Primary Aldosteronism and Endocrine Hypertension

Primary aldosteronism (PA) is a condition that results when one or both of the adrenal glands—two small glands located above each kidney—produce too much of the hormone aldosterone. Having high levels of aldosterone causes the body to retain sodium (salt) and lose potassium. Sodium retention causes fluid build-up, which raises blood pressure.

In the past, it was assumed that PA was fairly rare, but recent evidence shows it occurs in as many as one in ten patients with high blood pressure. PA is more common in people with severe, uncontrolled high blood pressure or blood pressure that is resistant to drug treatment. People with PA are at greater risk of heart disease and stroke than are others with the same degree of high blood pressure but without PA.

Who should be tested for PA?
Certain groups of people are known to be at high risk for PA and should be tested, including those with:

• moderate (>160-179/100-109 mm Hg), severe (>180/110 mm Hg), or resistant high blood pressure (resistant means that three medications administered at the same time fail to bring the blood pressure into the normal range)
  
  
• high blood pressure and a low level of potassium in the blood
  
  
• high blood pressure and an adrenal tumor (which may have been discovered when a computerized imaging study—e.g., CT scan or MRI scan—was done for other reasons)
  
  
• high blood pressure at a young age
  
  
• family history of stroke at a young age
  
  
• high blood pressure and a parent, sibling, or child with PA

Diagnosis of PA
A blood test—the aldosterone/renin ratio (ARR)—is used to detect cases of PA in these patient groups. Renin is a protein released by the kidneys to help regulate blood pressure. To determine the ARR, levels of aldosterone and renin are measured in a blood sample. Diagnosis of PA is based on having both very high levels of aldosterone and low levels of renin.

Treatment of PA
Treatment of PA depends on the underlying cause.

• Aldosterone-producing adenoma (a noncancerous tumor): If only one adrenal gland is overproducing aldosterone, it can be surgically removed. Some people continue to have high, but less severe, blood pressure after surgery, but it can be managed with medication more easily than before surgery.
  
  
• Hyperplasia (excessive growth of cells): If both adrenals are overactive, medical treatment with a mineralocorticoid receptor (MR) antagonist, such as the drug spironolactone, is recommended. MR antagonists block the action of aldosterone in the body.
  
  
• Glucocorticoid-remediable aldosteronism (a rare, inherited condition): The recommended treatment is the lowest dose of a glucocorticoid (that is, a steroid such as dexamethasone or prednisone) that can normalize blood pressure and potassium levels in the blood.