💡 TLDR Primary Care - Primary Aldosteronism (#032)

In This Issue:

✅ Summarized guidelines on primary aldosteronism

⭐ Key likelihood ratios for considering the diagnosis

⏯️ Check out our evaluation and management pathway!

📈 And more!

💡 Deep Dive: Primary Aldosteronism

In-depth review of key recent guidelines

This week, we’ll review the latest clinical guidelines on Primary Aldosteronism (PA). Also known as Conn’s syndrome, PA is an endocrine disorder characterized by excessive aldosterone secretion from the adrenal glands and is a common cause of treatment-resistant hypertension. In fact, PA has a prevalence of 5-20% in patients with secondary hypertension. Patients with PA will often have treatment-resistant HTN along with hypokalemia. Undiagnosed, this disorder can lead to poorly controlled blood pressure and increased cardiovascular morbidity.

Guidelines on Primary Aldosteronism - and the related topic of incidentally discovered adrenal masses - are published by the Japanese Endocrine Society (2022), Canadian Urological Association (2023), and the American Association of Endocrine Surgeons (2022), among others.

For a full review of the comprehensive Primary Aldosteronism guidelines, head over to Pathway. We’ll cover some key takeaways below (with the recommendation strength in parentheses). 

1. Diagnosis and Screening:

• Consider screening for hyperaldosteronism in hypertensive patients with any of the following: (C)
  • Unexplained spontaneous hypokalemia (K < 3.5 mmol/L)
  • Marked diuretic-induced hypokalemia (K < 3.0 mmol/L)
  • Resistance to treatment with > 3 drugs
  • An incidental adrenal adenoma
• Consider obtaining CT or MRI as initial imaging for detecting adrenal adenomas in patients with hyperaldosteronism. (B)

⭐ Key Likelihood ratios in Primary Aldosteronism:

Positives - Aldosterone to renin ratio > 13.1ng/mL/h (LR +8.68), decreased serum plasma renin activity (LR +8.2), increased serum aldosterone (LR +4.2)

Negatives - Normal serum plasma renin activity (LR -0.1), normal serum aldosterone (LR -0.32), aldosterone to renin ratio < 13.1 ng/mL/h (LR -0.32)

2. Screening Testing:

• Obtain a plasma aldosterone-to-renin ratio (ARR) as the initial screening test to evaluate for PA. (B)
• Hold pharmacological agents that are known to markedly affect ARR (aldosterone antagonists, potassium-sparing and -wasting diuretics) at least 4-6 weeks before testing. (I)
• Obtain plasma aldosterone and plasma renin activity in the morning after the patient has been ambulatory (sitting, standing, or walking) for at least 2 hours. (I)

3. Confirmatory Testing

• Perform one or more confirmatory tests to definitively confirm or exclude the diagnosis of PA in patients with a positive aldosterone-to-renin ratio. (B)

• Saline loading tests:
  • Administer 2L of normal saline IV over 4 hours with the patient in a recumbent position ( contraindicated in the presence of severe, uncontrolled HTN or congestive HF). Define PA as a postinfusion plasma aldosterone > 280 pmol/L. Recognize that PA is unlikely if < 140 pmol/L, and values in between are considered indeterminate
  • Administer > 200 mmol/day of oral sodium (equivalent to > 5 g/day of sodium) for 3 days. Define PA as a 24-hour urinary aldosterone > 33 nmol/day (measured from the morning of day 3 to the morning of day 4). Recognize that PA is unlikely if < 28 nmol/day.

• Plasma aldosterone to renin ratio:
  • Define PA by a plasma aldosterone to renin ratio of > 1400 pmol/L/ng/mL/hour (or > 270 pmol/L/ng/L), with a plasma aldosterone > 440 pmol/L.

• Captopril suppression test:
  • Administer 25-50 mg of captopril PO after the patient has been sitting or standing for 1 hour. Measure renin and plasma aldosterone levels while seated at time 0 and 1-2 hours after ingestion. Recognize that PA is unlikely if plasma aldosterone is suppressed by > 30% after ingestion. Recognize that plasma aldosterone level remains elevated in PA, while renin levels remain suppressed.

4. Medical Management:

• Consider deferring adrenal venous sampling in patients < 35 years old with cross-sectional imaging demonstrating a unilateral adenoma and a radiologically normal contralateral gland, since adrenalectomy directed by CT alone has a cure rate similar to adrenalectomy guided by adrenal venous sampling in these patients. (C)

➡️ Check out our interactive pathway for primary aldosteronism!

• Initiate mineralocorticoid receptor antagonists in patients with bilateral PA, and patients with unilateral PA in whom surgery is not indicated or desired. (A)
• Initiate mineralocorticoid receptor antagonists for the treatment of PA to prevent target-organ damage mediated by aldosterone, even in patients with reasonable BP control and normokalemia on standard medication. (B)
• Administer the lowest effective dose of corticosteroids required to lower ACTH and normalize BP and potassium levels as first-line treatment in patients with corticosteroid-remediable aldosteronism. (B)

5. Surgical Management:

• Initiate appropriate treatment to prevent perioperative complications in patients undergoing adrenalectomy. (B)
• Perform laparoscopic adrenalectomy in patients with unilateral primary hyperaldosteronism to lower risk of new-onset AF, CKD, stroke, and all-cause mortality. (B)
• Recognize that performing unilateral adrenalectomy is a highly effective means of normalizing plasma aldosterone concentrations, improving HTN and preventing target organ damage in patients with PA. (A)
• Recognize that the impact of adrenalectomy on BP control in patients with unilateral PA is affected by the following factors: (B)
  • Number of antihypertensive medications before surgery
  • Duration of HTN
  • Gender, BMI, age, and renal function
• Recognize that a decrease in the eGFR in the early stage after adrenalectomy predicts a favorable outcome in the long-term renal function. (B)

If you enjoyed this newsletter, please consider forwarding it to a friend or colleague who would enjoy it too.

If a friend sent you this, get the next newsletter by signing up here.

Who’s Pathway? We’re a global community of clinicians working to democratize medical knowledge and make practicing evidence-based medicine more accessible, fun, and not so overwhelming.

Warm regards,

- The Pathway Team

Pathway Medical Inc. | All rights reserved | Unsubscribe