Endocrinology Flashcards
Aldosterone actions?
it is a?
what does it do in the DT?
CD?
mineralocorticoid steroid hormone
acts on nephrons
1) Na+ reabsorbed from DT
2) K+ secretion is increasted in DT
3) Hydrogen is secreted in CD
angiotensinogen is found in the?
converted into? by?
liver
angiotensin 1 by renin
Ang I > Ang II
angiotensin converting enzymes found in the lungs turn ang 1 > ang 2
Ang II acts on
cardiac cells
vasoconstricts
adrenal cortex > aldosterone
Hypothalamus releases ______
this acts on anterior pituitary releasing GH
GH stimulates release of ____ from ____
this acts on?
Growth hormone releasing hormone
GH stimulates liver > IGF-1
> acts on muscles, bones, myocytes
somatostatin negative feedback
ghrelin (stomach) + feedback
anterior pituitary releases 5 hormones
1) TSH
2) ACTH
3) GH
4) FSH/LH
5)prolactin
where is aldosterone produced in the adrenal cortex?
zona glomerulosa
adrenaline / catecholamines produced where in adrenal gland?
medulla
Primary hyperthyroidism?
TFT result?
thyroid is dysfunction - excessive thyroid hormone
low / suppressed TSH
high t3/t4
causes of hyperthyroidism?
Graves
Inflammation - thyroidistis
solitary toxic nodule
toxic multinodular goitre
what are the antibodies in Graves disease?
TSH receptor stimulating antibodies
anti thyroid perioxidase Abs
what imaging in thyroid disease?
radioisotope USS of thyroid gland
how is a radioisotope scan carried out?
iodine given orally or IV
gamma camera detects gamma rays from the iodine
function info given
radioisotope findings
Grave?
Toxic multinodular / adenoma
Thyroid cancer?
diffuse high uptake
focal uptake
abnormally low uptake
Causes of hypothyroidism?
hashimotos thyroiditis
iodine deficiency
what is complications of hyperthyroidism?
thyroid storm / thyrotoxicosis
AF >
exophthalmos
opthalmoplegia
pretibial myxoedema
Thyroid storm management
admission to hospital
antithyroid medication
steroids
+ supportive care
Medical management of Graves?
carbimazole - 40mg
propranalol - symptom control
what 2 antibodies found in hashimotos?
anti thyroglobulin
anti thyroid perioxidase
Mx of hypothyroidism?
how long till check?
Levothyroxine 50-100mcg od
8-12 weeks
what would be considered a normalisation of thyroid?
TSH value 0.5-2.5 mU/l
Pregnancy and hypothyroidism
levothyroxine changes?
dose increase by 25-50micrograms
which supplements commonly given affect levothyroxine absorption?
iron
calcium
give 4 hours apart
what 2 drugs can impact thyroid?
lithium
amiodarone
levothyroxine is?
synthetic t4 > t3
what are the 2 types of corticosteroid hormones?
glucocorticoids
mineralocorticoids
Cushing disease refers to?
pituitary adenoma > ACTH
> cortisol
causes of cushing syndrome
Cushing D
adrenal adenoma
paraneoplastic
exogenous steroids
Cushing syndrome diagnosis?
dexamethasone suppression test
A normal response to dexamethasone
abnormal
cortisol is suppressed
lack of cortisol suppression indicates CS
Ix cushing
FBC - wcc
u&es - hypokalaemia
MRI brain
CT chest - SCLC
CT abdo - adrenal tumour
Mx of cushing?
pituitary adenoma?
adrenal?
trans sphenoidal
surgical
low dose dexamethasone
dosage?
1mg given at night
cortisol checked in the am
failure of suppression of cortisol indicates?
CS
high dose dexamethasone test?
differentiates between?
2mg
pituitary / adrenal cause
high enough to suppress pituitary adenoma bur nor adrenal
excess growth hormone features?
superior bitemporal hemianopia
frontal bossing
sweaty
large nose
macroglossia
prganthism
acromegaly Ix?
confirmatory test?
what dose?
what is normal?
Insulin Like Growth factor -1
> venous blood sample
> immunoassay
growth hormone suppresion test
75g of glucose drink
> 2 hours later test GH
suppressed is normal
Imaging for acromegaly
MRI brain to visualise pituitary adenoma
definative mx of acromegaly?
transphenoidal surgery
example of a somatostatin analogue?
octreotide
which 2 can be used in medical management of acromegaly?
octreotide
bromocriptine
blocks GH release
what is negative feedback to pituitary gland producing GH?
somatostatin
Prolactinoma
1st line management?
dopamine agonist
cabergoline
bromocriptine
causes of raised prolactin
prolactinoma
pregnancy
oestrogen
stress
PCOS
acromegaly
drugs causing prolactinoma?
metoclopramide
haloperidol
SSRI / opioid
Initial tests for phaeochromocytoma
plasma free metanephrines
24hr urine catecholamines
Mx of phaeo
alpha blockade
> beta blockade
>surgical removal of the tumour
Adrenal insufficiency how to diagnose?
short synacthen test
cortisol checked
should double
