Primary Hyperaldosteronism

This is a condition where your adrenal gland may be secreting more aldosterone ( a blood pressure hormone) than required. this is a rare cause for high blood pressure

You would already have had some tests to check for this condition and your doctor would have explained the results to you. We need to increase your blood volume. this will cause your adrenal gland to reduce the release  of aldosterone

Contra indications

  • Heart Failure.
  • Severe uncontrolled hypertension,
  • renal insufficiency,
  • Uncontrolled Cardiac arrhythmia,
  • hypokalemia. (<3.0 mmol/l)

What we need to do

 

6 weeks before test

  • Stop the following for 6 weeks before test
    • spirinolactone/ Eplerinone ( aldosterone antagonists) for 6 weeks. We need to do this with caution and raise this with your doctor if you are worried
  • Please ensure you start an alpha blockers (eg doxazocin) and check blood pressure at home if possible

2 weeks before test

  • Stop the following for 2 weeks
    • beta blockers (eg propranalol, Bisoprolol),
    • calcium channel antagonists (amlodipine, nifidipine),
    • ACE inhibitors (Ramipril, enalapril)
    • Angiotensin 2 blockers
  • Please ensure you start an alpha blockers (eg doxazocin) and check blood pressure at home if possible

1 week before test

  • Check potassium level and ensure this is in normal range ( > 4 mmol/L) . If required, start potassium supplements.

METHOD

8 AM Patient arrives, FAsting since midnight . Fluids permissible. No caffeinated beverages

Intravenous canula to be inserted at 8 AM.

8 AM Bloods taken for plasma aldosterone, plasma renin activity, U & Es, Plasma metanephrine. Transport to lab urgently

8.30 AM to 9 AM Patient to remain sitting for at least 30 mins

9 AM Infusion of 0.9% saline to be infused over 4 hours, starting at 9.00 AM

Monitor Blood pressure, oxygen saturation and pulse rate hourly.

1 PM After infusion is complete, please take SAMPLE 2 for aldosterone, U & Es.

Patient can be discharged by 2 PM

INTERPRETATION

When fluid is infused, and plasma volume increases, aldosterone should be suppressed.

 

Post-infusion plasma aldosterone

<120 pmol/L Unlikely to be  primary hyperadosteronism

>240 pmol/L   likely primary hyperaldosteronism

Values between 120 – 240 pmol/L are indeterminate.. May require captopril challenge at a later date