Primary aldosteronism

Primary aldosteronism (PA), also known as primary hyperaldosteronism, refers to the excess production of the hormone aldosterone from the adrenal glands, resulting in low renin levels and high blood pressure. This abnormality is caused by hyperplasia or tumors. About 35% of the cases are caused by a single aldosterone-secreting adenoma, a condition known as Conn's syndrome.

Many patients experience fatigue, potassium deficiency and high blood pressure which may cause poor vision, confusion or headaches. Symptoms may also include: muscular aches and weakness, muscle spasms, low back and flank pain from the kidneys, trembling, tingling sensations, dizziness/vertigo, nocturia and excessive urination. Complications include cardiovascular disease such as stroke, myocardial infarction, kidney failure and abnormal heart rhythms.

Primary hyperaldosteronism has a number of causes. About 33% of cases are due to an adrenal adenoma that produces aldosterone, and 66% of cases are due to an enlargement of both adrenal glands. Other uncommon causes include adrenal cancer and an inherited disorder called familial hyperaldosteronism. PA is under diagnosed; the Endocrine Society recommends screening people with high blood pressure who are at increased risk, while others recommend screening all people with high blood pressure for the disease. Screening is usually done by measuring the aldosterone-to-renin ratio in the blood (ARR) whilst off interfering medications and a serum potassium over 4, with further testing used to confirm positive results. While low blood potassium is classically described in primary hyperaldosteronism, this is only present in about a quarter of people. To determine the underlying cause, medical imaging is carried out.

Some cases may be cured by removing the adenoma by surgery after localization with adrenal venous sampling (AVS). A single adrenal gland may also be removed in cases where only one is enlarged. In cases due to enlargement of both glands, treatment is typically with medications known as aldosterone antagonists such as spironolactone or eplerenone. Other medications for high blood pressure and a low salt diet, e.g. DASH diet, may also be needed. Some people with familial hyperaldosteronism may be treated with the steroid dexamethasone.

Primary aldosteronism is present in about 10% of people with high blood pressure. It occurs more often in women than men. Often, it begins in those between 30 and 50 years of age. Conn's syndrome is named after Jerome W. Conn (1907–1994), an American endocrinologist who first described adenomas as a cause of the condition in 1955.