Investigating endocrine Flashcards
what are three types of endocrine hormone and give examples
peptide hormones from pituitary - PTH, ACTH, TSH
steroid hormones - testosterone, cortisol
tyrosine based hormones - T4, thyroxine
how do TBG affect thyroid function tests
thyroxine binding globulin - causes changes in levels of free hormone
what do these measurements mean TSH low fT4 low TSH high fT4 low TSH low fT4 high TSH high fT4 high
pituitary failure = secondary hypothyroidism
unresponsive thyroid to TSH = primary hyporthyroidism
not by stimulus - thyroid gland overproduction = primary hyperthyroidism
p[pituitary overload = secondary hyperthyroidism
what is TSH frontline testing and why is it advantageous
cheaper
measure TSH if normal leave but can be elevated or decreased then measure free T4 levels for different causes
why is it sometimes a mistake that a TSH test comes back at normal level
they can have secondary hypothyroidism - have low fT4
what is sick euthyroid disease
non-thyroidal illness
illness can suppress TSH and reduce levels of TBG hence increasing thyroid hormone levels but TT3 is normal
how often do you repeat thyroid function tests
healthy = every 3 years
hyperthyroid - every 1-2 months
hypothyroid = every 2-3 months
what can cause inaccuracies of thyroid function testing
interference by immunoassay which alters results
what are the two types of phaeochromocytomas
adrenal medullary tumours
phaechromocyomas in adults
neuroblastoma in children
what is a phaechromocytoma, clinical features and diagnosis
tumour of neuroendocrine chromatin cells in adrenal medulla - produces extra catecholamines
hypertension, sweating pallor headaches abdominal pain
diagnosis = higher plasmametanphrines - metabolite of catecholamines raised across the day
what is whipple triad
definition of hypoglycaemia
low plasma glucose
signs and symptoms of hypoglycaemia
relief of symptoms with IV glucose
what are three causes of hypoglycaemia
diabetets - most common cause in adults
exogenous - alcohol
endogenous - insulinoma - insulin secreting tumour in islet of langerhams
what are some give away signs for insulinoma
high levels of c peptide
high insulin and low blood sugar
what are the features of bushings syndrome
obesity, central weight gain thin bruising of skin hypertension, impotence muscle weakness back pain from osteoporosis depression and anxiety
what is the mechanism of bushings syndrome
corticotropic releasing hormone from hypothalamus,us which acts on pituitary to make ACTH to make glucocorticoids such as cortisol
