Endocrinology Flashcards
what does hypokalaemia associated with hypertension indicate?
primary hyperaldosteronism
which 2 tests are most commonly used to diagnose cushing’s? which is the most sensitive?
overnight dexamethasone suppression test (most sensitive)
24h urinary free cortisol
2 conditions that can cause diabetes
chronic pancreatitis
haemochromatosis
damage pancreas’s insulin-producing cells
name a drug that causes raised glucose levels
glucocorticoids
what is a glucose tolerance test?
fasting BG taken, then 75g glucose taken
2hrs later - BG taken again
diagnosis of DM by blood glucose
if symptomatic:
fasting glucose of 7+
random glucose of 11+ (or after 75g OGTT)
if asymptomatic, these must apply on 2 occasions
6.1-6.9 fasting - prediabetes
HbA1c in diagnosis of DM
what can cause misleading results?
42-47 - prediabetes
48+ - diagnostic
less than 48 doesn’t exclude
if asymptomatic, repeat test to confirm
increased red cell turnover - misleading
how does metformin work?
increases insulin sensitivity
decreases hepatic gluconeogenesis
2 SEs metformin
GI upset
lactic acidosis
when can you not use metformin?
eGFR < 30
what type of drug is gliclazide?
sulfonylurea
how do sulfonylureas (gliclazide) work?
stimulate beta cells to produce insulin
3 SEs of sulfonylureas (eg gliclazide)
hypoglycaemia
weight gain
hyponatraemia
3 SEs of thiazolidinediones
name the thiazolidinedione used
weight gain
fluid retention
liver impairment
pioglitazone
how to distinguish DM 1 from other types?
c-peptide - low in DM1
DVLA - rules if on insulin/sulfonylureas for HGV drivers
no severe hypo in last year
monitor BG 2x daily
DVLA - rules for drivers on insulin (group 1)
not more than 1 hypo needing others’ help in last year
3 things that can precipitate DKA
infection
missed insulin
MI
management of DKA
0.9% saline 1L over 1h
then IV insulin infusion 0.1u/kg/h
once BG <15: 5% dextrose
correction of hypokalaemia
what are the 2 roles of ADH?
regulates tonicity of body fluids:
makes kidneys reabsorb water to return to blood → concentrates urine + reduces its volume
constricts arterioles → increased peripheral vascular resistance → BP raised
how does SIADH present on blood + urine tests?
hyponatraemia
low plasma osmolality
high urine osmolality
what endocrine effect can small cell lung cancer have?
SIADH
BP target in diabetes
140/80
or 130/80 if end organ damage
diagnosis of follicular thyroid carcinoma
USS + FNA + hemithyroidectomy
papillar/follicular thyroid cancer - mgmt + monitoring
total thyroidectomy
then radioiodine
yearly thyroglobulin levels
patients on steroids long-term - what to do with dose if get intercurrent illness?
double it
what effects can glucocorticoids have on the eye?
glaucoma
cataracts
2 SEs of mineralocorticoids (fludrocortisone + hydrocortisone)
fluid retention
HTN
how does pioglitazone (a thiazonidiledione) work?
inreases insulin sensitivity (reduces peripheral insulin resistance)
what is an adverse effect of thiazides?
hypercalcaemia
what are the commonest causes of hypercalcaemia?
primary hyperPTH
malignancy (due to variety of processes eg bone mets, myeloma)
what is one finding of myeloma on bloods?
hypercalcaemia
how can hyperPTH present on bloods?
hypercalcaemia
how can malignancy present on bloods?
hypercalcaemia
what kind of drug is sitagliptin?
DPP-4 inhibitor
what is a SE of exenatide?
weight loss
what is deep, laboured breathing a sign of?
DKA or metabolic acidosis
Kussmaul’s breathing - inhales excess CO2 to compensate
whats the main issue in addisons?
little/no endogenous steroid production
what happens to cortisol levels when ill?
increase
addisons pt unwell - what to do with hydrocortisone + fludrocortisone doses?
same fludrocortisone
double hydrocortisone
addisons - management
fludrocortisone + hydrocortisone
what are the 4 insulin antagonists?
adrenaline
glucagon
growth hormone
cortisol
(is this why growing, stress, illness can precipitate DKA?)
DKA - metabolic pathway
consider as fats + sugars:
increased stress hormones + reduced insulin cause:
1) lipolysis -> ketoacidosis -> kussmaul, ketone breath, negative inotropism
2) hyperglycaemia -> osmotic diuresis -> dehydration, K depletion + renal impairment
what causes the hypokalaemia in DKA?
1) osmotic diuresis
2) RAS activated to hold onto Na + fluid but causes you to excrete K. means total body K always low but serum K sometimes normal/high - ‘potassium paradox’ - prerenal AKI
explain a normal-high K in DKA
1) acidosis - H+ in cells forces K+ out to maintain intracellular cation balance
2) no insulin - no K+ uptake until insulin replaced - then sudden drop
3) prerenal AKI - oliguria with failure of K+ excretion
4 causes of macroglossia
acromegaly
down’s
amyloid
congenital hypothyroidism
euthyroid with neck lump - what is it?
multinodular goitre - commonest large goitre
rarely can go thyrotoxic (toxic multi nodular goitre
what doesn’t take up radioiodine?
thyroid cancer or cyst
multinodular goitre - indications for surgery
cosmetic
local structure compression eg voice change, stridor
what are pemberton’s test + sign?
test for retrosternal goitre - raise arms + pink face from SVC obstruction, can cause stridor
neurofibromatosis - inheritance?
autosomal dominant condition
neurofibromatosis - features
axillary freckling
cafe au lait spots
type 2 - acoustic neuroma
