Hyperaldosteronism / Conn Syndrome

Snapshot

• A 27-year-old male presents with headaches, muscle weakness, and high blood pressure. A basic metabolic panel showed a Na+ of 147 and K+ of 3.1. CT of the abdomen demonstrates bilateraly adrenal hyperplasia.

Introduction                                                                                                                                                                                                                                                   

• A disease caused by overproduction of aldosterone
• May be of primary or secondary causes
  • primary hyperaldosteronism
    • direct secretion of unregulated aldosteronism
    • majority are caused by unilateral adrenal (zona glomerulosal) adenoma 
      • also known as Conn’s syndrome 
    • also bilateral adrenal hyperplasia of zona glomerulosa
  • secondary hyperaldosteronism
    • increased secretion of aldosterone as a result of increased stimulation by renin
    • seen in renal artery stenosis and CHF

the kidneys see an effective “low circulating volume state” and respond by activating the renin-angiotensin-aldosterone axis.                                                                                                                                                                                                                                                                     

Presentation                                                                                                                                                                                                                                                  

• Symptoms
  • headache
  • muscle weakness
    • secondary to hypokalemia
• Physical exam
  • hypertension

hypernatremic hypertension                                                                                                                                                                                                                                                    

Evaluation                                                                                                                                                                                                                                                       

• Labs
  • hypokalemia
  • +/- hypernatremia
    • hypernatremia is rarely found due to compensatory diuresis and resulting sodium loss secondary to increased circulating volume.
  • plasma renin
    • primary hyperaldosteronism
      • low renin 
        • negative feedback inhibition by high aldosterone
    • secondary hyperaldosteronism
      • high renin
  • elevated 24-hour urine aldosterone
  • metabolic alkalosis

due to dumping of H+ for Na+                                                                                                                                                                                                                                                                     

Treatment                                                                                                                                                                                                                                                        

• Spironolactone 
  • indications
    • indicated to normalize blood pressure and hypokalemia 
  • mechanism
  • spironolactone is an aldosterone receptor antagonist