Hyperaldosteronism

Question 1

primary aldosteronism

Answer 1

Normokalemia is more common than hypokalemia in patients diagnosed with primary aldosteronism.

Question 2

glucocorticoid-remediable aldosteronism (GRA)

Answer 2

normokalemia is the rule in patients with the rare genetic disorde

CYP11B1/CYP11B2 chimeric gene

hypersecretion of aldosterone can be reversed with physiologic doses of glucocorticoid

Question 3

Hperaldostronism

Initial approch

Answer 3

plasma aldosterone to renin ratio (PAC/PRA) and an increased plasma aldosterone concentration (PAC) are both required for the diagnosis of primary aldosteronism.

• Primary aldosteronism should be suspected when PRA is suppressed (or PRC is undetectable) and PAC is increased as described below.
• Secondary hyperaldosteronism (eg, renovascular disease) should be considered when both the PRA (or PRC) and PAC are increased and the PAC/PRA ratio is <10 (eg, renovascular disease).
• An alternate source of mineralocorticoid receptor stimulation (eg, hypercortisolism, licorice root ingestion) should be considered when both the PRA (or PRC) and PAC are suppressed. (See ‘Nonaldosterone mineralocorticoid excess’ below.)

Question 4

Protocol

Answer 4

The definition of an abnormal PAC/PRA ratio is laboratory dependent. In general, PRA and PRC are undetectable in patients with primary aldosteronism. Also, in most patients with primary aldosteronism, the PAC is >15 ng/dL (416 pmol/L); the net effect is a PAC/PRA ratio greater than 20 (depending upon the laboratory normals) [14]. Although we consider a PAC/PRA ratio >20 to be suggestive of primary aldosteronism, others use a cutoff criteria of 30

Question 5

Confirmation

Answer 5

The exception to the requirement for confirmatory testing is the patient with spontaneous hypokalemia, undetectable PRA or PRC, and a PAC >30 ng/dL

However, aldosterone suppression testing is usually needed and it can be performed with orally administered sodium chloride and measurement of urine aldosterone excretion or with intravenous sodium chloride loading and measurement of PAC [17,26]. The 2008 Endocrine Society Guidelines suggest fludrocortisone suppression or captopril challenge tests as two additional alternative confirmatory tests

Question 6

Oral sodium

Answer 6

Need to consume to achieve a 5000 mg sodium diet.

In circumstances of high sodium dietary intolerance, patients can be given oral sodium chloride tablets (eg, two 1 g sodium chloride tablets taken three times daily with food will provide approximately 90 meq of sodium).

On the third day of the high sodium diet, serum electrolytes are measured and a 24-hour urine specimen is collected for measurement of aldosterone, sodium, and creatinine. The 24-hour urine sodium excretion should exceed 200 meq to document adequate sodium loading. Urine aldosterone excretion >12 mcg/24 hours (33nmol/day) in this setting is consistent with hyperaldosteronism

Question 7

Saline infusion test —

Answer 7

Saline infusion test — An alternate method to suppress endogenous aldosterone production is by the intravenous administration of two liters of isotonic saline over four hours (from 8 AM to noon) while the patient is recumbent [26]. The PAC will fall below 5 ng/dL (139 pmol/L) in normal subjects, whereas values above 10 ng/dL (277 pmol/L) are consistent with primary aldosteronism