Adrenal Flashcards
Where are the adrenal glands located?
On top of kidneys
Histologically, what are the 3 layers of the adrenals?
capsule
cortex
medulla
what is the cortex made up of?
zona glomerulosa
zona fasciculata
zona reticularis
What regulates aldosterone secretion?
RAAS
Plasma K+
What is the clinical action of corticosteroids?
Suppress inflammation
suppress immune system
List disorders of the adrenal gland that are caused by primary insufficiency?
Addison’s
Congenital adrenal hyperplasia
What type are the disorders of the adrenal gland that are caused by secondary insufficiency?
pituitary/hypothalamic disorders
What is Addison’s caused by?
autoimmune destruction of adrenal cortex
Leads to reduced glucocorticoid, mineralocorticoid and sex steroids
What are the symptoms of Addison’s?
Weight loss grey-brown pigementation postural hypotension fatigue abdominal pain
How is Addison’s diagnosed?
low Na+
high K+
low cortisol
low aldosterone
How is Addison’s treated?
hydrocortisone (cortisol replacement)
fludrocortison (aldosterone replacement)
What is the mechanism of Cushing’s disease?
Excess cortisol
What are symptoms of Cushing’s?
easy bruising facial plethora striae Centripetal obesity proximal myopathy
List causes of Cushing’s
pituitary adenoma
ectopic ACTH/CRH
Adrenal adenoma
adrenal carcinoma
How is Cushing’s diagnosed?
overnight dexamethasone suppression test
24hr urinary free cortisol
late night salivary control
What are the 3 classes of hormones produced by the adrenals?
glucocorticoids
mineralocorticoids
androgens
When is CRH released and what does it stimulate?
in response to circadian rhythm and it stimulates ACTH
How does a dexamethasone suppression test work?
Administer synthetic glucocorticoid (dexomethasone). If normal - suppression of CRH and ACTH which leads to suppressed cortisol
How does an ACTH stimulation test work?
synthetic ACTH is given which should stimulate cortisol production
What is primary aldosteronism?
autonomous production of aldosterone, independent of regulators (ang II/K+)
What are features of primary aldosteronism?
hypertension
hypokalaemia
alkalosis
What are the 2 subtypes of primary aldosteronism?
Adrenal adenoma
Bilateral adrenal hyperplasia
What is adrenal hyperplasia?
Reduced cortisol secretion leads to increased ACTH to maintain adequate cortisol. Leads to hyperplasia
Presentation of adrenal hyperplasia?
sexual ambiguity
adrenal failure
What is the most common cause of Cushing’s?
Adrenal adenoma
How do you treat adrenal adenoma?
unilateral laparoscopic adrenalectomy
How do you treat adrenal hyperplasia?
MR antagonists
General treatment for adrenal insufficiency?
Cortisol and aldosterone replacement
What is produced in the zone glomerulosa?
mineralocorticoids
aldosterone
What is produced in the zone fasciulata?
cortisol
glucocorticoids
What is produced in the zone reticularis?
sex steroids
What type of cells secrete catecholamines?
neuroendocrine cells in adrenal medulla
What are the 3 causes of adrenal hyper function?
hyperplasia
adenoma
carcinoma
What is Conn’s syndrome?
primary aldosteronism - too much aldosterone
What are the 2 causes of Conn’s syndrome?
Nodular hyperplasia
adenoma
What are the 2 medullary tumours?
phaechromocytoma
neuroblastoma
Where is a phaechromocytoma derived from?
chromaffin cells of adrenal medulla
What percentage of phaechromocytomas are malignant?
10%
What can cause phaechromocytoma?
MEN2
