Editing Adrenal: Hyperaldosteronism (section)

== Primary hyperaldosteronism ==

=== Diagnosis and Evaluation ===

* '''Indications for primary hyperaldosteronism screening (9):'''
*# '''Unexplained hypokalemia (spontaneous or diuretic induced)'''
*# '''Hypertension with hypokalemia'''
*# '''Adrenal incidentaloma with hypertension'''
*# '''Resistant hypertension (3 or more oral agents with poor control)'''
*# '''Early-onset hypertension (<20 years) or stroke (<50 years)'''
*# '''Severe hypertension (≥160/≥110)'''
*# '''Whenever considering secondary causes of hypertension (i.e., pheochromocytoma or renovascular disease)'''
*# '''Evidence of target organ damage disproportionate to degree of hypertension'''
*# '''Hypertension with family history of primary aldosteronism'''
** Primary hyperaldosteronism may be unmasked by diuretic-induced hypokalemia. The diagnosis is confirmed if 24-hour urinary aldosterone levels remain elevated after sodium loading (see below). After confirming diagnosis, a CT scan is done to localized the tumour.

==== Labs ====

* '''Aldosterone-to-renin ratio (ARR)'''
** '''Used to screen for primary hyperaldosteronism.'''
** Involves measuring a morning (between 8-10 AM) plasma aldosterone concentration (PAC) and plasma renin activity (PRA).
** An ARR of > 20 (some suggest > 30) along with a concomitant aldosterone concentration > 15 ng/mL is indicative of hyperaldosteronism; standard thresholds have not been established due to laboratory variability.
* '''Before screening is initiated, hypokalemia should be corrected and all contraindicated medications discontinued'''.
** Although patients can continue the majority of anti-hypertensive agents during screening, '''potassium-sparing diuretics such as amiloride or triamterene, and especially mineralocorticoid receptor blockers such as spironolactone and eplerenone, alter the RAAS and will affect test results. These medications should be stopped approximately 6 weeks before testing.'''
* 50-70% of patients with a positive screening test will be diagnosed with primary aldosteronism following confirmatory testing. '''The majority of confirmatory tests evaluate the suppression of aldosterone after sodium loading.'''
** The underlying theory behind the sodium loading tests is that loading will decrease plasma renin and aldosterone production in patients without autonomous aldosterone secretion.
*** The oral sodium loading test is conducted by administering a high-sodium diet for 3 days, followed by 24-hour urine measurements of aldosterone, sodium, and creatinine.

==== Imaging ====

* '''Cross-sectional abdominal imaging''' should be performed in all patients with primary aldosteronism who are potential surgical candidates.
* '''Radiographic characteristics of aldosterone-producing adenomas include the presence of a unilateral low-density non-enhancing lesion of < 10 Hounsfield units'''
** '''Lateralization of adrenal aldosterone-producing disease cannot be based on CT alone. Patients with confirmed primary aldosteronism should undergo adrenal vein sampling to establish lateralization when adrenalectomy is being considered. Exceptions include:'''
**# '''Patients <40 years with a clear unilateral adrenal adenoma and normal contralateral adrenal gland on imaging'''
**# '''Patients suspected of having an ACC'''

==== Genetic screening ====

* '''Given the rarity of familial primary hyperaldosteronism, genetic screening should not be performed in all patients'''. However, patients with a family history of primary aldosteronism, early age of onset (<20 years), or with a family history of cerebral vascular accidents at a young age should be considered for genetic testing