Thyroid Flashcards
therapuetic effect Radioactive idoine
contraindicated
hyperfunction thyroid takes up and is ablated
most patients will develop lifelong hypothyroidism and require lifetime thyroid hormone
contraindicated in severes Grave’s orbitopathy, especially in smokers with eye involvement and in pregnancy
secondary hypothyroidism =
tertiary =
inadequate secretion or production of TSH from pituitary
inadequate secretion or production of TRH from hypothalamus
not always found in Grave’s patients, but a very specific finding
TSI thyroid stimualting imunnoglobulins
for secondary hyperthyroidism
TSH
T4
TSI
Thyroid uptake
Thyroid Scan
Treatment
TSH high or high normal
T4 high
TSI negative
Thyroid uptake NA
Thyroid Scan NA
Treatment pituitary surgery (pituitary adenoma)
TSH, T3/T4 levels in Graves
TSH low
high normal
mechanism+indication methmazole
side effects
hyperthyroidism
inhbits synthesis of thyroid hormes by blocking oxidation of iodine in the thyroid gland
reversible agranulocytosis
rash, joint pain, headache
driving force for thyrotoxicosis
thyroid stimualting immunoglobulin TSI
first step in differentiating between causes of primary hyperthyroidism
findings
radioiodine uptake/scan
Graves = high uptake, diffuse, bilateral
Hashimotos, granulomatous thyroiitis = low uptake
Toxic nodule or multinodular goiter = focused intense uptake
pathogenesis of lymphocytic (Hashimotos) thyroiditis
sensitization of lymphocytes to thryoglobulin, thyroid peroxidase, TASH receptor
cytokine release and inflammation ulitimately result in glandular destruction
in secondary/tertiary hypopthyroidism
TSH
Free T4, T3
thryroid peroxidase, thyroglobulin antibodies
TSH low or low normal
Free T4, T3 low
thryroid peroxidase, thyroglobulin antibodies negative
mxedema coma
severe hypothyroidism
multiorgan dysfunction
hypoventilation
hypotension
CNS changes
for toxic multinodal goiter or solitary toxic nodule
TSH
T4
TSI
Thyroid uptake
Thyroid Scan
Treatment
TSH low
T4 high
TSI negative
Thyroid uptake high
Thyroid Scan nodular, focal
Treatment - Methimazole, PTU, radioactive iodide, resection
Common symptoms hyperthyroidism
emotional lability
palpitations
weakness/fatigability
voracious apetit with weight loss
hyperkinesia, rapid speach
fine tremor
most skin
lid lag, state, proptosis
tachycardia, accentuated first heart sound, A-fib
heat intolerance
halflife Levothyroxine (T4)
liothyronine (T3)
Levothyroxine T4 - 6-7 days
LiothyronineT3 -
mechanism and indication propylthiouracil
adjunct for hyperthyroidism - refractory to methimazole or pregnant
inhibits synthesis of thyroid hormone by blocking oxiation of iodine, also partioanll inhibits periphera deiodination of T4 to T3
reversible agranulocytosis, hepatic failure
secondary thyroidititis due to
TSH secreting pituitary adenoma
Treatment for Hashimotos
Thyroid hormone (most often T4, levothyroxine)
(T3 liothyronine is also used, but has short half-life and requires rapid dosig)
pathophys for orbitopathy in Graves
sentization of T lymphocytes or T killer cells to TSH-R antigen found in thyroid follicular cells and orbital fibroblasts
most common causes of primary hyper thyroidism
Graves
toxic multinodal goiter
solitary toxic (follicular) adenoma
thyroitis - inflammation
therapeutic effects of iodie
inhibits hormone release
decreasses vascularity, size,, fragility of hyperplastic glands (pre-op utility)
first test for suspected thyroid disease,
if this is abnormal, high suspicion of ____ and follow-up test=
TSH
if abnormal, high suspicion for central process,
followed with free T4 testing
for thyroiditis
TSH
T4
TSI
Thyroid uptake
Thyroid Scan
Treatment
TSH low
T4 high
TSI negative
Thyroid uptake low
Thyroid ScanNA
Treatment - beta blockers, supportive care
other Rx for hyperthyroidism
Beta blocker (block adrenergic effects of thyroid hromone)
Lugols solution - oral iodine, Jod-basedow effect (hyperthyroidism following iodine admin)
Chlesturamine - binds thyroid hormone in gut during enterohepatic circulation
in Euthyroid…
TSH
Free T4, T3
thryroid peroxidase, thyroglobulin antibodies
TSH - normal
Free T4, T3 normal
thryroid peroxidase, thyroglobulin antibodies negative
in primary hypothyroidism
TSH
Free T4, T3
thryroid peroxidase, thyroglobulin antibodies
TSH elevated
Free T4, T3 low
thryroid peroxidase, thyroglobulin antibodies positive
for graves
TSH
T4
TSI
Thyroid uptake
Thyroid Scan
Treatment
TSH low
T4 high
TSI positive
Thyroid uptake high
Thyroid Scan diffuse, homogenous
Treatment - methimazole, PTU, radioactive iodine, resection
primary treatment options for Graves and other high uptake modalitiies of hyperthyroidism (toxic nodules)
Methimazole - inhibitor of thyroidal iodine organification,
propylthiouracil - inhibitor of thyroidal iodine organification,
(preferred in pregnancy, though hepatotoxicity possible)
Radioactive iodine
(generally preferred, longer dosing)
most common casue of primary hypothyroidsm
lymphocytic thyroditis (Hashimotos)
