Endocrinology Flashcards
FLAT PIG for anterior pituitary hormones
FSH
LH
ACTH
TSH
PRL
Intermediate - MSH
GH
too much hormone
try to suppress it
too little hormone
try to stimulate it
what imaging modalities would you use for adrenals and pituitary
CT - adrenal
MRI - pituitary
approaches to endocrine
phenotype
biochemistry: suppression/stimulation tests, levels
imaging
phenotype of hyperthyroidism
heat intolerance weight loss anxiety tremor tachycardia palpitations diarrhoea oligo/amenorrhoea exophthalmos dry skin and fine brittle hair pretibial myxoedema insomnia AF
biochemistry of primary hyperthyroidism
low TSH
high free T3/4
primary hyperthyroidism
problem with the thyroid itself resulting in negative feedback
secondary hyperthyroidism
pituitary abnormality resulting in thyroid abnormality
causes of primary hyperthyroidism
Graves disease TMG Adenoma Thyroiditis drugs - amiodarone
what is Graves disease
autoimmune condition
anti-TRAb - thyroid receptor antibodies
continuously stimulates iodine uptake into thyroid and production of T3/4
smooth goitre with bruit
features pathognomonic of Graves
pretibial myxoedema
Graves ophthalmopathy - asymmetrical swelling and exophthalmos
thyroid acropachy
management of sight threatening swelling of the eye
steroids
investigations for hyperthyroidism
thyroid levels
USS
nuclear medicine uptake scan
which ATD is used in the first trimester of pregnancy
PTU
ATD examples
carbimazole
PTU
management of hyperthryoidism
propranolol for symptoms (non-selective B blocker)
carbimazole, PTU
radioactive iodine
thyroidectomy
side effects of carbimazole and PTU
carbimazole - agranulocytosis
PTU - liver failure
risks of thyroidectomy
RLN damage
damage to parathyroids
thyroid storm
extreme hyperthyroidism
features of thyroid storm
high temp dehydration excess sweating sinus arrhythmia diarrhoea pre renal failure weight loss myopathy CK rise delirious coma psychosis
management of thyroid storm
1. propranolol PTU/carbimazole hydrocortisone 2. iodine lithium look for underlying causes
phenotype hypothyroidism
weight gain cold intolerance low mood low energy bradycardia constipation menorrhagia
biochemistry of primary hypothyroidism
high TSH
low free T3/4
causes of primary hypothyroidism
autoimmune Hashimoto's thyroiditis post-hyperthyroidism treatment iodine deficiency amiodarone lithium interferon irradiation sarcoidosis amyloidosis surgery
management of hypothyroidism
levothyroxine
worry abut levothyroxine in elderly
suddenly increase their heart function which can exacerbate heart conditions eg HTN, HF
what is myxoedema coma
extreme hypothyroidism
features of myxoedema coma
depressed thinning hair oedema bradycardia constipation carpal tunnel cool peripheries hypothermia loss of outer 1/3rd eyebrow hair
management of myxoedema coma
levothyroxine
steroids
hypothyroidism causes high/low MCV
high
symptoms of hypercalcaemia
bones - bone pain moans - psychiatric stones - renal groans - abdo pain thrones - constipation dehydration and thirst confusion polyuria myopathy depression short QT segment - ECG
treatment of acute hypercalcaemia
0.9% NaCl
IV bisphosphonates
identify cause and reverse it
symptoms of hypocalcaemia
paraesthesia Trousseau sign - carpopedal spasm Chovsteks sign - twitching on tapping face tetany long QT segment - ECG fatigue and muscle weakness fits, seizures
treatment of acute hypocalcaemia
IV calcium gluconate 10ml, 10% over 10 min
management of acute hyperkalaemia
ECG stop any infusion containing K IV calcium gluconate to stabilise cardiac membrane IV insulin to drive K intracellularly salbutamol does the same haemodialysis is a last line
phenotype of reduced anterior pituitary function
large tumour bulk - adenoma - cause reduction in hormone production and therefore function
causes of hypopituitarism
tumours - adenoma, craniopharyngeoma
vascular - Sheehans syndrome, severe hypotension
infection - meningitis, TB, syphilis, HIV/AIDS
hypothalamic disorders - tumours, functional, GHRH deficiency
iatrogenic - radiation, hypophysectomy
miscellaneous - sarcoidosis, haemochromatosis
features of hypopituitarism
secondary amenorrhoea in premenopausal women
bitemporal hemianopia
general order of loss of pituitary function
GGAT Gonadotrophins GH ACTH TSH
low LH and FSH is a post menopausal woman is a red flag?
yes
normally a post menopausal woman should have high LH and FSH and so if it low it might be due to a pituitary pathology
stimulation test for GH
insulin tolerance test
insulin to bring down blood glucose to stimulate GH
in anterior pituitary hormone excess, it generally occurs to all hormones produced, true or false
false
usually one hormone goes beserk
most common cause of hormone excess in anterior pituitary
adenoma
FSH/LHomas tend to be detected quite late, true or false
true
usually removed surgically
can cause hypopituitarism
features of ACTH excess
Cushingoid appearance weight gain, puffy face, central obesity, striae thin skin, bruising, hirsutism, muscle wasting, osteoporosis, frontal balding, acne, buffalo hump poor healing thin limbs ^HTN ^blood glucose fluid retention depression, psychotic, poor sleep immunosuppression
causes of Cushing’s
exogenous steroid use
Pituitary - Cushing’s disease
adrenal adenoma / hyperplasia
ectopic - SCLC
investigation for excess cortisol
DXM suppression test
very potent steroid to feedback to pituitary to switch off ACTH and down regulate cortisol
adrenal anatomical regions
cortex outside (secretory) medulla inside (neuroendocrine)
layers of the cortex
GFR zona: glomerulosa fasiculata reticularis
what does zona glomerulosa secrete
aldosterone - minerlocorticoid
what does the zona fasiculata secrete
cortisol - corticosteroid
what does the zona reticularis secrete
adrenal androgens
- fairly clinical insignificant
what does the adrenal medulla secrete
adrenaline
noradrenaline
- catecholamines
what are steroid ultimately derived from
cholesterol –> pregnenolone –> steroid
only glucocorticoids negatively feedback on ACTH, true or false
true
what do the mineralocorticoids negatively feedback on
RAAS
What is a cause of hypoadrenalism
Autoimmune Addisons disease Malignancy Freiderichson-Waterhouse syndrome - haemorrhage/hypotension Infections - TB, HIV Excess steroid therapy Haemochromatosis
clinical features of hypoadrenalism
hypotension dizzy weight loss tanned / hyperpigmentation of creases hypoglycaemia diarrhoea
why do people with hypoadrenalism have tanned skin
^ ACTH production results in ^MSH causing bronzed skin
why would you do a BM in someone with hypoadrenalism
low cortisol causes low glucose
biochemical features of hypoadrenalism
hyponatraemia
hyperkalaemia
hypoglycaemia
low early morning cortisol
dynamic testing for hypoadrenallism
synacthen test
give dose of ACTH to see whether there is a spike in cortisol levels
take bloods at 0, 30 and 60 min
(also measure ACTH at 0 min)
further imaging for hypoadrenalism
CT adrenal
management of hypoadrenalism
hydrocortisone (cortisol replacement)
fludrocortisone (aldosterone replacement)
if patients are acutely unwell and have hypoadrenalism, what is important to have
steroid card and emergency hydrocortisone
what adrenal gland hormones can you have too much of
aldosterone
cortisol
catecholamines
function of aldosterone
mineralocorticoid
activates Na/K ATP channel and resorb Na at the kidney
water follows Na resulting in increased circulating blood volume and maintains BP
what is the RAAS
Angiotensinogen is produced in the liver
Renin from the kidneys break this down into Ag I
ACE then breaks this into Ag II
Ag II then acts on the kidneys to resorb Na and causes
What is Conns syndrome
excess aldosterone
clinical features of aldosterone excess
treatment resistant HTN
biochemistry of aldosterone excess
hypokalaemia
technically hypernatraemia but because water follows Na, Na levels remain normal
dynamic testing for aldosterone excess
renin:aldosterone ratio
renin low
aldosterone high
what suppression test do you do for aldosterone excess
2L saline suppression test
examples of aldosterone antagonist drugs
spironolactone
eplerenone
why do people with Conns disease cause hyperchloraemic metabolic alkalosis
hyperchloraemia
aldoseterone causes retention of HCO3 and loss of H
people with addisons disease get metabolic acidosis/alkalosis
acidosis
treatment of Conns disease
surgical removal of Conns tumour
or spironolactone treatment
what adrenal disease causes cortisol excess
Cushing’s syndrome
phenotype of Cushings syndrome
buffalo hump central obesity limb muscle weakening - proximal myopathy frontal balding striae moon face hypertension IGT thin skin, easy bruising
dynamic testing for cushings
DXM suppression test
response to DXM suppression test in: adrenal pituitary ectopic as a cause of Cushings
adrenal - suppressed in low dose DXM
pituitary - suppressed in high dose DXM
ectopic - very high, no suppression
drug for cushings syndrome
metyrapone
only used for elderly people
what disease is caused by excess catecholamines
phaeochromocytoma
tumour of chromaffin cells
clinical features of phaeochromocytoma
headaches hyperglycaemia sweating palpitations pallor hypertension postural symptoms episodic symptoms
investigation for excess catecholamines
24 hour urine metanephrine collections
(2 collections)
plasma also (2nd line test)
medical management of phaeochromocytoma and why
alpha (phenoxybenzamine/doxazosin) then beta blockers
alpha receptors are in blood vessels
beta receptors are in the heart
this should be done before surgery to prevent squeezing out pre formed hormones causing a crash response
why alpha then beta blockade in phaeochromocytoma
blocking beta first would mean that adrenaline would saturate the alpha receptors and cause extreme vasoconstriction and hypertension
functional imaging for phaeochromocytoma
MIBG scan
10% rule for phaeochromocytoma
bilateral malignant genetic kids extra adrenal
which vitamin is essential for Ca metabolism
Vit D3
which mineral is important for calcium regulation
Mg
without it, PTH cannot be released or work properly
how many parathyroid glands in the body
4
where does PTH act
bone - osteoclasts activates
kidneys - increased Ca resorption and decreased PO4
gut - increased Ca + PO4 reabsorption
classifications of parathyroidism
primary
secondary
tertiary
primary hyperparathyroidism
idiopathic inappropriate secretion of PTH
^PTH + Ca
low PO4
secondary hyperparathyroidism
appropriate hypersecretion of PTH secondary to low Ca
^PTH
low Ca and PO4
tertiary hyperparathyroidism
autonomous hypersecretion of PTH / 2ndary HPT gone beserk
most commonly seen in CKD
phenotype of hypercalcaemia
bones - osteoporosis stones - renal groans - abdominal moans - psychiatric thirsty polydipsia polyuria
imaging for parathyroids
sestamibi scan
causes of hypercalcaemia
Endocrine - HPT, MEN, FHH Malignancy - mets, PTHrp, myeloma Granulomatous disease - sarcoid, TB miscellaneous - AKI, milk alkali syndrome Medications - lithium, thiazides, vit D
first investigation in someone with hypercalcaemia
PTH levels
management of hypercalcaemia acutely
IV fluids
bisphosphonates
addisons can cause hypercalcaemia?
yes
