Endocrine 2 Flashcards
thyroid hormone, in which 25% is secreted by thyroid, 80% formed by liver and kidney; is more free
T3
what is the onset of action of T3?
2-3 hours
thyroid hormones that is produced and mostly secreted by the thyroid, 99% bound to proteins
T4
what is the onset of action of T4?
2-3 days
why does T4 have more storage than T3?
T4 has high affinity for proteins
a disorder of low proteins will cause a disorder in what?
T3 and T4 levels
what is the main function of thyroid hormones?
glucose metabolism
a condition of low thyroid hormone that slows metabolism
hypothyroidism
failure of the thyroid gland itself
primary hypothyroidism
pituitary or hypothalamic disease causing reduced TSH/TRH
secondary hypothryoidism
what are 2 things that can cause hypothryoidism?
iodine deficiency
damaged thyroid due to radiation
condition that presents as swollen face, large tongue/fontanelle, distended abdomen, umbilical hernia, and scaley skin
congenital hypothyroidism
the most common type of acquired hypothyroidism, in which autoantibodies attack and destroy thyroid glands
hashimoto’s disease
what are the lab findings in hashimoto’s disease? (3)
decreased free T4
increased TPO antibody
increased TSH
what is enlargement of the thyroid gland called?
goiter
what is the treatment for hypothyroidism?
levothyroxine
what test should we start with when we suspect thyroid problems?
TSH
elevated thyroid hormones
hyperthyroidism
what are the lab findings in hyperthyroidism?
high T3/T4
low TSH
what is the metabolic consequences of excess thyroid hormones called?
thyrotoxicosis
what is the most common cause of hyperthyroidism?
grave’s disease
what are 3 symptoms seen in hyperthryoidism?
puffy eyes
anxiety
tremor
4 treatment options for hyperthyroidism
beta blockers
antithyroid meds
radioiodine therapy
surgery
an indirect measure of FT3/FT4
thyroid binding globulin (TBG)
which lab test will assess pituitary function and reflect long term thyroid status?
TSH
which test will reflect acute changes, is sensitive, and measures both free and bound thyroid hormone? (affected by TBG)
total T4
which test is an indicator of hyperthyroidism, and measures both bound and free thyroid hormone? (affected by TBG)
total T3
which test measures unbound T4 and is the most accurate reflection of thyrometabolic status?
free T4
what 2 things can cause low TBG levels?
high androgen
nephrotic syndrome
what 2 things can cause high TBG levels?
high estrogen
pregnancy
indirect measure of serum thyroid hormone binding capacity
T3 resin uptake
what is the relationship between T3 resin uptake and TBG binding sites?
inversely proportional
gives an indirect measure of free thyroid hormone levels
free T4 index
how would the free T4 index present in hyperthyroidism?
high
how would the free T4 index present in hypothyroidism?
low
what test would indicate autoimmune disorders if it is positive?
antithyroid antibodies
what increases circulating TBG and may increase the T4 dosage requirements in women with primary hypothyroidism?
estrogen/hormone therapy
what type of cushing’s syndrome is characterized by a tumor on the adrenal gland of the kidney?
adrenal cushing’s syndrome
what type of cushing’s syndrome is characterized by the pituitary producing too much ACTH?
pituitary cushing’s syndrome
what type of cushing’s syndrome is characterized by a tumor or mass releasing additional cortisol?
ectopic cushing’s syndrome
what are 4 manifestations of cushing’s syndrome?
moon face
buffalo hump
obesity
hypertension
what should I ask a patient if they present with striae?
recent steroid use
a test that measures the response of the adrenal glands to ACTH
dexamethasone suppression test
what would indicate an abnormal response to a dexamethasone suppression test?
no cortisol suppresion
what is the cause of an abnormal response to a dexamethasone suppression test?
primary overproduction - adrenal tumor
where is 90% of plasma cortisol?
bound to corticosteroid binding globulin (CBG)
where is CBG synthesized?
liver
what labs would be found in addison’s disease?
high ACTH
low cortisol
a disease characterized by hypo-adrenal function
addison’s disease
what does an elevated ACTH level indicate in an ACTH stimulation test?
primary adrenal insufficiency
what does a low/normal ACTH level indicate in an ACTH stimulation test?
secondary adrenal insufficiency
a disorder in which the pituitary gland produces insufficient ADH, so the kidneys make a lot of urine
diabetes insipidus
diabetes insipidus in which there is a decreased excretion of ADH due to damage to the hypothalamus or pituitary gland
central DI
diabetes insipidus in which the kidney is resistant to ADH
nephrogenic DI
what test can be used to determine type of diabetes insipidus?
water deprivation test
what kind of diabetes insipidus does our patient have if in a water deprivation test, there is no change in urine osmolality, but increased urine osmolality after given a vasopressor
central Di
what kind of diabetes insipidus does our patient have if in a water deprivation test, there is no change in urine osmolality, even after given a vasopressor
nephrogenic DI
what is the most often used medication for diabetes insipidus, especially in pregnancy?
desmopressin
