Primary aldosteronism: a neglected and difficult to treat cause of hypertension

Some friends may be unfamiliar with the disease of "primary aldosteronism", but it is such a common disease that is unfamiliar to the general public, and it is also the most common cause of secondary hypertension, which is easily overlooked in refractory hypertension. So, what is primary aldosteronism? Why is it not easy to detect? How to treat it? Next, the medical student will take you through a comprehensive understanding of primary aldosteronism.

Before introducing primary aldosteronism, let's first briefly understand its pathological organ: the adrenal gland. The adrenal gland is located above the kidneys and is a crucial endocrine organ in the human body. It can secrete various hormones, such as adrenaline and glucocorticoids, which are commonly known as adrenal glands. The hormone closely related to the onset of primary aldosteronism is aldosterone, secreted by the adrenal cortex. The main function of aldosterone is to regulate the metabolism of sodium ions, potassium ions, chloride ions, and water. The metabolic characteristics of sodium ions and potassium ions are sodium retention and potassium excretion. By acting on the "sodium potassium" exchange channel in the renal tubules, sodium ions are retained in the blood, while potassium ions are excreted into the urine. When lesions occur in the adrenal cortex, such as adrenal adenoma, adrenal cortical hyperplasia, adrenal cancer, etc., the secretion of aldosterone increases, leading to electrolyte disorders and ultimately leading to primary aldosteronism.

The function of aldosterone is to preserve sodium and excrete potassium, and under normal circumstances, the two can be maintained in a relatively balanced state without causing metabolic disorders. When the secretion of aldosterone in the body increases, the amount of sodium ions retained in the blood and potassium ions excreted into the urine increase, leading to an increase in blood sodium and a decrease in blood potassium.

• When the sodium ion in the blood increases, it will cause retention of water and sodium, increase the blood volume, and thus raise the blood pressure. It is the most common cause of secondary hypertension. At the same time, it also accounts for a high proportion of hypertension patients, about 6% - 10%. At the beginning of the disease, the blood pressure of most patients is around 170/100mmHg, but as the condition progresses, the blood pressure may continue to rise, and even progress to refractory hypertension.
• When potassium ions in the blood decrease, it can cause hypokalemia. The normal range of blood potassium is 3.5-5.5mmol/L, and in patients with primary aldosteronism, the blood potassium can be as low as 2.0-3.0mmol/L. What are the hazards? Hypokalemia can cause arrhythmia, such as ventricular fibrillation, which is the main cause of sudden cardiac death; When involving the neuromuscular system, muscle weakness and muscle paralysis may occur; When involving the kidneys, it can cause urinary tract infections, pyelonephritis, and even renal dysfunction.

Through the above introduction, it can be found that the characteristics of primary aldosteronism are "hypertension and hypokalemia". When these two symptoms appear, screening should not be difficult, at least with relevant clues. But please note that not all patients will experience typical symptoms. The most common symptom of this disease is hypertension, which is also the earliest symptom of the disease. Most patients do not experience hypokalemia when their blood pressure increases, so they are easily diagnosed with primary hypertension and treated accordingly. Due to the unresolved etiology, patients with primary aldosteronism generally have poor antihypertensive effects, and some patients cannot control their blood pressure within the target range by combining multiple antihypertensive drugs. And another typical symptom of it is hypokalemia, which may appear 3 to 4 years after the increase in blood pressure or may no longer appear, because research has found that only 9% -37% of patients with primary aldosteronism experience hypokalemia, which increases the difficulty of screening for the disease. Compared to primary hypertension, hypertension caused by primary aldosteronism causes greater damage to target organs such as the heart and kidneys. Therefore, early detection and treatment are necessary.

For patients with positive screening results, diagnostic tests should also be conducted, including sodium infusion test, oral sodium load test, captopril test, and fluhydrocortisone inhibition test, with sodium infusion test being the most commonly used. After the diagnosis is confirmed, in order to develop a reasonable treatment plan, all patients with primary aldosterone should undergo adrenal CT examination for classification diagnosis; If adrenal CT indicates abnormal adrenal morphology and surgical indications are available, bilateral adrenal vein blood collection tests can be arranged if necessary. This examination has higher specificity and sensitivity compared to adrenal CT.

The treatment of primary aldosteronism can be divided into drug treatment and surgical treatment, and the specific treatment plan should be determined by factors such as etiology classification, tolerance to surgery, and drug response. Some patients require medication treatment, while others require surgical treatment, such as adrenal cortical cancer, which is a malignant tumor and should be surgically removed as soon as possible; If bilateral adrenal hyperplasia is treated surgically, it will lose the endocrine function of the adrenal gland and medication should be chosen for treatment; If it is an aldosterone tumor, surgical treatment can be chosen, and the eradication rate of hypertension after surgery is relatively high. Of course, if the patient has no surgical intention or is intolerant to surgery, they can only take medication treatment. It should be noted that due to the fact that primary aldosteronism can cause renal dysfunction, some patients may also be accompanied by primary hypertension. Therefore, some patients may still need medication to lower blood pressure after surgical treatment.

To sum up, primary hyperaldosteronism is the most common cause of secondary hypertension. The reason for elevated blood pressure is that the adrenal cortex secretes too much aldosterone, which causes excessive sodium ion retention in the body, causing elevated blood pressure. In the early stage, the disease can only have hypertension, usually without hypokalemia, so it is easy to be diagnosed as primary hypertension. Because the cause of the disease is not removed, the effect of lowering blood pressure of the disease is poor, and it is easy to progress to refractory hypertension. However, after Etiological treatment or removal of the cause, the blood pressure can be improved or the hypertension can be eradicated.

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Note: The content of the article is only for health science popularization, not for medical advice or opinions, and does not meet the conditions for medical guidance.