Conn’s syndrome

Conn syndrome: description

Conn syndrome (primary hyperaldosteronism) is an adrenal disorder in which the blood pressure is permanently too high (hypertension). An important role is played by the hormone aldosterone – one of the hormones that regulate the concentration of salts such as sodium and potassium in the blood. In Conn syndrome, the adrenal cortex produces too much aldosterone. As a result, urine excretes less sodium, but more potassium. Associated with this, more water remains in the bloodstream – high blood pressure develops, which is difficult to treat.

One primary hyperaldosteronism – So the body’s production of too much aldosterone – was first described in 1955 by the US physician Jerome Conn. For a long time, professionals considered Conn syndrome to be a very rare disease; now, however, it is believed that it could be the cause of up to 13 percent of high blood pressure cases. In many cases, however, Conn syndrome becomes not recognizedbecause they do not have a noticeably low potassium level.

Conn syndrome is the leading cause of secondary hypertension – high blood pressure associated with a specific underlying condition. Most prevalent, however, is primary hypertension due to adverse lifestyle and hereditary factors.

Conn syndrome: symptoms

The hallmark of Conn syndrome is measurable hypertension. Primary hyperaldosteronism does not necessarily trigger noticeable symptoms. Only some of those affected complain about specific high blood pressure symptoms:

• a headache
• red and warm face
• ear noise
• nosebleeds
• blurred vision
• difficulty in breathing
• reduced efficiency

Due to the permanent hypertension in Conn’s syndrome, however, various organs can be damaged, especially the heart, kidneys and eyes. Many sufferers develop kidney problems or cardiovascular disease over time. Their risk of arteriosclerosis (atherosclerosis or arteriosclerosis), heart attacks and strokes is even higher than that of people with primary hypertension, ie “normal” hypertension without adrenal disease.

About one in ten Conn syndrome patients also has one potassium deficiency (Hypokalemia). Potassium is a mineral that performs many important functions in the body, including muscle, digestion and cardiac rhythm regulation. Too low potassium levels in the blood can lead to muscle weakness, cramps, cardiac arrhythmias, constipation, increased thirst (polydipsia) and frequent urination (polyuria) in Conn’s syndrome.

Conn syndrome: causes and risk factors

The cause of Conn syndrome is one Disorder of the adrenal cortex, This is the outer part of the adrenals, two small organs that sit on the upper ends of the two kidneys. The adrenal cortex is one of the most important production sites for various hormones, the signaling substances of the body. It produces, among other things, the anti-inflammatory and metabolically active cortisol, but also various sex hormones – and aldosterone.

Aldosterone is responsible for regulating the body’s blood pressure and water balance in conjunction with other hormones – renin and angiotensin. This is why doctors also speak of the renin-angiotensin-aldosterone system, RAAS for short.

How the RAAS works

In simple terms, the RAAS works as follows: If, for some reason, the kidneys are not perfused well enough (for example, if the sodium level is too low or too low), certain cells in the kidneys produce renin, an enzyme with hormonal action. This enzyme breaks down angiotensinogen produced in the liver – the hormone angiotensin I is produced. Angiotensin I is converted to angiotensin II by another enzyme, the angiotensin converting enzyme (ACE). This in turn causes the blood vessels to contract. This increases the blood pressure. At the same time angiotensin II stimulates the adrenal cortex to form aldosterone. Aldosterone ensures that more water and sodium remain in the body. This increases the blood pressure additionally, as the blood volume in the vessels increases. The kidneys are again better supplied with blood and again pour less renin.

Disorders of the adrenal cortex

In Conn’s syndrome RAAS becomes unbalanced, as the adrenal gland produces too much aldosterone. This can have different causes:

• a benign adrenal cortex tumor (adenoma) that produces aldosterone
• a bilateral slight enlargement of the adrenal glands (bilateral adrenal hyperplasia)
• a unilateral enlargement of an adrenal gland (unilateral hyperplasia)
• a malignant tumor (carcinoma) of the adrenal cortex that produces aldosterone

However, unilateral hyperplasia and adrenal carcinoma are very rare causes of Conn’s syndrome.

Familial hyperaldosteronism

Very rarely is a hereditary cause behind the Conn syndrome, so the chronically increased aldosterone production – then one speaks of one familial hyperaldosteronism type I or type II. In type I there is a defect in the genetic material, as a result of which the pituitary gland produces too much of another messenger substance – the adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal cortex to produce aldosterone. In familial hyperaldosteronism type II, the genetic cause has not yet been clarified.

Conn syndrome: investigations and diagnosis

Conn syndrome usually starts with the diagnosis of high blood pressure. It is not uncommon for those affected to be treated for months or years before Conn syndrome is diagnosed. Sometimes they stand out because hypertension is difficult to adjust with various medications. Most often, however, primary hyperaldosteronism is diagnosed when accompanied by typical symptoms or by chance blood test a low potassium level is noticeable. Other blood levels are also changing in Conn’s syndrome: the sodium level rises, the magnesium level drops and the pH of the blood shifts slightly into the alkaline range (alkalosis).

Certainly, primary hyperaldosteronism can only be diagnosed by a targeted examination of the patient hormone levels in the blood plasma. The doctor can detect Conn syndrome if the aldosterone concentration is increased here and the renin content is lowered. The two values ​​are compared with the so-called aldosterone / renin quotient. A value above 50 indicates a possible Conn syndrome. However, levels may vary and be affected by medications – including high blood pressure such as diuretics, beta-blockers and ACE inhibitors – which often require multiple hormone tests to diagnose.

To secure the diagnosis Conn syndrome, one can Saline load test make sense. In this case, the affected person must lie about four hours quiet and gets during this time an infusion with a saline solution. In patients with a healthy adrenal gland, this causes the body to slow down aldosterone production and reduce hormone levels by half, while conn-syndrome has little effect on aldosterone production. Sometimes the effect of other drugs on aldosterone levels is also tested, for example with one Fludrocortisone suppression test and one Captopril test.

Further investigations are aimed at finding out the exact causes of Conn’s syndrome, for example an adenoma or enlargement of the adrenal cortex. Suitable for this purpose Imaging procedures such as computed tomography (CT) or magnetic resonance imaging (MRI). On the sectional images, the doctor can detect any tumors and other abnormalities of the adrenal cortex that cause the Conn syndrome.

Can also be helpful in finding the trigger for Conn syndrome Orthostatic test be. It measures how the renin and aldosterone levels change when the patient is in bed rest or spending several hours continuously in an upright posture (walking and standing). In adrenal enlargement, the body can regulate hormone production a little better than with an aldosterone-producing adenoma.

Conn syndrome: treatment

Bein Conn syndrome, the therapy is aimed at the cause in each case:

In a bilateral adrenal hyperplasia, ie a bilaterally enlarged adrenal cortex, are different drugs helpful. This mainly includes the aldosterone antagonist spironolactone. It blocks the “docking” (receptors) for aldosterone and thus prevents more potassium from being excreted and sodium being retained. Thus, the volume of fluid in the vessels is reduced, the potassium level remains constant and the blood pressure drops. Supplementing other antihypertensives may be used to get the hypertension under control.

If the Conn syndrome goes back to an aldosterone-producing adenoma, the doctors remove the tumor in one surgery – usually the same together with the whole affected adrenal gland. The healthy adrenals then take over their duties. While the potassium balance usually normalizes immediately, the blood pressure drops in the long term in the months following the operation. Even if a malignant adrenal cortex tumor is behind Conn syndrome, it usually requires surgery.

In rare cases, familial hyperaldosteronism type I is the trigger for Conn syndrome. In this case, the hormone ACTH causes the adrenal cortex to produce more aldosterone. Cortisone-like drugs (glucocorticoids) can suppress the ACTH effect in Type I; with type II they are ineffective.

Conn syndrome: disease course and prognosis

The prognosis for Conn’s syndrome depends on the underlying cause, how well it can be treated, and whether it succeeds in lowering blood pressure to a healthy level in the long term. The problem is that the Conn syndrome is often not recognized when the potassium level is still in the normal range – this is often the case in a bilateral adrenal hyperplasia of the case. Proper diagnosis and treatment significantly improves the prognosis.

However, the biggest problem with Conn syndrome is not the disease of the adrenal cortex itself, but its sequelae: the risk of cardiovascular disease, eye and kidney damage increases. Therefore, that should be Conn’s syndrome be treated in any case.