Diagnosis

Hyperaldosteronism

Etiology

Cause [kab]

• Primary (due to excessive aldosterone secretion and suppressed renin levels):

  • Idiopathic adrenocortical hyperplasia (bilateral)

  • Conn´s syndrome / aldosterone-producing adenoma with renin suppression (unilateral)

  • Adrenal carcinoma

  • Ectopic aldosterone-secreting tumors (kidneys or ovaries)

  • Familial hyperaldosteronism

• Secondary (due to elevated renin --> resulting in elevated aldosterone):

  • Renal artery stenosis

  • Renin-producing tumors

  • Renal tubular acidosis

  • Pheochromocytoma

  • Nutcracker syndrome

  • Hyperkalemia due to chronic renal failure

  • Generalized edematous states:

    • Heart failure

    • Pregnancy

    • Cor pulmonale

    • Bartter or Gitelman syndromes

    • Hepatic cirrhosis: impaired metabolism

    • Obstructive sleep apnea

    • Nephrotic syndrome

Pathophysiology [kab]

1. Aldosterone:

   • A mineralocorticoid hormone secreted by the zona glomerulosa (the outermost layer of the adrenal cortex)

   • Aldosterone production is regulated by angiotensin II, potassium, and ACTH levels

   • Promotes sodium/water retention

   • To maintain electrical neutrality in the tubular lumen:

     • Increased urinary potassium excretion --> hypokalemia

     • Increased urinary hydrogen ions excretion --> aciduria --> metabolic alkalosis

2. Hypotension --> decrease in GFR --> release of renin --> angiotensin I --> angiotensin II

   • Angiotensin II: Vasoconstrictor + Aldosterone production

   • Result: increased intravascular volume and higher blood pressure

Riskfactors for hyperaldosteronism [kab]

• Atrial fibrillation

• Family history of early-onset hypertension or cardiovascular events (age < 35)

• Family history of hyperaldosteronism

• Hypertension at age < 40 years

• Hypokalemia

• Adrenal adenoma in a hypertensive patient

• Obstructive sleep apnea

• Resistant or intractable hypertension

• Sleep apnea

Complications [kab]

• Hypertension

• Atrial fibrillation

• Left ventricular hypertrophy

• Myocardial infarction

• Stroke

• Albuminuria

• Renal failure

Epidemiology

Incidence per 100.000 [man][ike][5iq][oav][555][kab]

Prevalence per 100.000 [man][ike][5iq][oav][555][kab]

Approach

• Blood test: aldosterone > 20 ng/dL, plasma renin activity, aldosterone to renin ratio > 20:1, potassium [nms][man][kab]

• Urine sample: 24h urinary potassium > 30mmol/day

• Captopril-test

• CT abdomen

• Iodocholesterol scan

• Bilateral adrenal vein sample for aldosterone and cortisol pre- and post-ACTH

Treatment

1. Treat hypertension and hypokalemia

2. Unilateral (aldosterone producing adenoma): [kab]

   • Percutaneous and transcatheter ablation of unilateral adrenal adenoma

   • Total unilateral adrenalectomy

     • If no effect of surgery, consider:

       • Incorrect initial diagnosis

       • Underlying essential hypertension

       • Irreversible damage from chronic hyperaldosteronism

       • Other causes of hypertension: pheochromocytoma or renovascular disease

3. Bilateral:

   • Mineralocorticoid receptor blockade (spironolactone and eplerenone)

   • Potassium-sparing diuretic antihypertensive: amiloride and triamterene

   • Bilateral adrenalectomy is not recommended

   • Bilateral super-selective adrenal artery embolization

Differential diagnoses

Adrenal cortical adenoma, Adrenal cortical carcinoma, Clostridium tetani, Congenital adrenal hyperplasia, Cushings disease, Cushing syndrome, Diabetes insipidus, Essential hypertension, Hyperkalemia, Hyperphosphatemia, Hyperventilation, Hypocalcemia, Hypocapnia, Hypokalemia, Hypomagnesemia, Hypoparathyroidism, Liddle syndrome, Metabolic alkalosis, Milk-alkali syndrome, Pheochromocytoma, Preeclampsia, Renal artery stenosis