thyroid -general + cancer Flashcards
what hormones are involved in the hypothalamus-pituitary feedback loop
hypothalamus: thyrotropin (TRH) –> ant pit: TSH –> thyroid: T3 + T4 –> hypothalamus to inhibit TRH
what is the precursor for T3/4
thyroglobulin
role of iodide in production of T3/4
iodide oxidated –> iodine: converts thryobglubulin –> T3/4
what is the most abundant T3/4 hormone, what is more active
T4 - thyroxine more abundant // T3 more active
what converts T4 –> 3
liver + kidney
what proteins transport thyroid hormones around the body
TBG, TBPA, albumin
function thyroid hormones
increase: metabolism, growth, mood, cognition
function of calcitonin
inhibits osteoclasts + lowers Ca
benign causes thyroid nodules
multinodular goitre // adenoma // hashimoto // cyst
invx thyroid nodules
TFTS + ultrasonograpy
most –> least common thyroid cancer (5)
papillary –> follicular –> medullary –> anaplastic –> lymphoma
who usually gets papillary thyroid cancer
young females - good prognosis
how does papillary thyroid cancer metastasis
lymph
how does follicular thyroid cancer usually spread
blood
what group of conditions is medullary thyroid cancer assoc with
MEN 2
symptoms medullary thyroid
diarrhoea + flushed skin
tumour marker medullary thyroid cancer
calcitonin (arises from C cells)
symptoms/ features anaplastic thyroid cancer
pressure symptoms - SOB lying flat // old women // v unresponsive
what is thyroid lymphoma assoc with
hashimotos thyroiditis (hypothyroid)
invx thyroid cancer
USS + FNA // TSH
RF thyroid cancer
new nodule <20 or >50 // fast growing // male // 4cm // history radiation
mx papillary and follicular thyroid cancer
thyroidectomy followed with radioiodine
what marker is used to detect thyroid recurrence
thyroglobulin
complications of thyroidectomy (3)
damage to recurrent laryngeal (voice changes, hoarsness, swallowing, breathing) // bleeding + oedeoma –> obstructed airway // parathyroid –> hypocalcaemia
what happens to TBG, total thyroxine, and free thyroxine in pregnancy
TBG rises // raised bound thyroxine, no change in free T4
most common cause Thyrotoxicosis in pregnancy
graves
what can cause transient gestational hyperthyroid
HCG activates TSH
what semester does transient gestational hyperthyroid occur in
1st (HCG falls in tri 2 +3)
mx hyperthyroid pregnancy
1st tri = propylthiouracil // 2+3tri = carbimazole
what is contraindicated in thyroid mx in pregnancy
radioiodine
what should happen to thyroxin dose in hypothyroid pregnant women
at least double it in weeks 4-6
what are the stages of postpartum thyroiditis
hyper –> hypo –> normal
what antibody is common in postpartum thyroiditis
TPO
how does amiodarone cause amiodarone-induce HYPOthyroid
high iodine content
can amiodarone be continued in amiodarone-induced hypothyroidism
yes
features type 1 amiodarone-induced thyrotoxicosid
excess iodine –> excess thyroid hormone // goitre // hyperthyroid
mx type 1 amiodarone-induced thyrotoxicosid
carbimazole or potassium perchlorate
features type 2 amiodarone-induced thyrotoxicosid
destruction of thyroid –> no goitre
mx type 2 amiodarone-induced thyrotoxicosid
steroids
can amiodarone be continued in amiodarone-induced thyrotoxicosid
no
