodule noticed on a scan done for another reason, together with high blood pressure. Sleep apnoea is also more common with this cause.
A low potassium is a strong clue — but NOTE: most affected people have a normal potassium. A normal value does not rule out Conn syndrome.
Can be in the upper range or raised because salt is retained — on its own, however, of little significance.
Too much aldosterone puts extra strain on the kidneys over the years — one more reason to find the cause.
Makes sure the muscle lets go again after tensing. A lack favours cramps, twitching and inner restlessness — and the blood value reflects the store poorly.
Sets the excitability of muscle and nerve. A low value causes weakness and cramps, a high one is dangerous for the heart rhythm — here one measures rather than guesses.
Sets off the tensing in the muscle in the first place. A low value causes tingling around the mouth and in the fingers and cramping of the hands.
With heavy sweating both are lost together. Drinking only water dilutes the sodium further — with long exertion salt belongs with it.
Potassium is here the key value: too much aldosterone drives it out through the kidney, and calf cramps, muscle weakness and passing more water follow. Potassium in capsules refills, but does not remove the cause — and after treatment it can conversely become too high.
The most important point for the diagnosis: liquorice produces exactly the same picture — high blood pressure, low potassium — without any adrenal gland being involved. From about 100 g daily over a few weeks this is described, and it disappears after leaving it off. Anyone who eats a lot of liquorice says so before the work-up.
Unlike in most forms of high blood pressure, a low-salt diet is here not just an accessory: the effect of aldosterone on blood pressure hangs on how much salt is present. Only before the test the salt is not altered — otherwise the measurement is wrong.
Effective when deficient; effects on sleep and stress plausible but moderate. Too much causes loose stool.
Here produced in excess. It holds back salt and water and drives potassium out — from which comes the hard-to-control high blood pressure with a low potassium.
The counterpart. What decides is the ratio of the two: much aldosterone with suppressed renin. Several blood pressure drugs distort the measurement — that belongs discussed beforehand.
Too much aldosterone drives potassium out and sodium in. Potassium-rich food such as bananas, potatoes, apricots and pulses balances it; salt is limited. Before the work-up neither should be changed on one’s own — it distorts the measurement.
Limiting salt and eating potassium-rich food balances what too much aldosterone does. Before the work-up neither belongs changed on one’s own — it distorts the measurement.