Secondary hypertension

Question 1

Aldosterone

• Secretion
• Regulation

Answer 1

Mineralococorticoid released from adrenal gland cortex (glomerulosa)

Regulation
- Secretion is stimulated by ACTH from anterior pituitary

Stimulators

• low Na+ (most potent)
• Increased Angiotensin II, III
• Increased K+ (low Na+)
• Acidosis

Question 2

Aldosterone function

Answer 2

Stimulates reabsorption of Na+, and thus water in kidneys

• Acts on mineralocorticoid receptors in distal/ collecting duct.
• Upregulates Na/K pump.

Stimulates secretion of K+ into urine.

Stimulates Na+ and water reabsorption from the gut, salivary and sweat glands

Stimulates secretion of H+ via the H+/ATPase in the intercalated cells of the cortical collecting tubules

Question 3

Primary hyperaldosteronism

• Definition
• Causes

Answer 3

Excess production of aldosterone from the adrenal glands, causing hypernatraemia and low renin.

Causes

• Bilateral adrenal hyperplasia (most common)
• Adrenocortical adenoma (Conn’s syndrome)

Question 4

Signs and symptoms of primary hyperaldosteronism

Answer 4

Hypernatraemia, hypokalaemia

Hypertension

Polyuria

Alkalosis

Neuromuscular

• Weakness
• Spasms
• parensthesia

Question 5

primary hyperaldosteronism investigations

Answer 5

Bloods

• HyperNa+
• HypoK+
• HypoCa
• Aldosterone: renin ratio= high (>70)

ECG (signs of HypoK)

• Flat T waves
• U waves
• Depressed T waves
• Prolonged PR, QT
• Toursards de pointes

Imaging
- Adrenal CT/ MRI for adenoma/ hyperplasia.

Question 6

Primary hyperaldosteronism treatment

Answer 6

Conn’s
- laparascopic adrenelectomy

Hyperplasia
- Spironolactone/ eplenerone or amiloride (Aldosterone antagonist)

Question 7

Secondary aldosteronism

Answer 7

High renin, leading to increased aldosterone.

Causes

• Diuretics
• CCF
• Liver failure
• Nephrotic syndrome

Sign
- normal Aldosterone:renin ratio

Question 8

Bartter’s syndrome

Answer 8

Autosomal recessive condition
- Salt reabsorption in loop of henle is blocked leading to salt wasting

Presentation

• Hypokalaemia (due to activation of RAS)
• Metabolic alkalosis

treatment

• K+ replacement
• NSAIDs
• Aldosterone inhibitors

Question 9

Phaeochromocytoma

• Definition
• Associations

Answer 9

Tumour causing excess production of adrenaline and other catecholamines.
- Tumour mainly in adrenal medulla and usually benign

Associations

• MEN
• Genetic

Question 10

Phaeochromocytoma

- Signs and symptoms

Answer 10

Episodic symptoms

• Chest tightness
• Palpitations, sweatinh
• Paraesthesia
• Hypertension
• Anxiety
• Pallor

Question 11

Phaeochromocytoma

- Treatment

Answer 11

Surgical

BP control pre-op
- Alpha-blocker (phenoxybenzamine) then beta-blockers

Question 12

Phaeochromocytoma

- Investigations

Answer 12

24 hr urine screen for

• catecholamines
• Metadrenaline/ normetadrenalines
• Creatinine

Total/ free serum metadrenaline/ normetanephrines

Plasma cathecholamines

Clonidine suppression

Imaging

• MIBG scan
• CT/MRI abdo