5. Adrenal causes of hypertension Flashcards
Describe the anatomy of the adrenal glands
- Two triangular shaped organs about 1.5 inches in height and 3 inches in length
- located on top of each kidney
- each adrenal gland is comprised of two distinct structures - outer part of the adrenal glands is called the adrenal cortex. The inner region is known as the adrenal medulla
Describe the three layers of the adrenal cortex
GFR
Glomerulosa - aldosterone
Fasciculata - sugar regulation (cortisol)
Reticularis - androgens
Salt, sugar, sex, the deeper it goes, the sweeter it gets
Adrenal causes of hypertension
primary hyperaldosteronism - adenoma of the Zona glomerulosa if unilateral, hyperplasia if bilateral
rare genetic causes
phaeochromocytoma (phaeo) - tumour of the adrenal medulla
some forms of congenital adrenal hyperplasia
enzyme defect- uncommon - results in build up of precursors of aldosterone
RAAS pathway
liver releases angiotensinogen, renin from kidney converts it to angiotensin I, ACE converts that to angiotensin II, which stimulates aldosterone secretion.
Angiotensin II is a potent vasoconstrictor, raising BP
Aldosterone causes reabsorption of water and sodium into blood at kidney, raising BP
hypertension due to primary hyperaldosteronism: who to screen? and difference between that and normal hypertension?
Screen people with:
- hypokalaemia
- resistant hypertension (3 drugs)
- younger people
individuals with PA have more vascular and renal pathology than people with essential hypertension and similar blood pressure
What tests are used for primary hyperaldosteronism?
Initial screening tests:
Supressed renin
Normal/high aldosterone
Confirmatory tests:
Oral or IV Na+ suppression test - suppressing Na+ should suppress aldosterone
Tests for specific aetiology i.e. secreting adenoma or bilateral hyperplasia:
adrenal CT scan
adrenal venous sampling - is the aldo secretion unilateral?
Metomidate PET CT
What is the treatment for primary hyperaldosteronism?
Unilateral adenoma:
- laparoscopic adrenalectomy
- medical treatment (sometimes)
bilateral hyperplasia:
-medical treatment (aldosterone antagonists) e.g. spironolactone or eplerinone
phaeochromocytoma
Tumour of the adrenal medulla - modified post-ganglionic nerve cells innervated by preganglionic nerves
Products of the adrenal medulla
catecholamines:
- dopamine
- noradrenaline
- adrenaline
tyrosine made into L-DOPA made into dopamine made into noradrenaline which with cortisol makes adrenaline
Adrenal medulla role
Not essential for life
Stress/fight/flight
Biological effects of noradrenaline (alpha 1 and 2)
vasoconstriction - increased BP and pallor
Glycogenolysis
Biological effects of adrenaline (Alpha 1, beta 1 and 2)
vasoconstriction
vasodilation in muscle
increased heart rate
sweating
Presentation of phaechromocytoma
20% of phaeos diagnosed in mortuary
Presentation:
Spells -headache, sweating, pallor, palpitation, anxiety
Hypertension - permanent, intermittent
Family history
Severe autosomal dominant genetic conditions are associated with phaeochromocytoma
neurofibromatosis type 1 (NF1)
Multiple endocrine neoplasia type 2 (MEN2)
Von Hippel-Lindau syndrome
NF1
Can cause phaeochromocytoma
Tumours under skin or deeper which can show up at any age but especially adolescence
These tumours grow on nerves - neurofibromas
Have axillary freckling
