Secondary hypertension Flashcards
Aldosterone
- Secretion
- Regulation
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
Aldosterone function
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
Primary hyperaldosteronism
- Definition
- Causes
Excess production of aldosterone from the adrenal glands, causing hypernatraemia and low renin.
Causes
- Bilateral adrenal hyperplasia (most common)
- Adrenocortical adenoma (Conn’s syndrome)
Signs and symptoms of primary hyperaldosteronism
Hypernatraemia, hypokalaemia
Hypertension
Polyuria
Alkalosis
Neuromuscular
- Weakness
- Spasms
- parensthesia
primary hyperaldosteronism investigations
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.
Primary hyperaldosteronism treatment
Conn’s
- laparascopic adrenelectomy
Hyperplasia
- Spironolactone/ eplenerone or amiloride (Aldosterone antagonist)
Secondary aldosteronism
High renin, leading to increased aldosterone.
Causes
- Diuretics
- CCF
- Liver failure
- Nephrotic syndrome
Sign
- normal Aldosterone:renin ratio
Bartter’s syndrome
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
Phaeochromocytoma
- Definition
- Associations
Tumour causing excess production of adrenaline and other catecholamines.
- Tumour mainly in adrenal medulla and usually benign
Associations
- MEN
- Genetic
Phaeochromocytoma
- Signs and symptoms
Episodic symptoms
- Chest tightness
- Palpitations, sweatinh
- Paraesthesia
- Hypertension
- Anxiety
- Pallor
Phaeochromocytoma
- Treatment
Surgical
BP control pre-op
- Alpha-blocker (phenoxybenzamine) then beta-blockers
Phaeochromocytoma
- Investigations
24 hr urine screen for
- catecholamines
- Metadrenaline/ normetadrenalines
- Creatinine
Total/ free serum metadrenaline/ normetanephrines
Plasma cathecholamines
Clonidine suppression
Imaging
- MIBG scan
- CT/MRI abdo