Cortisol Flashcards
What are alpha 1 receptors?
adrenergic receptors in blood vessels
G protein coupled receptors
allow vasoconstriction of vessels when cortisol is present
What is an adenoma?
A benign tumour formed from glandular structures in epithelial tissue.
What are the 4 causes of Cushing’s syndrome?
exogenous steroids
primary adrenal adenoma
ACTH secreting pituitary adenoma
ectopic ACTH secretion eg. small cell carcinoma of lungs
How do we do a suppression test?
Give a high dose of dexamethasone.
In ‘normal’ people it will suppress cortisol production.
Define Cushing’s syndrome
Hyperactivity of the adrenal cortex producing increased cortisol levels.
Define Cushing’s disease
Cushing’s syndrome resulting specifically from a pituitary tumour secreting ACTH.
Name 2 effects of corticosteroids
immunosuppressive
impaired healing
Define hirsutism
Excessive hairiness on women in those parts of the body where terminal hair does not normally occur.
Name the main features of Cushing’s
moon face buffalo hump hyperglycaemia menstrual disturbance osteoporosis tendency to infections hypertension central obesity purple striae muscle wasting
What things do we measure when diagnosing Cushing’s?
plasma cortisol level
plasma ACTH level
urinary excretion of degradation products of glucocorticoids
How does Cushing’s change the histology of the cortex?
cells will appear depleted in lipid
indicating that they have discharged their secretions
Define neoplasm
An abnormal growth of tissue, usually forms a mass (tumour), but not always.
What is Addison’s disease?
An insufficient level of cortical hormones in the plasma. Predominantly a decreased plasma cortisol level.
What are the main signs of Addison’s?
weight loss weakness hypotension hyperpigmentation Hyponatraemia dehydration
When and how would we perform a ACTH stimulation test?
when diagnosing Addison’s
give Synacthen (synthetic ACTH analogue) which will increase plasma cortisol levels in ‘normal’ people
if cortisol levels are not increased then it may be Addison’s
What are the actions of mineralocorticoids?
increase salt and water reabsorption
decrease potassium reabsorption
Why would excess mineralocorticoids cause hypertension?
increased sodium reabsorption
increases water retention in blood
increased pressure due to higher blood volume
What are the features of glucocorticoid deficiency?
low glucose
weight loss
nausea
hypotension
What are the features of glucocorticoid excess?
weight gain high glucose increased appetite hypertension Cushingoid
What is the ACTH precursor?
POMC
If you suspected Cushing’s, when would you measure cortisol?
at midnight when it is supposed to be its lowest
What is Addison’s usually caused by?
autoimmune destruction of adrenal cortex
What is the treatment for Addison’s?
hydrocortisone (replace glucocorticoids)
fludrocortisone (replace mineralocorticoids)
What is the most common cause of Cushing’s?
Pituitary source
When can Nelson’s syndrome occur and what is it?
after an adrenalectomy
lack of negative feedback causes uncontrolled pituitary growth
What are the roles of cortisol?
maintain blood pressure
bone formation inhibition
anti-inflammatory (inhibits histamine release)
decreases immune function
increases gluconeogenesis, lipolysis and proteolysis
