We had a great Ambulatory Report today with the help of our own Christian Ngo and Endocrinologist Dr. Abramowitz, teaching us how to workup/manage adrenal incidentalomas:
- All patients:
- cortisol (1mg dex suppression test: am cortisol <1.8 rules out and >5 rules in). 24 hour urine cortisol is only used in patients where suspicion for Cushings is high or in patients (ie on HRT or with liver disease) where binding globulins may interfere with the results.
- metanephrines/catecholamines (24 hour urine: >4x ULN rules in). Free serum metanephrines are only useful in patients who you have a very high suspicion of a pheo. Remember that TCAs and SNRIs can lead to falsely elevated metanephrines/catecholamines.
- Only patients with HTN (no matter how mild):
- Renin/Aldo. Abramowitz recommends using the “Texas Two-Step” guidelines by Dr. Auchus. The most important lesson to learn from this paper is that a suppressed renin is more important than an elevated aldosterone. A renin <1 and aldosterone >15 gives you the diagnosis. Avoid using the ratio of >20 that we learned for Step 1. Remember that aldosterone antagonists (aldactone) will completely interfere with the test. ACE-I/ARBs do to a lesser extent so if their renin/aldo studies are +, then you have the diagnosis, however, if their studies are indeterminate/negative, either refer to Endocrine for assistance or, if it’s safe to do, change them to a CCB or BB for ~ 1 month and then repeat screening.
Refer to Endocrinology if patient has:
- Any worrisome features on imaging (>10HU, >4cm, irregular, >50% washout, calcifications, growth >1cm)
- A functioning adenoma
- Their tests are indeterminate (especially patients on SNRIs/TCAs whose metanephrine/catecholamine screen might be falsely + or a patient on ACE-I/ARB/aldactone that you feel might be interfering with the tests).
Long term monitoring: (there are no set guidelines)
- Repeat imaging: 6mo, 12mo, then 24mo and if no changes, you can stop imaging.
- Repeat labs (cortisol, metanephrines/catecholamines) yearly x 4 years (Dr. Abramowitz is confident you can stop after 2 years if imaging and hormonal studies are all negative/stable).
To Summarize (per Dr. William Young, NEJM):