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hyperaldosteronism

hyperaldosteronism

Introduction

  • hyperaldosteronism is due to excessive aldosterone secretion from the adrenals and causes hypertension with hypokalaemia and metabolic alkalosis
  • it is characterized by a high serum level of aldosterone and a low serum renin level if primary and a high serum renin level is secondary
  • the same clinical features but with normal or low levels of aldosterone may be caused by pseudoaldosteronism which may be due to:
    • licorice ingestion
      • licorice inhibits the 11-beta hydroxysteroid dehydrogenase type II (Protein:HSD11B2) enzyme resulting in inappropriate stimulation of the mineralocorticoid receptor by cortisol
    • high gluocorticosteroid levels
    • Liddle's syndrome (an extremely rare genetic disorder)

Aetiology

primary hyperaldosteronism

  • note: serum renin levels will be low
  • idiopathic bilateral adrenal cortical hyperplasia (70% of cases)
  • adrenal adenoma (Conn's syndrome)
  • adrenal carcinoma is an extremely rare cause
  • glucocorticoid remediable aldosteronism (aldosterone synthase hyperactivity), is an autosomal dominant disorder in which the increase in aldosterone secretion produced by ACTH is no longer transient.

secondary hyperaldosteronism

  • this is due to overactivity of the renin–angiotensin–aldosterone system (RAAS) resulting from high renin levels
    • massive ascites
    • cor pulmonale
    • a renin-producing tumor leads to increased aldosterone eg. juxtaglomerular cell tumor
    • renal artery stenosis causes reduced blood supply across the juxtaglomerular apparatus which stimulates the production of renin
    • hyporeabsorption of sodium (as seen in Bartter and Gitelman syndromes)

Diagnosis

  • elevated serum aldosterone
  • serum aldosterone:renin ratio to determine primary vs secondary
  • serum cortisol to exclude cortisol causes
hyperaldosteronism.txt · Last modified: 2019/08/17 17:08 (external edit)