Primary aldosteronism (hyperaldosteronism): Clinical sciences

Primary aldosteronism, also known as primary hyperaldosteronism or Conn syndrome, is a condition in which the adrenal glands produce an excessive amount of aldosterone. These individuals typically present with hypertension that is refractory to medical management. Now, the most common causes of primary aldosteronism include adrenal adenomas, idiopathic hyperaldosteronism, as well as a genetic condition called familial hyperaldosteronism.

Now, if your patient presents with a chief concern suggesting primary aldosteronism, first, you should perform an ABCDE assessment to determine if your patient is unstable or stable.

If the patient is unstable, stabilize the airway, breathing, and circulation. Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry. Finally, if needed, don’t forget to provide supplemental oxygen.

Now here’s a high-yield fact to keep in mind! A patient with primary aldosteronism can present with a hypertensive crisis, which occurs when the systolic pressure is above 180 or the diastolic pressure is above 120.

Blood pressure this high puts patients at risk for organ damage, such as acute myocardial infarction, acute renal failure, and intracranial hemorrhage.

Moreover, if there’s evidence of end-organ damage, the hypertensive crisis is often referred to as a hypertensive emergency. On the flip side, the hypertensive crisis in the absence of end-organ damage is sometimes referred to as hypertensive urgency.

In both cases, your patient requires immediate treatment with an IV antihypertensive, such as nitroprusside, with the goal of gradually lowering blood pressure over 24 hours. This way you are minimizing the risk of rapid drops in perfusion to vital organs and subsequent ischemic injuries.

Now that we're done with unstable patients, let’s go back to the ABCDE assessment and discuss the stable ones. First, obtain a focused history and physical examination and order a basic metabolic panel or BMP for short. Your patient may report symptoms like headaches, muscle cramps, weakness, polyuria, and polydipsia.

The most important history findings typically include persistent hypertension, often despite the use of several antihypertensive medications;

family history of early-onset hypertension, cerebrovascular accident, or primary aldosteronism. Additionally, some individuals can have a previous imaging study revealing an incidental adrenal mass.

On the other hand, the most important physical exam finding is elevated blood pressure, typically above 150/100. But, if your patient is taking 3 or more antihypertensives, you should consider primary aldosteronism if blood pressure is still over 140/90.

In both cases, lab results might reveal hypernatremia, hypokalemia, and an elevated serum bicarbonate level.

At this point, you should order a plasma aldosterone level and plasma renin activity.

By calculating the aldosterone to renin activity ratio you can screen your patient for primary aldosteronism. If the ratio is less than 20 to 1, the screening is negative, so consider an alternative diagnosis.

However, if the ratio is greater than 20 to 1, you should suspect primary aldosteronism.

To explain why the ratio is high in primary aldosteronism, recall that under physiologic conditions, renin levels increase when the kidneys are hypoperfused.

This can occur in the setting of hypovolemia, or hypotension. Renin then activates the angiotensin pathway, which in turn stimulates the adrenal glands to increase aldosterone secretion, with a net result of increased water reabsorption and an increase in blood pressure.

In a healthy individual, we would only expect to see aldosterone levels increase in the setting of increased renin levels, yielding a normal aldosterone-to-renin ratio.

However, in primary aldosteronism, there is an inappropriate increase in aldosterone levels even when renin levels are low, which is why the aldosterone to renin ratio is abnormally high.

Now, once you suspect it, you need to determine whether or not the criteria for diagnosis of primary aldosteronism are met. These include hypertension, hypokalemia, an aldosterone level greater than 20 nanograms per milliliter, and plasma renin activity that is below the lower limit of normal, so below 1.0 ng/mL/hour, or even undetectable.