Primary hyperaldosteronism

Question 1

Primary hyperaldosteronism: Excess production of aldosterone, independent of the RAAS 🡪 causing _________ retention, & ↑ ___ excretion, & ↓ ________ release

Includes 2 conditions:

1) _____________ – i.e. U/L Adenoma of 1 adrenal
2) ____________ – i.e. B/L idiopathic, age related adrenal hyperplasia

Answer 1

Na & water;

K;

Renin

Conn’s Syndrome;

Bilateral Adrenal
Hyperplasia

Question 2

What is Conn’s syndrome caused by?

Answer 2

Hyperaldosteronism caused by a solitary (usually U/L) aldosterone-producing adenoma

Question 3

What are the causes of primary hyperaldosteronism?

Answer 3

• Bilateral adrenocortical hyperplasia (idiopathic, usually a/w old age)
• Conn’s syndrome
• Adrenal carcinoma (rare)
• Glucocorticoid remediable aldosteronism (rare)
• CAH

Question 4

What are the causes of secondary hyperaldosteronism?

Answer 4

• Renal artery stenosis
• Renal hypoperfusion from shock
• CCF, hepatic failure
• Pheochromocytoma (causing RAS)
• diuretics
• renin secreting tumour

Question 5

What are the clinical features of primary hyperaldosteronism?

Answer 5

Asymptomatic

Signs of hypokalaemia

• Proximal weakness
• Cramps
• Paraesthesia
• Possible Hypokalaemic
• Periodic Paralysis

Polyuria, Polydipsia: Sustained Hypokalaemia 🡪 desensitization of tubules to ADH 🡪 Nephrogenic DI

Hypertension:
- Think of Primary hyperaldosteronism if
Hypertension associated with hypokalaemia
- Suspect in Refractory hypertension (e.g. Despite >3 anti-hypertensives, w/ 1 being a diuretic)
- Hypertension occurring before 40 years of age (especially in women)

Metabolic Alkalosis (NAGMA)

Mild Hypernatraemia

Absence of significant edema

Question 6

What are the investigations for primar hyperaldosteronism?

Answer 6

Screening

• Serum ↓ Renin: aldosterone ratio
• Serum K levels
• Renal panel (urine K:Cr ratio)

Diagnosis of Primary Hyperaldosteronism

1) Saline Suppression Test: NaCl within N/S will suppress Renin and hence Aldosterone due to increased distal NaCl delivery
- Infusion of N/S 2L over 2hrs
- Aldosterone >10 = confirmed primary hyperaldosteronism
2) Fludrocortisone Suppression Test
3) Captopril challenge Test – Aldosterone should ↓ due to ACE-I resulting in ↓ Aldosterone production

After establishing diagnosis, locate source of abnormality

1) CT or MRI of adrenals: There is high chance of picking up a incidentaloma of the adrenal, and wrongly diagnose a patient w/ hyperaldosteronism!. Hence, we don’t use CT Adrenals to Dx!
2) Adrenal venous sampling
- >3-fold difference from one side to the other: adenoma is likely
- Best, but most invasive method

Genetic testing for glucocorticoid remediable aldosteronism

Question 7

What is the management of primary hyperaldosteronism?

Answer 7

Adenoma: Surgical Resection
- May require 4 weeks spironolactone pre-op to control BP and K+

Bilateral: Medical therapy w/ aldosterone antagonists

• Spironolactone (dirty drug, SE: Gynaecomastia, Erectile Dysfunction)
• Eplerenone