Endocrinology 1 Flashcards
nervous vs endocrine system?
nervous = fast on and fast off endocrine = slow on and slow off
main endocrine organs?
pituitary thyroid pancreas adrenals gonads parathyroids
what does anterior pituitary produce?
FLAT PIG FSH LH ACTH TSH prolactin intermediate - MSH Growth hormone
what does posterior pituitary make?
oxytocin
ADH
what does pancreas make?
insulin (beta cells)
glucagon (alpha cells)
what do adrenals make?
mineralocorticoids - aldosterone
glucocorticoids - cortisol
adrenal androgens - DHEA
adrenaline and noradrenaline
where are most androgens made?
gonads
steps in establishing endocrine disorder?
look for phenotype first
then check biochemistry
if biochemical abnormality confirmed then do imaging to check for anatomical problem (eg adenoma in pituitary)
then look at treatment
basics of testing hormone levels?
if worried about too much hormone then try and suppress it
if worries about too little hormone then try to stimulate it
things to be aware of when testing hormone levels?
some hormones arent secreted at constant level (eg some have diurinal variation or growth hormone which is released in bursts)
general rule for endocrine imaging?
CT best for abdominal (eg adrenals)
MRI best for pituitary
main functions of thyroid?
produces T3, T4 and calcitonin
regulates metabolism
job of parathyroid?
calcium regulation
job of adrenals?
fight or flight
emergency control centre
layers of adrenals?
outer cortex - aldosterone, cortisol and androgens
inner medulla - adrenaline and noradrenaline
zones of adrenals?
zona glomerulosa
zona faciculata
zona reticularis
what is MSH?
melanocyte stimulating hormone
most common endocrinopathy?
diabetes then thyroid
are thyroid hormones stable?
yes
features of hyperthyroidism?
tachycardia weight loss sweating/heat intolerance loose stools exophthalmos irregular periods or amenorrhoea fine tremor anxiety trouble sleeping
thyroid biochemistry?
production is 80% T4 and 20% T3
T3 is the active hormone (T4 becomes deiodinated)
primary hyperthyroid biochemistry?
low TSH and high T4
secondary hyperthyroid biochemistry? (problem in pituitary or rarely in hypothalamus)
high TSH and high T4
causes of primary hyperthyroid?
graves disease (autoimmune)
toxic multinodular goitre
solitary toxic adenoma (hot nodule)
can sometimes get a thyroiditis where inflammation can initially cause increased release of hormones before becoming hypothyroid
causes of secondary hyperthyroid?
TSH secreting pituitary tumour
exogenous T3 or T4 (factitious or iatrogenic hyperthyroidism)
ectopic thyroid tissue
what is graves disease?
autoimmune hyperthyroidism (most common cause of hyperthyroid) thyroid receptor antibodies (Trab) attach onto TSH receptors, stimulating uptake of iodine into thyroid and production of T4 and T3
other symptoms of graves?
eye disease (exopthalmos) thyroid acropachy (clubbing) pre-tybial myxoedema
management of exopthalmos in graves disease?
can be an emergency if pressure increases
steroids given
diagnosis of hyperthyroid?
thyroid function tests
can measure Trab antibodies (+ve = graves, -ve = do US to look for other cause)
thyroid uptake scans then done to check if single/multi and functionality (diffuse uptake = graves)
features of graves disease on investigation?
low TSH high T4 \+ve Trab antibodies smooth goitre uniform uptake scan uniform gland on US and palpation can have bruits (indicates increased blood supply)
what is multinodular goitre?
lots of areas of normal looking thyroid tissue which has gotten out of control and no longer listening to pituitary
what can cause thyroiditis?
autoimmune
post-partum
amiodarone
pattern of thyroiditis?
inflammation causes all thyroid hormone reserves to be chucked out of the thyroid
so initially hyperthyroid then hypothyroid
medical management of hyperthyroidism?
carbimazole (mainstay)
propothiouracil (PTU)
beta blockers can be used to help symptoms while waiting on carbimazole/PTU to work (non-selective ones such as propanalol)
radioactive iodine (taken up into thyroid and radiation obliterates the thyroid)
side effects of carbimazole?
agranulocytosis (loss of neutrophils)
jaundice (more common in PTU)