Title: Understanding Primary Aldosteronism: Diagnosis and Treatment
Overview:
Primary aldosteronism, commonly referred to as "原醛症" in Chinese, is a condition characterized by excessive aldosterone secretion due to adrenal cortical lesions. This leads to water and sodium retention, increased body fluid volume, elevated blood pressure, and suppression of the renin-angiotensin system, but without regulation by sodium load. This article delves into the diagnosis and treatment of primary aldosteronism, highlighting its significance in hypertension management.
Diagnosis:
The progression of primary aldosteronism is divided into three stages: early, with hypertension and no hypokalemia; mild potassium deficiency with hypertension; and severe potassium deficiency with hypertension. Common symptoms include hypertension, cardiovascular lesions, stroke, muscle weakness, periodic paralysis, peripheral numbness, tetany, polyuria, nocturia, polydipsia, increased risk of urinary tract infections, increased urine protein, and specific ECG patterns indicative of hypokalemia.
Key diagnostic tests include blood and urine biochemical tests, which often show low blood potassium levels (usually 2-3 mmol/L or lower), normal or slightly elevated blood sodium levels, and normal or slightly elevated blood pH and CO2 binding capacity. Plasma and urine aldosterone levels are typically elevated, with a plasma aldosterone to renin activity ratio greater than 30 suggesting the possibility of primary aldosteronism and greater than 50 being diagnostic.
Imaging techniques such as adrenal B-ultrasound, high-resolution CT, and MRI can detect aldosterone-producing adenomas. Additional tests include plasma ACTH and cortisol concentration measurements, and adrenal venous sampling. The diagnosis also involves distinguishing primary aldosteronism from other conditions such as non-aldosterone mineralocorticoid excess syndrome, Liddle syndrome, and secondary aldosteronism associated with hypertension and hypokalemia.
Treatment:
The definitive treatment for aldosterone-producing adenomas is surgical resection. For idiopathic hyperplasia, medication is the preferred approach.
Surgical Treatment: Before surgery, a low-sodium diet and spironolactone (aldosterone antagonist) are often prescribed. Spironolactone is typically started at 120-240 mg daily, divided into several doses, and continued until blood potassium levels normalize and blood pressure decreases. Hydrocortisone is administered intravenously during surgery and gradually tapered off over about a week. Adenoma surgery generally has good outcomes.
Medical Treatment: Spironolactone is the first-line medication, used in a similar manner to the surgical preparation. Eplerenone can be an alternative. Long-term use of spironolactone may lead to side effects such as gynecomastia, impotence, and menstrual irregularities in women, and can be switched to other potassium-sparing diuretics like amiloride or triamterene. Antihypertensive medications may also be necessary.
Calcium channel blockers can reduce aldosterone production in some patients, restoring blood pressure and potassium levels. Angiotensin-converting enzyme inhibitors may also be effective for patients with glucocorticoid-remediable aldosteronism (GRA). For GRA patients, dexamethasone or prednisone is typically used, with the addition of calcium channel blockers for difficult-to-control hypertension.
Aldosterone-producing adenocarcinoma has a poor prognosis, often presenting at a stage where surgical resection is no longer an option. Chemotherapy with drugs like mitotane, aminoglutethimide, and ketoconazole may temporarily alleviate symptoms but do not significantly improve the course of the disease.
Conclusion:
Early diagnosis and appropriate treatment of primary aldosteronism are crucial for managing hypertension and preventing complications. If you suspect primary aldosteronism, it is important to consult with a healthcare professional for an accurate diagnosis and tailored treatment plan.