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Endocrine

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alkathryn's version from 2016-11-08 02:28

Anatomy

Question Answer
Pituitary is themaster gland
Endocrinerelease hormones into the bloodstream
Endocrine glands includepituitary gland, thyroid, parathryoid, adrenals, pancreas, ovaries, and testicles
Exocrinerelease into the skin or inside the mouth
Exocrine glands includesweat and salivary glands
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Pathology

Question Answer
Hyperthyroidism akathyrotoxicosis
Types of hyperthyroidismgrave's, plummer's, thyroid storm
Grave's akadiffuse toxic goiter
Goiter isenlarged thyroid
Grave's is an ___ caused byautoimmune, antibodies to TSH receptor
Grave's symptomsgoiter, exophthalmus (fluid pressure behind eyes), weight loss, fatigue, insomnia, palpitations, hair loss
Grave's treatmentsuppress T3 T4, RAI therapy, subtotal thyroidectomy, anti-thyroid medications
Plummer's akatoxic nodular goiter
Plummer's appears withsingle or multiple hyper functioning nodules "hot"
Plummer's symptomssame as Grave's, no exophthalmus
Plummer's treatmentsurgery, RAI therapy
Thyroid storm appears asacute conditions from untreated hyperthyroidism
Thyroid storm symptomshigh fever, tachycardia, respiratory distress
Thyroid storm treatmentRAI therapy (to suppress), anti-thyroid medication, beta blockers
Hypothyroidism isfunctional failure of thyroid gland, decreased T3 and T4 production
Hypothyroidism causesthyroiditis, thyroidectomy, iodine deficiency
Hypothyroidism symptomsfatigue, weakness, weight gain, cold intolerance
Types of hypothyroidismprimary, secondary, tertiary, cretinism, myxedema
Primary hypothyroidism is aniodine insufficiency
Primary hypothyroidism causehashimoto's (chronic thyroiditis)
Secondary hypothyroidism is aTSH deficiency
Secondary hypothyroidism occurs whenpituitary fails to deliver TSH to thyroid
Tertiary hypothyroidism is aTRH deficiency
Tertiary hypothyroidism occurs whenhypothalamus fails to deliver TRH to pituitary
Cretinism is acongenital condition caused by lack of thyroid hormones which leads to improper growth
Myxedema is alack of thyroid hormones in adults acquired from cretinism
Goiter isthyroid gland enlargement
Goiter is caused bydiet deficiency, increased TSH, thyroiditis
Goiter symptomsswollen neck, difficulty swallowing and breathing
Goiter treatmentthyroid hormones, surgery
Thyroiditis isinflammation of thyroid gland
Chronic thyroiditis ismost common cause of hypo, gradual thyroid failure
Subacute thyroiditis caused byviral infection
Subacute thyroiditis ispainful swollen gland with elevated thyroid hormone
Acute thyroiditis causebacteria
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Thyroid Cancers

Question Answer
Neoplasm akaadenoma, benign tumor, follicular adenoma
Neoplasm will appearnormal on scan
Types of cancerspapillary, follicular, medullary, anaplastic
Which cancer originates in C-cellsMedullary
Which cancers originate from follicular cellspapillary, follicular, anaplastic
Papillary is %80% of thyroid cancers
Papillary is ahormonal inactive tumor, slow growing
Anaplastic prognosisdeath within 1 year of diagnosis
Follicular is %15% of thyroid cancers
Medullary is %5%
Anaplastic is %<5%
Medullary causehereditary, can occur with pheochromocytoma
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Thyroid Uptake and Scan

Question Answer
Contraindictionsthyroid medications
Pt prepNPO 4-8 hours, no IV contrast (4-6 weeks), no thyroid medications
I-123 capsule dose100-300 uCi
All Iodine MOLactive transport
Which are trapped and organified by follicular cellsI-123 and I-131
I-131 capsule dose1-10 uCi
Pertechnetate forscanning only
Pertechnetate dose2-10 mCi IV
Pertechnetate MOLactive transport
Pertechnetate is _________ but not ___trapped, not organified
BEST collimatorPinhole
I-131 collimatorhigh or medium energy
Uptake equation(pt thyroid cpm - pt bkg) / ((std ct cpm X decay factor) - room bkg) ) x 100
I-131 scan time24 hours
I-123 scan time4-6 hours
Pertechnetate scan procedureinject, wait 15-20 mins, same as iodine
4-6 hour normal uptake5-20%
24 hour normal uptake10-35%
Graves appears as>35% at 24 hours, enlarged with uniform increase uptake
Plummer appears assingle or multiple nodules
Thyroid Ca appears assolitary "cold" nodule ( NOT ALWAYS )
Thyroiditis Hashimotos appears asenlarged gland, mottled areas
Thyroiditis acute or subacute appears aslittle or no uptake
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I-131 Whole Body Scan

Question Answer
Indicationseval of recurrent thyroid cancer, s/p total thyroidectomy residual scan, follow up
Contraindicationspt on thyroid meds, pregnancy
We want the patient in aHYPO state
Want TSH level>30-50 uU/ml
Perform scan onceTSH levels are reached
Thyrogen allows patients tostay on thyroid medications
Pt prepNPO 4 hours and 1 hr post inj, no IV contrast, laxative
RphxI-131 capsule
Dose3-5 mCi
Normal biodistribution seenstomach, small intestine, and bladder
Abnormalstar of David, lung or bones (mets)
Thyrogen is aglycoprotein
Thyrogenstimluates iodine uptake and organification, and synthesis and secretion of Tg T3 T4
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Parathyroid Imaging

Question Answer
Hypoparathyroidism symptomshypocalcemia, irregular heart
Hypoparathyroidism isinsufficient or absent secretion of PTH
Hyperparathyroidism isexcessive levels of PTH
Primary hyperparathyroidismone or more parathyroids, 80% = adenoma
Important cause of hypercalcemiarenal stones
Secondary hyperparathyroidism originatesoutside the parathyroid
Most common cause of secondary hyperparathyroidismrenal failure
Contraindicationpatient on calcium medications
Pt prepoff calcium meds for 1-4 weeks
Sestamibi dose15-30 mCi
Sestamibi MOLpassive transport
Thallium goes tothyroid and parathyroid
Tech goes tothyroid
MOL with pertechnetateactive transport
Thallium dose2-3 mCi
Tech dose5-10 mCi
Abnormals with subtraction methodareas of increased thallium within and outside normal thyroid tissue
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Adrenal Imaging

Question Answer
Pathologyhyperaldosteronism, cushing's disease, addison's disease, pheochromocytoma, neuroblastoma
Hyperaldosteronism akaConn's syndrome
Hyperaldosteronism is caused byaldosternoma
Cushing's disease isexcess production of cortisol
First degree cushing's due tohyper secretion of ACTH
Second degree cushing's due tosuprarenal tumor
Cushing's symptomsmoon face, buffalo hump, HTN fatigue, weakness
Addison's disease is adecreased cortisol levels
Addison's is caused byautoimmune adrenalitis or infections
Addison's symptomsfatigue, weight loss, nausea, hypoglycemia, hypotension
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Adrenal Cortex Imaging

Question Answer
rphxI-131 NP-59
Dose2 mCi
MOLactive transport
Pt PrepLugol's or perchlorate, laxatives
Image on day5, 6, 7
Normalboth adrenals visualized, liver, GB, colon
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Adrenal Medulla Imaging

Question Answer
Neuroendocrine tumors includemedullary thyroid cancer, paragangliomas, merkel cell skin tumors, small cell lung carcinoma
Indicationspheochromocytomas, neuroblastomas, neuroendocrine tumors
Pheochromocytoma is typicallybenign
Neuroblastoma is typicallymalignant, and fast growing abdominal mass
Pheo txsurgery
Neuroblast txsurgery, chemo, radiation. recurrent oftentimes
RphxI-131or I-123 mIBG
I-131 dose500 uCi - 1 mCi
I-123 dose10 mCi
Bioroutingurinary
MOLactive transport
Pt prepLugol's and up to 10 days after
I-131 mIBG imaging times24, 48, 72 hours. WB and statics
I-123 mIBG imaging times2-3, 24, 48 hours
Normal biodistributionpituitary, salivary glands, thyroid, heart, liver, and spleen
GB is seen withrenal failure
Normal uptake willdiminish in time
Abnormalsmets in skeleton heart lung lymph liver, areas of increased activity over time
Neuroblastoma appear inany sympathetic NS tissue location (abdomen -> bone and bone marrow)
False positivesurgical scars
False negativesmedications
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