Hypoaldosteronism pathophysiology: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
No edit summary
No edit summary
Line 4: Line 4:


==Overview==
==Overview==
Hypoaldosteronism is defined as decreased levels of the hormone aldosterone or a resistance of the target tissue to the actions of aldosterone. Hypoaldosteronism from decreased production is seen in conditions such as congenital isolated hypoaldosteronism, primary adrenal insufficiency, diabetic nephropathy, critical illness, and drugs such as ACE inhibitors, NSAIDs and calcineurin inhibitors. Resistance of the target tissue to the actions of aldosterone is seen with mineralocorticoid receptor defects (seen in pseudohypoaldosteronism) and with drugs such as potassium-sparing diuretics and trimethoprim. Hypoaldosteronism results in reduced reabsorption of sodium in the principal cells of cortical collecting tubules (CCT). This leads to decreased excretion of potassium (hyperkalemia) and mild non-anion gap metabolic acidosis. On gross pathology, adrenal glands may be irregularly shrunken or hyperplastic.
Hypoaldosteronism is defined as decreased levels of the [[hormone]] [[aldosterone]] or a [[resistance]] of the target tissue to the actions of [[aldosterone]]. Hypoaldosteronism from decreased production is seen in conditions such as congenital isolated hypoaldosteronism, [[Primary adrenal insufficiency|primary adrenal insufficiency,]] [[diabetic nephropathy]], [[critical illness]], and [[drugs]] such as [[ACE inhibitor|ACE inhibitors]], [[NSAIDs]] and [[Calcineurin inhibitor|calcineurin inhibitors]]. [[Resistance]] of the target tissue to the actions of [[aldosterone]] is seen with [[mineralocorticoid receptor]] defects (seen in [[pseudohypoaldosteronism]]) and with [[drugs]] such as [[potassium-sparing diuretics]] and [[trimethoprim]]. Hypoaldosteronism results in reduced reabsorption of [[sodium]] in the [[principal cells]] of [[Cortical collecting duct|cortical collecting tubules]] (CCT). This leads to decreased excretion of [[potassium]] ([[hyperkalemia]]) and mild non-anion gap [[metabolic acidosis]]. On gross pathology, [[adrenal glands]] may be irregularly shrunken or hyperplastic.


==Pathophysiology==
==Pathophysiology==
Line 25: Line 25:


===Pathogenesis===
===Pathogenesis===
*Hypoaldosteronism is defined as decreased levels of the [[hormone]] [[aldosterone]] or a resistance of the target tissue to the actions of aldosterone. Hypoaldosteronism can be due to:<ref name="pmid8015573">{{cite journal |vauthors=White PC |title=Disorders of aldosterone biosynthesis and action |journal=N. Engl. J. Med. |volume=331 |issue=4 |pages=250–8 |year=1994 |pmid=8015573 |doi=10.1056/NEJM199407283310408 |url=}}</ref>
*Hypoaldosteronism is defined as decreased levels of the [[hormone]] [[aldosterone]] or a resistance of the target tissue to the actions of [[aldosterone]]. Hypoaldosteronism can be due to:<ref name="pmid8015573">{{cite journal |vauthors=White PC |title=Disorders of aldosterone biosynthesis and action |journal=N. Engl. J. Med. |volume=331 |issue=4 |pages=250–8 |year=1994 |pmid=8015573 |doi=10.1056/NEJM199407283310408 |url=}}</ref>
** '''Aldosterone deficiency''': The deficiency in aldosterone can be due to congenital isolated hypoaldosteronism, primary adrenal insufficiency, diabetic nephropathy, critical illness, and drugs such as ACE inhibitors, NSAID and calcineurin inhibitors.
** '''Aldosterone deficiency''': The deficiency in [[aldosterone]] can be due to congenital isolated hypoaldosteronism, [[primary adrenal insufficiency]], [[diabetic nephropathy]], [[critical illness]], and [[drugs]] such as [[ACE inhibitor|ACE inhibitors]], [[NSAIDs|NSAID]] and [[Calcineurin inhibitor|calcineurin inhibitors]].
** '''Aldosterone resistance''': In aldosterone resistance, the level of aldosterone is normal but there is decreased response of the target tissue to the actions of aldosterone. Aldosterone resistance is seen with mineralocorticoid receptor defects (seen in pseudohypoaldosteronism) and with drugs such as potassium-sparing diuretics and trimethoprim.
** '''Aldosterone resistance''': In [[aldosterone]] resistance, the level of [[aldosterone]] is normal but there is decreased response of the target tissue to the actions of [[aldosterone]]. [[Aldosterone]] resistance is seen with [[mineralocorticoid receptor]] defects (seen in [[pseudohypoaldosteronism]]) and with [[drugs]] such as [[Potassium-sparing diuretic|potassium-sparing diuretics]] and trimethoprim.


*Hypoaldosteronism results in reduced reabsorption of sodium in the principal cells of cortical collecting tubules (CCT).  This leads to decreased excretion of potassium and mild non-anion gap metabolic acidosis.
*Hypoaldosteronism results in reduced [[reabsorption]] of [[sodium]] in the [[principal cells]] of [[Cortical collecting ducts|cortical collecting tubules]] (CCT).  This leads to decreased [[excretion]] of [[potassium]] and mild non-anion gap [[metabolic acidosis]].


=== Hyporeninemic Hypoaldosteronism===
=== Hyporeninemic Hypoaldosteronism===
* Hyporeninemic hypoaldosteronism is most commonly seen in patients with mild to moderate renal insufficiency and diabetic nephropathy:
* Hyporeninemic hypoaldosteronism is most commonly seen in patients with mild to moderate [[renal insufficiency]] and [[Diabetic nephropathy|diabetic nephropathy:]]
** In patients of renal insufficiency, atrophy of the juxtaglomerular apparatus (JGA) leads to decreased sensing of plasma sodium concentration and renal perfusion pressure.
** In patients of [[renal insufficiency]], [[atrophy]] of the [[juxtaglomerular apparatus]] (JGA) leads to decreased sensing of plasma [[sodium]] concentration and renal [[perfusion pressure]].
** With progression of the renal disease and atrophy of the juxtaglomerular apparatus (JGA) there may be inadequate renin production and release.
** With progression of the [[renal disease]] and [[atrophy]] of the [[juxtaglomerular apparatus]] (JGA) there may be inadequate [[renin]] production and release.
** A decrease in renin production and release leads to decreased angiotensin production, which eventually causes hypoaldosteronism .
** A decrease in [[renin]] production and release leads to decreased [[angiotensin]] production, which eventually causes hypoaldosteronism .
** Renal insufficiency may also cause decreased response of the principal cells in the cortical collecting tubule to aldosterone.
** [[Renal insufficiency]] may also cause decreased response of the [[principal cells]] in the [[cortical collecting tubule]] to [[aldosterone]].


===Hyperreninemic Hypoaldosteronism===
===Hyperreninemic Hypoaldosteronism===
* Hyperreninemic hypoaldosteronism also known as secondary isolated hypoaldosteronism is seen in patients with severe illness such as sepsis, malignancy, heart failure, adrenal dysfunction and liver cirrhosis.<ref name="pmid6291814">{{cite journal |vauthors=Kater CE, Biglieri EG, Brust N, Chang B, Hirai J |title=Regulation of the mineralocorticoid hormones in adrenocortical disorders with adrenocorticotropin excess |journal=Clin Exp Hypertens A |volume=4 |issue=9-10 |pages=1749–58 |year=1982 |pmid=6291814 |doi= |url=}}</ref><ref name="pmid6256154">{{cite journal |vauthors=Aguilera G, Fujita K, Catt KJ |title=Mechanisms of inhibition of aldosterone secretion by adrenocorticotropin |journal=Endocrinology |volume=108 |issue=2 |pages=522–8 |year=1981 |pmid=6256154 |doi=10.1210/endo-108-2-522 |url=}}</ref><ref name="pmid1851063">{{cite journal |vauthors=Singer DR, Shirley DG, Markandu ND, Miller MA, Buckley MG, Sugden AL, Sagnella GA, MacGregor GA |title=How important are suppression of aldosterone and stimulation of atrial natriuretic peptide secretion in the natriuretic response to an acute sodium load in man? |journal=Clin. Sci. |volume=80 |issue=4 |pages=293–9 |year=1991 |pmid=1851063 |doi= |url=}}</ref>
* Hyperreninemic hypoaldosteronism also known as secondary isolated hypoaldosteronism is seen in [[patients]] with severe [[illness]] such as [[sepsis]], [[malignancy]], [[heart failure]], adrenal dysfunction and [[liver cirrhosis]].<ref name="pmid6291814">{{cite journal |vauthors=Kater CE, Biglieri EG, Brust N, Chang B, Hirai J |title=Regulation of the mineralocorticoid hormones in adrenocortical disorders with adrenocorticotropin excess |journal=Clin Exp Hypertens A |volume=4 |issue=9-10 |pages=1749–58 |year=1982 |pmid=6291814 |doi= |url=}}</ref><ref name="pmid6256154">{{cite journal |vauthors=Aguilera G, Fujita K, Catt KJ |title=Mechanisms of inhibition of aldosterone secretion by adrenocorticotropin |journal=Endocrinology |volume=108 |issue=2 |pages=522–8 |year=1981 |pmid=6256154 |doi=10.1210/endo-108-2-522 |url=}}</ref><ref name="pmid1851063">{{cite journal |vauthors=Singer DR, Shirley DG, Markandu ND, Miller MA, Buckley MG, Sugden AL, Sagnella GA, MacGregor GA |title=How important are suppression of aldosterone and stimulation of atrial natriuretic peptide secretion in the natriuretic response to an acute sodium load in man? |journal=Clin. Sci. |volume=80 |issue=4 |pages=293–9 |year=1991 |pmid=1851063 |doi= |url=}}</ref>
** During these [[Stress (medicine)|stress]] inducing conditions, increased levels of ACTH and cortisol are seen.  
** During these [[Stress (medicine)|stress]] inducing conditions, increased levels of [[Adrenocorticotropic hormone|ACTH]] and [[cortisol]] are seen.  
** Under normal conditions, continuous ACTH secretion for greater than 96 hours leads to suppression of aldosterone synthase activity.
** Under normal conditions, continuous [[Adrenocorticotropic hormone|ACTH]] secretion for greater than 96 hours leads to suppression of [[aldosterone synthase]] activity.
** Chronically ill patients with prolonged ACTH secretion (>96 hours) have impaired aldosterone synthase activity and decreased levels of aldosterone.   
** Chronically ill patients with prolonged [[Adrenocorticotropic hormone|ACTH]] secretion (>96 hours) have impaired [[aldosterone synthase]] activity and decreased levels of [[aldosterone]].   
** In response, the kidneys via its neurohormonal regulation leads to increased levels of renin and hence the term hyperreninemic hypoaldosteronism.  
** In response, the [[kidneys]] via its neurohormonal regulation leads to increased levels of [[renin]] and hence the term hyperreninemic hypoaldosteronism.  
** In addition, cytokine release from chronic illness or increased levels of atrial natriuretic peptide (in patients with heart failure) also have an inhibitory effect on the zona glomerulosa of adrenal cortex.
** In addition, [[cytokine]] release from chronic illness or increased levels of [[atrial natriuretic peptide]] (in patients with [[heart failure]]) also have an [[inhibitory]] effect on the [[zona glomerulosa]] of [[adrenal cortex]].
* Hyperreninemic hypoaldosteronism is also seen in patients with adrenal dysfunction such as Addison's disease.  
* Hyperreninemic hypoaldosteronism is also seen in patients with adrenal dysfunction such as [[Addison's disease]].  
** Primary adrenal insufficiency or Addison's disease can be due to [[Adrenal gland|adrenal]] [[dysgenesis]], impaired [[steroidogenesis]], and [[Adrenal Gland|adrenal]] destruction.
** [[Primary adrenal insufficiency]] or [[Addison's disease]] can be due to [[Adrenal gland|adrenal]] [[dysgenesis]], impaired [[steroidogenesis]], and [[Adrenal Gland|adrenal]] destruction.
** In patients of primary adrenal insufficiency, the adrenal glands does not produce sufficient cortisol and aldosterone.
** In patients of [[primary adrenal insufficiency]], the [[adrenal glands]] does not produce sufficient [[cortisol]] and [[aldosterone]].
** The decrease in level of aldosterone leads to decreased absorption of sodium in the kidneys and increased retention of potassium. This in turn activates the juxtaglomerular apparatus (JGA) of the kidneys, which secretes renin in an attempt to normalise plasma sodium concentration and perfusion pressure. However, due to adrenal dysfunction the zona glomerulosa of adrenal cortex is unable to produce aldosterone and presents with hyperreninemic hypoaldosteronism.
** The decrease in level of [[aldosterone]] leads to decreased [[absorption]] of [[sodium]] in the [[kidneys]] and increased retention of [[potassium]]. This in turn activates the [[juxtaglomerular apparatus]] (JGA) of the [[kidneys]], which secretes [[renin]] in an attempt to normalise [[plasma]] [[sodium]] [[concentration]] and [[perfusion pressure]]. However, due to [[Adrenal gland|adrenal]] dysfunction the [[zona glomerulosa]] of [[adrenal cortex]] is unable to produce [[aldosterone]] and presents with hyperreninemic hypoaldosteronism.


===Isolated Hypoaldosteronism===
===Isolated Hypoaldosteronism===
*In isolated hypoaldosteronism, there is selective deficiency of aldosterone with normal cortisol production. Isolated hypoaldosteronism may result from dysfunction of zona glomerulosa or aldosterone synthase deficiency.  
*In isolated hypoaldosteronism, there is selective [[deficiency]] of [[aldosterone]] with normal [[cortisol]] production. Isolated hypoaldosteronism may result from dysfunction of [[zona glomerulosa]] or [[aldosterone synthase]] deficiency.  
** Aldosterone synthase is an enzyme involved in the synthesis of aldosterone. Patients with aldosterone synthase enzyme deficiency (type I and type II) results in defective conversion of deoxycorticosterone to aldosterone and subsequently abnormal levels of aldosterone.
** [[Aldosterone synthase]] is an [[enzyme]] involved in the [[synthesis]] of [[aldosterone]]. Patients with [[aldosterone synthase]] [[enzyme]] [[deficiency]] (type I and type II) results in defective conversion of [[deoxycorticosterone]] to [[aldosterone]] and subsequently abnormal levels of [[aldosterone]].
** Certain drugs such as heparin and nitric oxide have a direct suppressive effect on the zona glomerulosa of adrenal cortex which may lead to decrease production of aldosterone.
** Certain [[drugs]] such as [[heparin]] and [[nitric oxide]] have a direct suppressive effect on the [[zona glomerulosa]] of [[adrenal cortex]] which may lead to decrease production of [[aldosterone]].


===Postadrenalectomy Hypoaldosteronism===
===Postadrenalectomy Hypoaldosteronism===
Postadrenalectomy hypoaldosteronism is seen in patients with Conn syndrome who undergo surgery for tumor removal:<ref name="pmid7001091">{{cite journal |vauthors=Kawasaki T, Uezono K, Ueno M, Noda Y, Kumamoto K, Kawano Y, Ogata M, Fukiyama K, Omae T, Bartter FC |title=Influence of unilateral adrenalectomy on renin-angiotensin-aldosterone system in primary aldosteronism |journal=Jpn Heart J |volume=21 |issue=5 |pages=681–92 |year=1980 |pmid=7001091 |doi= |url=}}</ref><ref name="pmid19721021">{{cite journal |vauthors=Kempers MJ, Lenders JW, van Outheusden L, van der Wilt GJ, Schultze Kool LJ, Hermus AR, Deinum J |title=Systematic review: diagnostic procedures to differentiate unilateral from bilateral adrenal abnormality in primary aldosteronism |journal=Ann. Intern. Med. |volume=151 |issue=5 |pages=329–37 |year=2009 |pmid=19721021 |doi= |url=}}</ref><ref name="pmid20420801">{{cite journal |vauthors=Huang WT, Chau T, Wu ST, Lin SH |title=Prolonged hyperkalemia following unilateral adrenalectomy for primary hyperaldosteronism |journal=Clin. Nephrol. |volume=73 |issue=5 |pages=392–7 |year=2010 |pmid=20420801 |doi= |url=}}</ref><ref name="pmid9669438">{{cite journal |vauthors=Gadallah MF, Kayyas Y, Boules F |title=Reversible suppression of the renin-aldosterone axis after unilateral adrenalectomy for adrenal adenoma |journal=Am. J. Kidney Dis. |volume=32 |issue=1 |pages=160–3 |year=1998 |pmid=9669438 |doi= |url=}}</ref><ref name="pmid4287160">{{cite journal |vauthors=Biglieri EG, Slaton PE, Silen WS, Galante M, Forsham PH |title=Postoperative studies of adrenal function in primary aldosteronism |journal=J. Clin. Endocrinol. Metab. |volume=26 |issue=5 |pages=553–8 |year=1966 |pmid=4287160 |doi=10.1210/jcem-26-5-553 |url=}}</ref><ref name="pmid3902226">{{cite journal |vauthors=Groth H, Vetter W, Stimpel M, Greminger P, Tenschert W, Klaiber E, Vetter H |title=Adrenalectomy in primary aldosteronism: a long-term follow-up study |journal=Cardiology |volume=72 Suppl 1 |issue= |pages=107–16 |year=1985 |pmid=3902226 |doi= |url=}}</ref><ref name="pmid25604311">{{cite journal |vauthors=Yorke E, Stafford S, Holmes D, Sheth S, Melck A |title=Aldosterone deficiency after unilateral adrenalectomy for Conn's syndrome: a case report and literature review |journal=Int J Surg Case Rep |volume=7C |issue= |pages=141–4 |year=2015 |pmid=25604311 |pmc=4336421 |doi=10.1016/j.ijscr.2015.01.013 |url=}}</ref>
Postadrenalectomy hypoaldosteronism is seen in patients with [[Conn syndrome pathophysiology|Conn syndrome]] who undergo [[surgery]] for [[tumor]] removal:<ref name="pmid7001091">{{cite journal |vauthors=Kawasaki T, Uezono K, Ueno M, Noda Y, Kumamoto K, Kawano Y, Ogata M, Fukiyama K, Omae T, Bartter FC |title=Influence of unilateral adrenalectomy on renin-angiotensin-aldosterone system in primary aldosteronism |journal=Jpn Heart J |volume=21 |issue=5 |pages=681–92 |year=1980 |pmid=7001091 |doi= |url=}}</ref><ref name="pmid19721021">{{cite journal |vauthors=Kempers MJ, Lenders JW, van Outheusden L, van der Wilt GJ, Schultze Kool LJ, Hermus AR, Deinum J |title=Systematic review: diagnostic procedures to differentiate unilateral from bilateral adrenal abnormality in primary aldosteronism |journal=Ann. Intern. Med. |volume=151 |issue=5 |pages=329–37 |year=2009 |pmid=19721021 |doi= |url=}}</ref><ref name="pmid20420801">{{cite journal |vauthors=Huang WT, Chau T, Wu ST, Lin SH |title=Prolonged hyperkalemia following unilateral adrenalectomy for primary hyperaldosteronism |journal=Clin. Nephrol. |volume=73 |issue=5 |pages=392–7 |year=2010 |pmid=20420801 |doi= |url=}}</ref><ref name="pmid9669438">{{cite journal |vauthors=Gadallah MF, Kayyas Y, Boules F |title=Reversible suppression of the renin-aldosterone axis after unilateral adrenalectomy for adrenal adenoma |journal=Am. J. Kidney Dis. |volume=32 |issue=1 |pages=160–3 |year=1998 |pmid=9669438 |doi= |url=}}</ref><ref name="pmid4287160">{{cite journal |vauthors=Biglieri EG, Slaton PE, Silen WS, Galante M, Forsham PH |title=Postoperative studies of adrenal function in primary aldosteronism |journal=J. Clin. Endocrinol. Metab. |volume=26 |issue=5 |pages=553–8 |year=1966 |pmid=4287160 |doi=10.1210/jcem-26-5-553 |url=}}</ref><ref name="pmid3902226">{{cite journal |vauthors=Groth H, Vetter W, Stimpel M, Greminger P, Tenschert W, Klaiber E, Vetter H |title=Adrenalectomy in primary aldosteronism: a long-term follow-up study |journal=Cardiology |volume=72 Suppl 1 |issue= |pages=107–16 |year=1985 |pmid=3902226 |doi= |url=}}</ref><ref name="pmid25604311">{{cite journal |vauthors=Yorke E, Stafford S, Holmes D, Sheth S, Melck A |title=Aldosterone deficiency after unilateral adrenalectomy for Conn's syndrome: a case report and literature review |journal=Int J Surg Case Rep |volume=7C |issue= |pages=141–4 |year=2015 |pmid=25604311 |pmc=4336421 |doi=10.1016/j.ijscr.2015.01.013 |url=}}</ref>
* Conn syndrome is most often unilateral and leads to excessive production of aldosterone from the affected adrenal gland.  
* [[Conn syndrome pathophysiology|Conn syndrome]] is most often unilateral and leads to excessive production of [[aldosterone]] from the affected [[adrenal gland]].  
* Excessive production of aldosterone causes hypertension and suppression of renin angiotensin aldosterone system (RAAS).
* Excessive production of [[aldosterone]] causes [[hypertension]] and suppression of [[renin angiotensin aldosterone system]] ([[RAAS]]).
* Patients of Conn syndrome who are treated with spironolactone and later undergo surgery for tumor removal may develop hypoaldosteronism.
* Patients of [[Conn syndrome pathophysiology|Conn syndrome]] who are treated with [[spironolactone]] and later undergo [[surgery]] for [[tumor]] removal may develop hypoaldosteronism.
* Patients of Conn syndrome have increased levels of aldosterone and decreased plasma renin activity (from suppressed RAAS) which leads to chronic suppression of contralateral zona glomerulosa.
* Patients of [[Conn syndrome pathophysiology|Conn syndrome]] have increased levels of [[aldosterone]] and decreased [[plasma renin activity]] (from suppressed [[RAAS]]) which leads to chronic suppression of contralateral [[zona glomerulosa]].
* On surgical removal of aldosterone producing tumor, there is sudden decline in circulating aldosterone which leads to hypoaldosteronism.
* On surgical removal of aldosterone producing [[tumor]], there is sudden decline in circulating [[aldosterone]] which leads to hypoaldosteronism.


===Mineralocorticoid Resistance===
===Mineralocorticoid Resistance===
Mineralocorticoid resistance is characterized by a decrease in response to the hormone aldosterone. In mineralocorticoid resistance the level of aldosterone may be normal or supranormal. It is due to this reason mineralocorticoid resistance is also known as pseudohypoaldosteronism. Mineralocorticoid resistance can be further categorized into:<ref name="pmid13545877">{{cite journal |vauthors=CHEEK DB, PERRY JW |title=A salt wasting syndrome in infancy |journal=Arch. Dis. Child. |volume=33 |issue=169 |pages=252–6 |year=1958 |pmid=13545877 |pmc=2012226 |doi= |url=}}</ref><ref name="pmid11498583">{{cite journal |vauthors=Wilson FH, Disse-Nicodème S, Choate KA, Ishikawa K, Nelson-Williams C, Desitter I, Gunel M, Milford DV, Lipkin GW, Achard JM, Feely MP, Dussol B, Berland Y, Unwin RJ, Mayan H, Simon DB, Farfel Z, Jeunemaitre X, Lifton RP |title=Human hypertension caused by mutations in WNK kinases |journal=Science |volume=293 |issue=5532 |pages=1107–12 |year=2001 |pmid=11498583 |doi=10.1126/science.1062844 |url=}}</ref><ref name="pmid23453970">{{cite journal |vauthors=Wakabayashi M, Mori T, Isobe K, Sohara E, Susa K, Araki Y, Chiga M, Kikuchi E, Nomura N, Mori Y, Matsuo H, Murata T, Nomura S, Asano T, Kawaguchi H, Nonoyama S, Rai T, Sasaki S, Uchida S |title=Impaired KLHL3-mediated ubiquitination of WNK4 causes human hypertension |journal=Cell Rep |volume=3 |issue=3 |pages=858–68 |year=2013 |pmid=23453970 |doi=10.1016/j.celrep.2013.02.024 |url=}}</ref>
Mineralocorticoid resistance is characterized by a decrease in response to the hormone [[aldosterone]]. In mineralocorticoid resistance the level of [[aldosterone]] may be normal or supranormal. It is due to this reason mineralocorticoid resistance is also known as [[pseudohypoaldosteronism]]. Mineralocorticoid resistance can be further categorized into:<ref name="pmid13545877">{{cite journal |vauthors=CHEEK DB, PERRY JW |title=A salt wasting syndrome in infancy |journal=Arch. Dis. Child. |volume=33 |issue=169 |pages=252–6 |year=1958 |pmid=13545877 |pmc=2012226 |doi= |url=}}</ref><ref name="pmid11498583">{{cite journal |vauthors=Wilson FH, Disse-Nicodème S, Choate KA, Ishikawa K, Nelson-Williams C, Desitter I, Gunel M, Milford DV, Lipkin GW, Achard JM, Feely MP, Dussol B, Berland Y, Unwin RJ, Mayan H, Simon DB, Farfel Z, Jeunemaitre X, Lifton RP |title=Human hypertension caused by mutations in WNK kinases |journal=Science |volume=293 |issue=5532 |pages=1107–12 |year=2001 |pmid=11498583 |doi=10.1126/science.1062844 |url=}}</ref><ref name="pmid23453970">{{cite journal |vauthors=Wakabayashi M, Mori T, Isobe K, Sohara E, Susa K, Araki Y, Chiga M, Kikuchi E, Nomura N, Mori Y, Matsuo H, Murata T, Nomura S, Asano T, Kawaguchi H, Nonoyama S, Rai T, Sasaki S, Uchida S |title=Impaired KLHL3-mediated ubiquitination of WNK4 causes human hypertension |journal=Cell Rep |volume=3 |issue=3 |pages=858–68 |year=2013 |pmid=23453970 |doi=10.1016/j.celrep.2013.02.024 |url=}}</ref>
* '''Pseudohypoaldosteronism type I''':  
* '''Pseudohypoaldosteronism type I''':  
** The decrease in response to aldosterone is due to heterozygous or homozygous inactivating mutations in the mineralocorticoid receptor. These patients are also resistant to mineralocorticoid therapy.
** The decrease in response to aldosterone is due to heterozygous or homozygous inactivating mutations in the [[mineralocorticoid receptor]]. These patients are also resistant to mineralocorticoid therapy.
* '''Pseudohypoaldosteronism Type II''':  
* '''Pseudohypoaldosteronism Type II''':  
** This is an extremely rare disorder. It is speculated that these patients have mutations in the genes encoding proteins of the serine threonine kinase family (WKNK1 or WNK4 kinases). Pseudohypoaldosteronism Type II  is characterized by low or low-normal plasma renin activity and aldosterone concentrations, leading to hyperkalemia and metabolic acidosis with normal renal function. Pseudohypoaldosteronism type II is also known as Gordon’s syndrome.
** This is an extremely rare disorder. It is speculated that these patients have mutations in the genes encoding proteins of the serine threonine [[kinase]] family (WKNK1 or WNK4 kinases). Pseudohypoaldosteronism Type II  is characterized by low or low-normal [[plasma renin activity]] and [[aldosterone]] concentrations, leading to [[hyperkalemia]] and [[metabolic acidosis]] with normal [[renal]] function. Pseudohypoaldosteronism type II is also known as Gordon’s syndrome.
* '''Pseudohypoaldosteronism type III''':  
* '''Pseudohypoaldosteronism type III''':  
** This condition presents with transient mineralocorticoid resistance. Pseudohypoaldosteronism type III is seen in patients with underlying renal conditions with decreased GFR. The exact cause is unknown but is thought to be related to increased levels of TGF-β.
** This condition presents with [[transient]] mineralocorticoid resistance. Pseudohypoaldosteronism type III is seen in patients with underlying [[renal]] conditions with decreased [[GFR]]. The exact cause is unknown but is thought to be related to increased levels of [[TGF beta|TGF]]-β.


==Genetics==
==Genetics==
*Genes involved in the pathogenesis of hypoaldosteronism include mutation in CYP11B2 gene and NR3C2 gene.
*[[Genes]] involved in the [[pathogenesis]] of hypoaldosteronism include [[mutation]] in [[CYP11B2]] gene and NR3C2 gene.
*'''CYP11B2 gene''' is located on chromosome 8q24.
*'''CYP11B2 gene''' is located on chromosome 8q24.
**Mutation in CYP11B2 gene is transmitted in autosomal recessive pattern.
**[[Mutation]] in [[CYP11B2]] gene is transmitted in [[autosomal recessive]] pattern.
**The CYP11B2 gene encodes for the enzyme aldosterone synthase (previously known as corticosterone methyloxidase).  
**The [[CYP11B2]] gene encodes for the [[enzyme]] [[aldosterone synthase]] (previously known as corticosterone methyloxidase).  
**Aldosterone synthase catalyses the conversion of 11 deoxycorticosterone to aldosterone. The following flowchart depicts the various steps carried out by the enzyme aldosterone synthase:  
**[[Aldosterone synthase]] catalyses the conversion of 11 deoxycorticosterone to [[aldosterone]]. The following flowchart depicts the various steps carried out by the [[enzyme]] [[aldosterone synthase]]:  




Line 91: Line 91:




*Mutations in CYP11B2 can lead to:
*Mutations in [[CYP11B2]] can lead to:
**Type 1 aldosterone synthase deficiency: Patients have normal to decreased levels of 18-hydroxycorticosterone and undetectable levels of aldosterone.
**Type 1 [[aldosterone synthase]] deficiency: Patients have normal to decreased levels of 18-hydroxycorticosterone and undetectable levels of [[aldosterone]].
**Type 2 aldosterone synthase deficiency: Patients have increased levels of 18-hydroxycorticosterone and normal to decreased levels of aldosterone.
**Type 2 [[aldosterone synthase]] deficiency: Patients have increased levels of 18-hydroxycorticosterone and normal to decreased levels of [[aldosterone]].
**Aldosterone synthase is a member of the cytochrome P450 family of enzymes.
**[[Aldosterone synthase]] is a member of the [[cytochrome P450]] family of [[enzymes]].


*The other gene associated with hypoaldosteronism is '''NR3C2 gene.'''
*The other gene associated with hypoaldosteronism is '''NR3C2 gene.'''
**NR3C2 gene is located on chromosome 4q31.1-31.2; which is the long (q) arm of chromosome 4 at position 31.1-31.2
**NR3C2 [[gene]] is located on [[chromosome]] 4q31.1-31.2; which is the long (q) arm of [[chromosome 4]] at position 31.1-31.2
**NR3C2 gene encodes for mineralocorticoid receptor.
**NR3C2 [[gene]] encodes for [[mineralocorticoid receptor]].
**Mutation in NR3C2 gene can be transmitted in autosomal recessive or autosomal dominant pattern.
**[[Mutation]] in NR3C2 [[gene]] can be transmitted in autosomal recessive or autosomal dominant pattern.
**Mutated NR3C2 gene leads to defective mineralocorticoid receptor and presents with resistance to the actions of aldosterone.
**[[Mutated]] NR3C2 [[gene]] leads to defective [[mineralocorticoid receptor]] and presents with [[resistance]] to the actions of [[aldosterone]].


==Associated Conditions==
==Associated Conditions==

Revision as of 20:34, 30 August 2017

Hypoaldosteronism Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Hypoaldosteronism from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Criteria

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X Ray

CT

MRI

Echocardiography or Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Hypoaldosteronism pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Hypoaldosteronism pathophysiology

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Hypoaldosteronism pathophysiology

CDC on Hypoaldosteronism pathophysiology

Hypoaldosteronism pathophysiology in the news

Blogs on Hypoaldosteronism pathophysiology

Directions to Hospitals Treating Hypoaldosteronism

Risk calculators and risk factors for Hypoaldosteronism pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Akshun Kalia M.B.B.S.[2]

Overview

Hypoaldosteronism is defined as decreased levels of the hormone aldosterone or a resistance of the target tissue to the actions of aldosterone. Hypoaldosteronism from decreased production is seen in conditions such as congenital isolated hypoaldosteronism, primary adrenal insufficiency, diabetic nephropathy, critical illness, and drugs such as ACE inhibitors, NSAIDs and calcineurin inhibitors. Resistance of the target tissue to the actions of aldosterone is seen with mineralocorticoid receptor defects (seen in pseudohypoaldosteronism) and with drugs such as potassium-sparing diuretics and trimethoprim. Hypoaldosteronism results in reduced reabsorption of sodium in the principal cells of cortical collecting tubules (CCT). This leads to decreased excretion of potassium (hyperkalemia) and mild non-anion gap metabolic acidosis. On gross pathology, adrenal glands may be irregularly shrunken or hyperplastic.

Pathophysiology

Physiology


Source:By A. Rad (me) (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons


Pathogenesis

Hyporeninemic Hypoaldosteronism

Hyperreninemic Hypoaldosteronism

Isolated Hypoaldosteronism

Postadrenalectomy Hypoaldosteronism

Postadrenalectomy hypoaldosteronism is seen in patients with Conn syndrome who undergo surgery for tumor removal:[5][6][7][8][9][10][11]

Mineralocorticoid Resistance

Mineralocorticoid resistance is characterized by a decrease in response to the hormone aldosterone. In mineralocorticoid resistance the level of aldosterone may be normal or supranormal. It is due to this reason mineralocorticoid resistance is also known as pseudohypoaldosteronism. Mineralocorticoid resistance can be further categorized into:[12][13][14]

  • Pseudohypoaldosteronism type I:
    • The decrease in response to aldosterone is due to heterozygous or homozygous inactivating mutations in the mineralocorticoid receptor. These patients are also resistant to mineralocorticoid therapy.
  • Pseudohypoaldosteronism Type II:
    • This is an extremely rare disorder. It is speculated that these patients have mutations in the genes encoding proteins of the serine threonine kinase family (WKNK1 or WNK4 kinases). Pseudohypoaldosteronism Type II is characterized by low or low-normal plasma renin activity and aldosterone concentrations, leading to hyperkalemia and metabolic acidosis with normal renal function. Pseudohypoaldosteronism type II is also known as Gordon’s syndrome.
  • Pseudohypoaldosteronism type III:
    • This condition presents with transient mineralocorticoid resistance. Pseudohypoaldosteronism type III is seen in patients with underlying renal conditions with decreased GFR. The exact cause is unknown but is thought to be related to increased levels of TGF-β.

Genetics


 
 
 
11 Deoxycorticosterone
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corticosterone
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
18 Hydroxycorticosterone
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Aldosterone
 
 
 


Associated Conditions

  • Sickle cell disease
  • Analgesic nephropathy
  • Lead nephropathy
  • Chronic pyelonephritis
  • Obstructive nephropathy
  • Diabetes and renal insufficiency
  • Nonsteroidal anti-inflammatory drugs
  • Calcineurin inhibitors
  • Vitiligo
  • Premature ovarian failure
  • Pernicious anemia
  • Myasthenia gravis
  • Chronic candidiasis
  • Sjögren syndrome
  • Chronic active hepatitis
  • Hypothyroidism
  • Graves hyperthyroidism
  • Adrenoleukodystrophy

Gross Pathology

  • On gross pathology, adrenal glands in hypoaldosteronism can either be:
    • Irregularly shrunken, or
    • Hyperplastic
Image courtesy: PathologyOutlines.com
Image courtesy: PathologyOutlines.com

Microscopic Pathology

  • On microscopic histopathological analysis, adrenal gland can be divided into adrenal cortex and adrenal medulla.
  • Adrenal cortex can be further categorized into:
    • Zona glomerulosa (produces aldosterone)
    • Zona fasciculata (produces cortisol)
    • Zona reticularis (produces androgens)
Image courtesy: PathologyOutlines.com
Image courtesy: PathologyOutlines.com

References

  1. ↑ White PC (1994). "Disorders of aldosterone biosynthesis and action". N. Engl. J. Med. 331 (4): 250–8. doi:10.1056/NEJM199407283310408. PMID 8015573.
  2. ↑ Kater CE, Biglieri EG, Brust N, Chang B, Hirai J (1982). "Regulation of the mineralocorticoid hormones in adrenocortical disorders with adrenocorticotropin excess". Clin Exp Hypertens A. 4 (9–10): 1749–58. PMID 6291814.
  3. ↑ Aguilera G, Fujita K, Catt KJ (1981). "Mechanisms of inhibition of aldosterone secretion by adrenocorticotropin". Endocrinology. 108 (2): 522–8. doi:10.1210/endo-108-2-522. PMID 6256154.
  4. ↑ Singer DR, Shirley DG, Markandu ND, Miller MA, Buckley MG, Sugden AL, Sagnella GA, MacGregor GA (1991). "How important are suppression of aldosterone and stimulation of atrial natriuretic peptide secretion in the natriuretic response to an acute sodium load in man?". Clin. Sci. 80 (4): 293–9. PMID 1851063.
  5. ↑ Kawasaki T, Uezono K, Ueno M, Noda Y, Kumamoto K, Kawano Y, Ogata M, Fukiyama K, Omae T, Bartter FC (1980). "Influence of unilateral adrenalectomy on renin-angiotensin-aldosterone system in primary aldosteronism". Jpn Heart J. 21 (5): 681–92. PMID 7001091.
  6. ↑ Kempers MJ, Lenders JW, van Outheusden L, van der Wilt GJ, Schultze Kool LJ, Hermus AR, Deinum J (2009). "Systematic review: diagnostic procedures to differentiate unilateral from bilateral adrenal abnormality in primary aldosteronism". Ann. Intern. Med. 151 (5): 329–37. PMID 19721021.
  7. ↑ Huang WT, Chau T, Wu ST, Lin SH (2010). "Prolonged hyperkalemia following unilateral adrenalectomy for primary hyperaldosteronism". Clin. Nephrol. 73 (5): 392–7. PMID 20420801.
  8. ↑ Gadallah MF, Kayyas Y, Boules F (1998). "Reversible suppression of the renin-aldosterone axis after unilateral adrenalectomy for adrenal adenoma". Am. J. Kidney Dis. 32 (1): 160–3. PMID 9669438.
  9. ↑ Biglieri EG, Slaton PE, Silen WS, Galante M, Forsham PH (1966). "Postoperative studies of adrenal function in primary aldosteronism". J. Clin. Endocrinol. Metab. 26 (5): 553–8. doi:10.1210/jcem-26-5-553. PMID 4287160.
  10. ↑ Groth H, Vetter W, Stimpel M, Greminger P, Tenschert W, Klaiber E, Vetter H (1985). "Adrenalectomy in primary aldosteronism: a long-term follow-up study". Cardiology. 72 Suppl 1: 107–16. PMID 3902226.
  11. ↑ Yorke E, Stafford S, Holmes D, Sheth S, Melck A (2015). "Aldosterone deficiency after unilateral adrenalectomy for Conn's syndrome: a case report and literature review". Int J Surg Case Rep. 7C: 141–4. doi:10.1016/j.ijscr.2015.01.013. PMC 4336421. PMID 25604311.
  12. ↑ CHEEK DB, PERRY JW (1958). "A salt wasting syndrome in infancy". Arch. Dis. Child. 33 (169): 252–6. PMC 2012226. PMID 13545877.
  13. ↑ Wilson FH, Disse-Nicodème S, Choate KA, Ishikawa K, Nelson-Williams C, Desitter I, Gunel M, Milford DV, Lipkin GW, Achard JM, Feely MP, Dussol B, Berland Y, Unwin RJ, Mayan H, Simon DB, Farfel Z, Jeunemaitre X, Lifton RP (2001). "Human hypertension caused by mutations in WNK kinases". Science. 293 (5532): 1107–12. doi:10.1126/science.1062844. PMID 11498583.
  14. ↑ Wakabayashi M, Mori T, Isobe K, Sohara E, Susa K, Araki Y, Chiga M, Kikuchi E, Nomura N, Mori Y, Matsuo H, Murata T, Nomura S, Asano T, Kawaguchi H, Nonoyama S, Rai T, Sasaki S, Uchida S (2013). "Impaired KLHL3-mediated ubiquitination of WNK4 causes human hypertension". Cell Rep. 3 (3): 858–68. doi:10.1016/j.celrep.2013.02.024. PMID 23453970.

Template:WH Template:WS

Retrieved from "https://www.wikidoc.org/index.php?title=Hypoaldosteronism_pathophysiology&oldid=1347968"