Pharmacology - Beresford Flashcards
What is Prolactomina?
And what often causes it?
When there is an overproduction of prolactin
A decrease in dopamine often causes it –> this can be fixed by using a dopamine agonist
What is Panhypopituitarism?
A deficinecy in all anterior pituitary hormones
What’s the difference between primary and secondary diseases?
Primary –> Defect with the target organ
Secondary –> Problems with the release of the hormones (eg, in the pituatary)
What are the differences between T4 and T3?
T4 is a pro-hormone of T3 –> converted by deiodinases
T3 has a shorter half life than T4
T3 has a lower binding affinity for binding proteins, but a higher affinity for receptors
Where are thyroid hormones synthesised?
Follicle cells
What is the most common form of hypothyroidism?
Atrophic (autoimmune) hypothyroidism
This uses antithyroid antibodies
More common in women –> with the incidence increasing with age
How can we differentiate between primary and secondary hypothyroidism?
TSH Levels
High = Primary
Low = Secondary
What’s the common form of hyperthyroidism?
Graves Disease
An autoimmune disease that causes the stimulation of TSH receptors
What are the 3 treatment options for hyperthyroidism?
Antithyroid Drugs –> Carbimazole/Thiamazole
Radioiodine –> If rendered euthyroid before (normal thyroid gland)
Surgery –> Only if rendered euthyroid before
Where abouts are aldosterone and cortisol specifically made in the adrenal glands?
Aldosterone –> Zona Glomerulosa (ZG)
Cortisol –> Zonas fasciculate (ZF) and Zonas reticularis (ZR)
What is aldosterone?
A mineralcorticoid
Its secretion is stimulated by elevation in angiotensin II
Binds to the MCR nuclear receptor
What are the 3 triggers for the release of renin?
Decrease in BP in the afferent arteriole
Increase in sympathetic nervous activity
Decrease in [NaCl] in the DCT
What are the 3 main effects of primary hyperaldosteronism?
Increase plasma Aldosterone:Renin Ratio (ARR)
Increased aldosterone plasma levels –> that cannot be controlled with NaCl infusion
Increased urinary K+ (and so decreased plasma levels)
What is cortisol?
A glucocorticoid
In circulation most of it is bound to plasma proteins
Binds to the GCR nuclear receptor
Secretion is stimulated by ACTH from the pituitary
What’s Addison’s Disease?
Primary adrenal insufficiency
An autoimmune disease that destroys the adrenal cortex –> so less adrenal steroid production
Characterised by an increase in CRH/ACTH production
Also due to low cortisol levels (due to destruction above) there is a negative feedback loop which creates more CRH/ACTH
What is main reason for people getting secondary adrenal insufficency?
And what does it cause?
Long term corticosteorid therapy
Suppress the hypothalamus-pituitary axis
How do you manage hypoadrenalism long term?
Replacement therapy with gluco/mineralocorticoids
Have a steroid card for emergency services
Keep an ampoule of hydrocortisone at home for injection by carers/family
What are the 2 types of hypercortisolism (cushings syndrome)?
And how do you test for them?
Primary –> Non ACTH dependent, normally caused by a cortisol-secreting adrenal tumour
Secondary –> ACTH dependent, usually caused by an ACTH-secreting pituitary adenoma (‘cushings disease’)
The high-dose dexamathasone test is the main one
How do you pharmacologically inhibit cortisol synthesis in cushings syndrome?
Metyrapone and Ketoconazole
These block the adrenal 11(B)-hydroxylase
