Endocrinology Flashcards
for which 2 groups of ppl is BMI inaccurate
pregnant
ppl with large amount of muscle mass
how to calculate BMI
kg / m^2
underweight BMI
<18.5
normal BMI
18.5 - 24.9
overweight BMI
25 - 29.9
obese BMI class 1 2 3
class 1
30 - 34.9
class 2
35 - 39.9
class 3
40+
management for class 1 obese
1st line = lifestyle modifications
consider orlistat
Mech of action of osrlistat
pancreatic lipase inhibitor
management of class 2 obesity with comormidities / class 3 obesity / other Tx been ineffective
bariatric surgery
which classes of obesity qualify for bariatric surgery
management of class 2 obesity with comormidities / class 3 obesity / other Tx been ineffective
2 roles of cobalamin / vit b12
rbc synthesis
myelination
where is b12 absorbed
terminal ileum
which foods is b12 found in
animal products
4 causes of b12 deficiency
pernicious anaemia
gastrectomy
vegan diet
disease of terminal ileum: crohns or ileocaecal resection
which cancer does pernicious anaemia increase risk of
gastric
what are the 2 types of antibodies that can be found in pernicious anaemia
anti - IF antibodies
anti gastric parietal cell antibodies
clinical features of vit b12 deficiency
anaemia (fatigue, pallor, SOB etc)
peripheral neuropathy (tingling, numbness etc)
dementia
glossitis
b 12 deficiency management
IM supplementation of vitamin B12 (hydroxocobalamin)
should you replace b12 or folate first
b12
describe the rbc’s in b12/folate deficiency
Macrocytic, Megaloblastic Anaemia
→ decreased Hb,
increased MCV,
hyperchromic RBCs,
hypersegmented neutrophils
describe homocysteine levels in b12 and folate deficiency
elevated in B12 & Folate deficiency
describe Methylmalonic acid (MMA) levels in B12 and folate deficiency
elevated in B12 deficiency,
normal in folate deficiency
2 roles of folate
DNA synthesis and amino acid metabolism
which vitamin is folate
vit B9
which food is folate found in
green leafy veg
4 causes of folate deficiency
malabsorption (small bowel disease due to IBD or coeliac disease),
malnutrition (chronic alcohol use),
increased requirement (pregnancy),
drug related (methotrexate, antiepileptics)
clinical features of folate deficiency
anaemia
glossitis
fetal spinal bifida if mother is deficinet
what does the foetus get if the mother is folate deficient
fetal spinal bifida
anacephaly
main difference in clinical features between vit b12 and folate deficiency
folate deficiency does not result in neurological symptoms
Tx for folate deficiency
oral folate supplementation
how much folate should pregnant women take to prevent fetal neural tube defects
400mcg of folic acid until the 12th week of pregnancy
definition of hypothermia
< 35
definition of hyperthermia
> 40
what is mild hypothermia
35 - 32
features of mild hypothermia
tachycardia, tachypnoea, shivering, vasoconstriction
what is moderate hypothermia
28 - 32
features of moderate hypothermia
arrhythmias, hypotension, resp depression, cognitive impairment, may cease to shiver
what is severe hypothermia
< 28
features of severe hypothermia
loss of/reduced consciousness
coma
arrhythmia
apnoea
fixed dilated pupils
which temp do you measure for hypothermia
core body temp
ECG hypothermia features
J / Osborn waves
broad QRS complex
mild hypothermia management
passive external rewarming (remove wet clothing, cover with blankets, warm room)
moderate hypothermia management
active external rewarming (warm blankets, radiant head, forced warm air)
severe hypothermia management
IV warmed crystalloid
hypothermia complications
arrhythmias
hypoglycaemia
hyperkalaemia
GI disorders
rhabdomyolysis
which temp do you measure for hyperthermia
rectal temp
heat stroke vs heat exhaustion
heat stroke = hyperthermia with CNS dysfunction
heat exhaustion = hyperthermia without CNS dysfunction
what are the 2 types of heat stroke
classic (due to external environment)
exertional
heat stroke symptoms
confusion
seizures
loss of consciousness
delirium
heat stroke management
stabilisation (ABC, remove clothes)
rapid active cooling (full body immersion in ice water)
heat exhaustion symptoms
nausea
dizziness
weakness
muscle cramps
fatigue
headache
heat exhaustion management
oral isotonic fluids
active cooling
which LDL and HDL levels promote atherosclerosis
Elevated LDL and reduced HDL
familial hypercholestrolaemia inheritance pattern and mutation
Autosomal dominant inherited disorder
Caused by a mutation in the gene coding the LDL receptor
clinical features of hyperlipidaemia
Xanthomata → nodular lipid deposits in the skin and tendons
Xanthelasma → yellow, flat plaques on upper eyelids
(xanthelasma is a type of xanthomata)
Corneal Arcus → crescentic-shaped opacity at the periphery of the corne
Ix for hyperlipidaamia
Lipid Profile → total cholesterol, HDL, LDL and trigylcerides
Tests for Secondary Causes → HbA1c/Fasting glucose, TSH, LFTs, urinalysis, LFTs
QRISK2 → screens for risk of cardiovascular disease.
QRISK < 10% management for hyperlipidaemia
lifestyle modifications
QRISK >= 10% management for hyperlipidaemia
atorvastatin 20mg
or simvastatin
or if they have IHD/PAD/cerebrovascular disease give atorvastatin 80mg
or if statin intolerant:
ezetimibe
in which pts is atorvastatin C/I
pregnant
Mech of action of ezetimibe
cholesterol absorption inhibitor
when should statins be taken to be most effective
last thing at night
when should statins be discontinued
if serum transaminase concentrations rise to and persist at 3 times the upper limit of the reference range
what is an important drug interaction of statins
with erythromycin/clarithromycin (macrolides) (can cause myopathy, increased likelihood of rhabdomyolysis)
which medication can cause both hypo and hyperthyroidism
amiodarone
list some side effects of amiodarone
hypothyroidism
hyperthyroidism
corneal deposits
Steven Johnsons syndrome
grey discolouration of the skin
liver failure
pneumonitis + pulmonary fibrosis
what type of medicine is aledronic acid
bisphosphonate
in which disease should bisphosphonates be avoided
advanced kidney disease
side effects of bisphosphonates
severe reflux disease
peptic ulceration
jaw necrosis
what med should be started in women with osteoperosis confirmed by DEXA scan or over 75yrs with 2+ risk factors for fracture / have had a previous fragility fracture
bisphosphonates eg aledronic acid
which side effect can spironolactone cause in men
gynaecomastia
symmetrical aches and pains
proximal muscle weakness
bone wearing fracture
waddling gait
likely diagnosis
osteomalacia
4 causes of osteomalacia
insufficient dietary calcium
vit D deficiency due to poor UV light exposure
CKD (causes low vit D which can cause low calcium)
malabsorption
what is osteopetrosis
defect in osteoclasts which means they cannot break down bone
results in denser bones and thickened bone cortices –> brittle bones
have stunted growth, bone pain, and bright hyper dense bones on imagining
joint and bone pain
stunted growth
in a child
likely diagnosis
rickets (childhood vit D deficiency)
bone pain
fractures
nausea
vomiting
constipation
high calcium, high PTH and ALP, low phosphate
likely diagnosis
hyperparathyroidism causing osteitis fibrosa csytica (excessive PTCH activates osteoclasts leading to increased bone resorption
weak deformed hyper vascular bones
normal calcium / phosphate / PTH
increased ALP
bone pain
symptoms in one bone only
likely diagnosis
pagets disease
–> is caused by deformed bone remodelling
MEN I symptoms
Parathyroid hyperplasia / adenoma
pituitary prolactinoma or GH secreting tumour (acromegaly)
Pancreas endocrine tumour (insulinoma, gastrinoma)
MEN IIa symptoms
thyroid cancer
parathyroid hyperplasia
bening and bilateral phaechromocytoma
MEN II b symptoms
Phaechromocytoma
Medullary thyroid cancer
mucosal neuroma
marfanoid appearance
tall stature
hypogonadism
gynaecomastia delayed puberty
likely diagnosis
Klinefelter’s syndrome (47 XXY)
what is the Rotterdam criteria for PCOS
2/3 of the below are needed for a diagnosis to be made
- presence of multiple ovarian cysts
- oligomenorrhoea or amnehorrhoea
- clinical/biochemical signs of hyperandrogenismeg acne/hirsutism/alopecia
oligomenhorroea
amenhorrea
galactorrrhoea
decreased libido
infertility
decreased bone mass
likely diagnosis
hyperprolcatinaemia
decsreased bone mass is due to decreases in oestrogen (hypogonadism)
oligomenhorrea
infertility
hirsutism
ambiguous genitalia
salt losing addisonian crisis
late onset congenital adrenal hyperplasia
(21 hydroxylate deficiency so can’t make cortisol and aldosterone, so make lots of androgens - high testosterone)
what diagnosis does recurrent chest infections and azoospermia point to
CF
(azoospermia is due to genesis of the vas deferens)
what effects does amiodarone withdrawal have on the thyroid
thyrotoxicosis
most common cause of hypopituitarism
pituitary adenoma
1st line investigation to confirm Addisons
measure cortisol.
if its low then do a short synthacten test - synthacten should stimulate cortisol production form the adrenal glands, this will not happen in Addisons
does parathyroid adenoma cause visible neck swelling
no
what is measured in the screening tests for medullary thyroid carcinoma
serum calcitonin
what is the effect of reduced Gh and gonadotrophin secretion on the bones
osteoporosis
1st line and definitive treatment for phaechromocytoma
alpha blockers eg Phenoxybenzamine
(then can add beta blocker to manage tachycardia/arrhythmias caused by alpha blockers, if needed)
then would do a phaechromocytoma resection (definitive management)
main side effect of phenoxybenzamine
reflex tachycardia
what is Waterhouse friderishcen syndrome (WS)
a severe, often fatal, disorder characterized by adrenal hemorrhage and failure, resulting from disseminated intravascular coagulation (DIC) triggered by a bacterial infection
presents initially with a nonspecific infection progressing into a macular, petechial, and subsequently purpuric rash, along with septic shock
most common cause of Waterhouse friderishcen syndrome (WS)
Neisseria meningitides
strep pneumonia
first line diagnostic test for phaechromocytoma
plasma free metenephrines
pt had cushings then had a bilateral adrenalectomy to treat it
they start to develop headaches and visual field defects
Nelsons syndrome
–> bilateral adrenalectomy causes loss of feedback to brain
therefore increased CRH release form hypothalamus
increased stimulation of pituitary causes enlargement and formation of pituitary adenoma
what is sick euthyroid syndrome
commonly seen during a period of illness
deranged low thyroid function tests despite normal functioning thyroid
will recover as the illness improves
which medications can cause a rise in prolactin levels
SSRI
cimetidine
BBs
how to manage galactorrhoea due to a certain drug, where the pt can’t stop taking the drug
co prescribe a dopamine agonist eg cabergoline to counteract the side effect - but manage with care bc cabergoline may reduce the effectiveness of the medication that they’re on
how to manage post partum thyroiditis
watch and wait
–> post part thyroiditis consists of hyperthyroidism then hypothyroidism. so if you give an antithyroid medication and then they become hypothyroid anyway, you could worsen things
what is made in each layer of the adrenal gland
Going deeper:
zona glomerulosa: aldosterone (salt)
zona fasciculata: glucocorticoids, cortisol (sugar)
zona reticularis: androgens (sex)
what medication is bromocriptine
dopamine agonist
what is li-fraumeni syndrome
a hereditary cancer predisposition syndrome associated with cancers such as leukaemia and sarcoma
first step in investigation/management of a pt with signs of cushings who is on long term steroid therapy currently
wean their steroid use
—> he first step would NOT be high/low dexamethasone suppression tests in this case as they would provide us with no further info, since she’s already on steroids and has high cortisol
treatment of subacute thyroiditis aka de quervains thyroiditis
supportive care and pain relief if needed (the condition will go from thyrotoxicosis, to hypothyroidism to euthryoidism)
antithyroid drugs dont work bc the thyrotoxicosis is due ti release of reframed hormones from the thyroid gland
at what age are boys with no pubertal development classed as having delayed puberty
14
which gene is associated with MEN 2a
RET gene
acute thyroiditis vs subacute thyroiditis
acute aka suppurative thyroiditis = caused by bacterial infection
presents with fever
presents quicker than subacute
rare
subacute thyroiditis aka de quervians = caused by viral infection
presents with painful neck, malaise
more common
initial screening test and result fro conns syndrome (primary hyperaldosteronism)
aldosterone to renin ratio
- elevated aldosterone causes sodium and therefore water retention. this increases renal perfusion, so inhibits renin secretion
high aldosterone, low renin
= high aldosterone: renin ratio
what is the aldosterone: renin ratio in primary vs secondary hyperaldosteronsim
high in primary eg conns syndrome
low in secondary - bc the aldosterone is elevated bc of the renin itself being elevated
best initial investigation in a young pt with poorly controlled HTN and hypokalaemia
aldosterone: renin ratio –> check for conns syndrome
what is the gold standard “challenge” test which is used ti clarify the diagnosis of hypopituitarism
insulin tolerance test
- stimulates hypoglycaemia wich aggravates a stress respinse
how does PTH act on bone to increase serum calcium levels
binds to osteoblasts which stimulate osteoclasts via porcine signalling
phaechromocytoma symptoms
episodic hypertension
palpitations
sweating
which hormones does a phaechromocytoma produce
it is a catecholamine producing tumour
potassium levels in conns syndrome vs Addisons
conns = hypokalaemia
Addisons = hyperkalaemia
which conditions are anti TPO antibodies found in
hashimotos or graves
how does PTh affect intestinal absorption of calcium and phosphate
increases intestinal absorption of both
carbimazole mech of action
inhibits TPO
palpitations, sweating, malignant hypertension
likely diagnosis
phaechromocytoma
which condition results in 2 or more specific neruoendocrine tumours (medullary thyroid cancer, phaechromocytoma, adenoma, parathyroid hyperplasia)
MEN 2a
what kind stature do MEN 2b sufferers have
marfanoid stature
what is the most likely cause of hyperprolactinamyia in young females with mental health problems
anti psychotics eg rsiperidone, tricyclic antidepressants, SSRIs, haloperidol
first line diagnosis test for cushings
overnight dexamethasone suppression test
first line investigation for delayed puberty
measure FSH and LH levels
what type of hypogonadism does kleinfleter’s cause
primary hypogonadism
what type of hypogonadism does kallman’s cause
secondary hypogonadism
what type of hypogonadism does cryptorchidism cause
primary hypogonadism
high TSH, normal T4
diagnosis
subclinical hypothyroidism
in what type of hyperaldosteronism are both renin and aldosterone raised
secondary hyperaldosteronism
causes of secondary hyperaldosteronism
nephrotic syndrome
liver cirrhosis
congestive heart failure
renal artery stenosis
young pt with high bp, sweating, headaches and anxiety
diagnosis
phaechormocytoma
an asymptomatic thyroid mass which is gradually getting larger in elderly pt
diagnosis
thryroid cyst / colloid nodule
what is involved on MEN1, MEN2a and MEN2b
MEN 1- (3 P’s) pancreas, parathyroid, pituitary
MEN 2A - (1M, 2P’s) Medullary thyroid cancer, pheochromocytoma, parathyroid
MEN 2B - (3M’s, 1P) Medullary thyroid cancer, Marfanoid, pheochromocytoma, mucosal neuroma
first line Tx for hypogonadism in men
testosterone therapy
first line investigation for hyperaldosteronism
aldosterone: renin ratio
(will be high in hyperaldosteronism)
gold standard for locating source of excess aldosterone in hyperaldosteronism
Selective adrenal venous sampling
treatment for hyperaldosteronism caused by bilateral adrenal disease
aldosterone antagonsists (Spironolactone, Eplerenone)
Then surgical resection
likely diagnosis for polyuria / polydipsia / headaches with osteoporosis
hyperaldosteronism
what is a well known heart complication of hyperthyroidism
atrial fibrillation
which condition is RET gene mutation associated with
MEN 2
male secondary sexual characteristics
the growth of pubic hair, and facial hair and the voice deepens
female secondary sexual characteristics
breasts develop, hips widen, and pubic hair begins to grow
long boy with small testicles, delayed puberty, gynaecomastia and no secondary sexual characteristics
likely diagnosis
kleinfelters
common cause of tingling after thyroid surgery
hypocalacemia - surgery may have affected the parathyroid glands
best investigation when looking for the cause of diabetes insipidus
MRI brain
(DI could be due to pituitary adenoma which is causing suppression of ADH secretion)
what is a neck lump which moves on swelling but not tongue protrusion suggestive of
a thyroid mass