Conn's Syndrome

Key Facts

Symptoms

Diagnosis

Treatment

Primary hyperaldosteronism - excess production of aldosterone, independent of the renin-angiotensin system

  • Results in increased sodium and thus water retention (resulting in increased BP) and decreased renin release
  • K loss
  • Combination of hypokalaemia and hypertension

Conn’s syndrome is due to a adrenal adenoma that secretes aldosterone

Often asymptomatic

Hypertension

  • Due to an increase in blood volume
  • Can be severe and is associated with renal, cardiac and retinal change
  • May not always be present

Hypokalaemia

  • Weakness/cramps
  • Paraesthesia
  • Polyuria
  • Polydipsia

Hypokalaemic ECG

  • Flat T waves
  • ST depression
  • Long QT

Serum hypokalaemia

  • Not always present

Plasma aldosterone: renin ratio (ARR)

  • Initial screening test
  • Spirolactone and epiereone should be stopped 6 weeks before test
  • Aldosterone is much higher - NOT DIAGNOSTIC, used mainly for screening

CT or MRI adrenals to differentiate adenomas from hyperplasia

Laparoscopic adrenalectomy

Aldosterone antagonist e.g. ORAL SPIRONOLACTONE for 4 weeks pre-op to control BP and K

Epidemiology

Rare condition accounting for <1% of all hypertension

Aetiology

2/3rds - adrenal adenoma that secretes aldosterone - Conn's syndrome

1/3rd - bilateral adrenocortical hyperplasia

Risk Factors

Pathophysiology

Hypertension in patients

With hypokalaemia before diuretic therapy

Resistant to conventional antihypertensive therapy e.g. more than 3 drugs

With accelerated (malignant) hypertension

With unusual symptoms e.g. sweating attacks or weakness

Under 35yrs with no family history of hypertension

Disorder of the adrenal cortex characterised by excess aldosterone production leading to Na and water retention and K loss, and the combination of hypokalaemia and hypertension due to aldosterone producing carcinoma

Differential Diagnosis

Must be differentiated from secondary hyperaldosteronsim which arises when there is EXCESS RENIN which stimulates aldosterone release

Caused by reduced renal perfusion which can be due to:

Diuretics

Congestive cardiac failure

Accelerated hypertension

Hepatic failure

Renal artery stenosis

Increased plasma aldosterone levels that are not suppressed with 0.9% saline infusion - DIAGNOSTIC