APPARENT MINERALOCORTICOID EXCESS & TREATMENT
Definition: What is "Apparent mineralocorticoid excess"?
Apparent mineralocorticoid excess (AME) is a potentially fatal genetic disorder & autosomal recessive cause of hypokalaemia, prenatal & postnatal growth failure, undetectable levels of aldosterone & renin & hypertension, which responds to treatments using glucocorticoid. Apparent mineralocorticoid excess is an extremely rare disorder, accounting to only 60 patients recorded for the past 20 years. Apparent mineralocorticoid excess is a result of mutations of the HSD11B2 gene, which is responsible for encoding the kidney isozyme "11B-hydroxysteroid dehydrogenase". This isozyme inactivates the circulating cortisol to the less-active metabolite cortisone, which leads to an elevated amount of cortisol in the kidney. Note that high concentrations of cortisol could activate the "mineralocorticoid receptor", which leads to an aldosterone-like effect in the patient's kidneys. This occurrence causes hypernatremia, hypokalemia & hypertension. Apparent mineralocorticoid excess can also be caused by licorice ingestion, which blocks 11-hydroxysteroid dehydrogenase & increase cortisol activity. Early & aggressive treatment of Apparent mineralocorticoid excess can prevent & improve the mortality & morbidity of end-organ damage rates. Diagnosis is made by DNA & hormonal analysis.
Symptoms & Signs
Apparent mineralocorticoid excess can be seen after birth with low birth weight & postnatal failure to thrive. Most patients of AME experience hypertension, polydipsia & persistent polyuria. AME is characterized by hyporeninemia, hypokalemic alkalosis & undetectable serum concentrations of "aldosterone". Majority of Apparent mineralocorticoid excess patients develop hypertension even at a young age. End-organ damages can also occur in the heart, retina, kidney or central nervous system.
Treatment: How to Treat "Apparent mineralocorticoid excess"?
Treatment for Apparent mineralocorticoid excess is primarily focused in correcting hypertension & hypokalemia. Doctors recommend the MR receptor antagonist spironolactone as medication to protect receptors against excessive mineralocorticoid. Reduction in supplemental potassium & dietary sodium is usually instructed. AME patients with "nephrocalcinosis" may require thiazide diuretic. Anti-hypertensive drugs, such as amiloride & thiazides may be helpful as the disease progresses.