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Clinical chemistry 

Adrenal Gland

Hyperaldosteronism

 

Author: Renu Virk, M.D. (see Authors page)

Revised: 21 September 2012, last major update - February 2010

Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.

 

Definition

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● Disorder caused by excess secretion of aldosterone

● See also Adrenal Gland chapter

 

Terminology

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Primary hyperaldosteronism: cause is in the adrenal gland

Secondary hyperaldosteronism: cause is extra-adrenal

Tertiary hyperaldosteronism: cause is renal juxtaglomerular cells

 

Etiology

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Synthesis pathway                   Renin-angiotensin-

                                                aldosterone axis

 

Primary hyperaldosteronism causes:

Idiopathic adrenal hyperplasia: most common cause

Conn’s syndrome: aldosterone producing adrenal adenoma, rarely adrenal carcinoma

 

Secondary hyperaldosteronism causes:

● Increased levels of plasma renin from non-adrenal pathology, including congestive heart failure, pregnancy (due to estrogen), decreased renal perfusion (renal arterial stenosis, nephrosclerosis), hypoalbuminemia, ovarian tumor, hyperthyroidism

 

Tertiary hyperaldosteronism (Bartter’s syndrome):

● Hypertrophy and hyperplasia of renal juxtaglomerular cells, causing elevated plasma renin, angiotensin II and aldosterone, hypokalemic alkalosis but no hypertension; some cases are autosomal recessive; infants or adults (eMedicine, Wikipedia)

 

Glucocorticoid suppressible hyperaldosteronism:

● Also called familial hyperaldosteronism type I

● Rare, familial; due to mutation which causes developmental derangement of cortical zonation, with hybrid cells between glomerulosa and fasciculata that are under the influence of ACTH, but can be suppressed by dexamethasone

 

Familial cases

● Early onset hypertension and severe target organ damage

 

Laboratory findings

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● High serum sodium, low serum potassium, metabolic alkalosis

 

Diagnostic tests for primary hyperaldosteronism

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● Nonsuppressible aldosterone excretion with normal cortisol excretion, low plasma renin

 

Screening tests:

● Preferred screening test is Ratio of plasma aldosterone concentration (PAC, in ng/dl) to plasma renin activity (PRA, in ng/ml/hr)

● Ratio >30 is strongly suggestive of primary hyperaldosteronism

 

Confirmatory test:

● Serum aldosterone level, urine aldosterone levels, saline suppression test

 

Diagnostic algorithms

 

Clinical

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● Causes urinary loss of potassium and hypokalemia, sodium retention and hypertension

● May cause up to 14% of cases of refractory hypertension (Arq Bras Cardiol 2009;92:39)

● Hypokalemia (present in 63%, Dtsch Arztebl Int 2009;106:305) causes weakness, paresthesias, visual disturbances, tetany

● Sodium retention causes volume overload which suppresses the renin-angiotensin system and reduces plasma renin activity; volume overload causes polyuria, polydipsia, nocturia, hypertension, alkalosis, hypernatremia

 

Treatment

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● Surgery for adenoma; patients with bilateral adrenal hyperplasia need spironolactone or other antihypertensive drugs

 

Case reports

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● 28 year old woman with adrenal adenoma also causing hypocalcemia (J Korean Med Sci 2009;24:1220)

 

Additional references

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eMedicine #1#2 (children)

 

End of Clinical Chemistry > Adrenal Gland > Hyperaldosteronism

 

 

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