Is hypertension required for the diagnosis of primary hyperaldosteronism in non‑pregnant and pregnant adults?

Is Hypertension Required to Diagnose Primary Aldosteronism?

No, hypertension is not an absolute requirement for diagnosing primary aldosteronism (PA), though it is present in the vast majority of cases and serves as the primary trigger for screening in non-pregnant adults. In pregnant women, the diagnosis is particularly challenging and typically deferred until after delivery.

Non-Pregnant Adults

The most recent 2025 Endocrine Society guideline recommends screening all individuals with hypertension for PA by measuring aldosterone and renin to determine the aldosterone-to-renin ratio (ARR) 1. However, this does not mean hypertension is required for the diagnosis itself—rather, it's the clinical context that prompts screening.

Key Diagnostic Considerations:

• PA can be diagnosed without hypertension in rare cases, particularly when patients present with:

  • Spontaneous hypokalemia
  • Plasma aldosterone >20 ng/dL with suppressed renin
  • Adrenal incidentalomas discovered for other reasons 2

• The diagnosis is biochemical, based on:

  • Elevated ARR (>30) indicating autonomous aldosterone secretion 3
  • Confirmatory testing showing aldosterone levels remain elevated despite suppression attempts
  • Lateralization studies to determine unilateral vs. bilateral disease 1

• Hypertension is the most common manifestation (present in ~90-95% of PA cases), making it the practical screening trigger, but the underlying pathophysiology is excess aldosterone production regardless of blood pressure status 3, 2.

Screening Triggers Beyond Simple Hypertension:

The guidelines emphasize screening in specific high-risk scenarios 3:

• Resistant hypertension (most important)
• Hypokalemia (spontaneous or diuretic-induced)
• Adrenal incidentaloma
• Family history of early stroke (<40 years)
• First-degree relative with PA
• Atrial fibrillation
• Obstructive sleep apnea

Pregnant Adults

Diagnosing PA during pregnancy is extremely difficult and generally should not be attempted using standard criteria 4.

Why Pregnancy Complicates Diagnosis:

• Pregnancy is a physiologic hyperreninemic-hyperaldosteronism state 4:

  • Plasma renin activity rises 4-7 fold by term
  • Aldosterone levels increase up to 10-fold above baseline
  • Additional renin sources from uterus, ovaries, and placenta
  • Estrogen stimulates renin and aldosterone secretion
  • Progesterone acts as a competitive mineralocorticoid receptor antagonist

• The ARR does not apply during pregnancy because both aldosterone and renin are physiologically elevated 4

Clues Suggesting PA During Pregnancy:

While definitive diagnosis should wait until after delivery, consider PA if 4, 5:

• Plasma renin activity <4 ng/mL/h (suppressed despite pregnancy)
• Persistent hypokalemia (though may be masked by progesterone's mineralocorticoid receptor antagonism)
• Hypertension with suppressed renin and elevated aldosterone in the clinical context

Critical Management Points for Pregnancy:

• Confirmatory tests (saline infusion, captopril test) are contraindicated during pregnancy due to volume expansion risks and potential teratogenicity 4

• Definitive diagnosis must wait until after delivery 4, 5

• If PA was diagnosed before pregnancy:

  • Unilateral disease: Adrenalectomy should be performed prior to conception 4
  • Bilateral disease: Discontinue spironolactone (teratogenic) and switch to pregnancy-safe antihypertensives

• PA during pregnancy carries significant risks 5, 6:

  • High rate of preeclampsia (early and late-onset)
  • Preterm delivery
  • Intrauterine growth restriction
  • Cesarean section often required

• Treatment during pregnancy: Use pregnancy-safe antihypertensives (methyldopa, beta-blockers, amiloride if needed) rather than mineralocorticoid receptor antagonists 4

Clinical Pitfalls to Avoid:

• Don't dismiss the possibility of PA in normotensive patients with unexplained hypokalemia or adrenal masses
• Don't attempt standard PA diagnostic protocols during pregnancy—defer until postpartum
• Don't overlook PA in women with pregnancy-related hypertension—up to 25% of women with hypertension and prior hypertensive disorders of pregnancy may have PA 7, 8
• In elderly patients, consider empiric mineralocorticoid receptor antagonist treatment rather than extensive testing if comorbidities make diagnostic procedures risky 4

The bottom line: While hypertension is the primary clinical manifestation prompting PA screening in non-pregnant adults, the diagnosis itself is biochemical and does not absolutely require hypertension. In pregnancy, standard diagnostic criteria cannot be applied, and definitive diagnosis should be deferred until after delivery.