Primary Hyperaldosteronism, also known as Conn’s syndrome, is a rare disease caused by an excess in the synthesis of a naturally occurring hormone in our bodies known as aldosterone. This hormone is responsible for the regulation of the electrolytes sodium and potassium in our blood, hence regulating our blood pressure and maintaining the rhythm of our hearts. As much as this hormone is crucial for survival, its excess could lead to catastrophic consequences.
To better understand the nature of this disease, it is important to understand the fundamental principles regarding this hormone production and its regulation. Aldosterone is synthesized in the adrenal glands, two triangular shaped glands that sit on top of the kidneys. Different areas of the gland are responsible for the production of different hormones, for example the Zona glomerulosa produces aldosterone, the zona fasciculata produces corticosteroid, and the zona reticularis produces the sex hormone androgen.
Aldosterone, like any other hormone, is regulated by another hormone that is released from the kidneys known as Renin. The kidneys have a group of cells (juxta glomerular cells) that are highly sensitive to the pressure of blood flowing through the kidneys. If the blood pressure drops, the kidney releases Renin that leads to the release of aldosterone, which in turn acts on the kidney tubules to retain sodium and water to maintain the normal blood pressure level. Once the blood pressure is controlled , the kidney stops producing renin and hence exerts its negative feedback and consequently, less aldosterone is released.
THE NATURAL (PHYSIOLOGICAL) ROLE OF ALDOSTERONE
Aldosterone is primarily responsible for the regulation of the blood pressure through sodium and water retention from the kidneys. Holding back of sodium causes the excretion of potassium, therefore, excess functioning of the hormone causes an excess in sodium in the blood (which causes high blood pressure) accompanied by a low potassium level, a condition known as hypokalemia.
MORE DOES NOT ALWAYS MEAN BETTER !
So what causes this hormone to be produced in excess? As mentioned earlier, aldosterone is synthesized in the adrenal glands. The most common cause of primary hyperaldosteronism is a condition known as bilateral adrenal hyperplasia. To break it up into simpler terms, bilateral indicates both adrenal glands, and hyperplasia is the increase in the size of the glands. Another cause could be due to a tumor on the adrenal gland, known as a cortical adenoma. The resultant mass is usually non-cancerous , however, cancerous tumors may rarely arise as well.
WHEN IS HIGH BLOOD PRESSURE CONSIDERED A RED FLAG?
Not every case of blood pressure leads physicians to considering Conn’s syndrome. High blood pressure is most often primary with no underlying organic disease. However, there are certain signs that, if present, would warrant further investigations to dig for the underlying condition causing the high blood pressure. Some of these are:
-High blood pressure in patients less than 30 years
-Three or more blood pressure lowering medications are required to control the high blood pressure
-An abdominal mass (indicates an adrenal mass maybe present)
-Lab tests showing low potassium level
HOW IS CONN’S SYNDROME DIAGNOSED?
Initially, a high blood pressure is noted usually while taking the vital signs of the patient. Basic blood tests would reveal an imbalance in the electrolyte level (ie, a high sodium and a low potassium level). Hormonal analysis would reveal a shooting aldosterone level and a low renin level. Measuring renin would allow the physician to determine if the cause of high aldosterone was primary due to an adrenal cause or secondary to another underlying cause
Ps: Renin is the hormone responsible for the negative feedback on aldosterone, and if low would indicate a high aldosterone level secondary to an adrenal cause- Primary hyperaldosteronism). Once primary hyperaldosteronism is suspected, a CT scan or an MRI can be done on the abdomen to visualize the adrenal mass.
Once primary hyperaldosteronism is suspected, a CT scan or an MRI can be done on the abdomen to visualize the adrenal mass.
TREATMENT: MEDICATIONS OR SURGERY?
Conn’s syndrome can only be completely cured by excising the tumor, and this is possible if the hyperplasia or tumor arises from a single adrenal gland. However, as mentioned earlier, most cases of Conn’s syndrome are due to hyperplasia of both adrenal glands, making medications the preferred modality of treatment to control the disease.
Medications that are used in treatment of Conn’s syndrome mainly target blocking of the action of aldosterone on the kidneys ( known as anti-aldosterone). The most common drug used is Spironolactone, a common diuretic that can be used for its anti-aldosterone “side effect”.
Antagonizing aldosterone would lead to an elevation in salt and water excretion and an increase in potassium retention, leading to a lower blood pressure with a “potassium sparing” effect.
The most common adverse effects of spironolactone are due to its feminizing effects as it also acquires anti-androgen properties. If the patient is disturbed by these side effects, an alternative drug can be used, called eplerenone, which has a similar anti- aldosterone action, and spares the anti-androgen effects.