CNM - Endocrine (dugan)

What organs and glands are there in the endocrine system?

pineal gland, pituitary gland, hypothalamus, thyroid, parathyroid, thymus, pancreas, adrenal gland, ovary, testicle, placenta

Describe the location of the thyroid

front of neck below the larynx of two 2in lobes beside the trachea

How is the thyroid connected?

by the isthmus

What cells make up the thryoid?

follicular cells and parafollicular cells

What are the functions of the follicular cell?

secrete iodine containing hormones called thyroxine (T4) and triiodothyronine (T3)

What is needed to produce thyroid hormones?

iodine

What is the function of parafollicular cells?

secrete the hormone calcitonin

What organs/glands produce hormones for the endocrine system?

hypothalamus, thyroid, parathyroid, adrenal, pituitary gland, pancreas

What hormones does the hypothalamus secrete?

TRH, CRH, GHRH, Dopamine, Somatostatin, Vasopressin

What hormones does the thyroid and parathyroid secrete?

T3, T4, Calcitonin, PTH

What hormones does the adrenal secrete?

androgens, glucocorticoids, adrenaline, noradrenaline

What hormones does the pituitary gland secrete?

GH, TSH, ACTH, FSH, MSH, LH, Prolactin, Oxytocin, Vasopressin

What hormones does the pancreas secrete?

insulin, glucagon, somatostatin

What are the thyroids function?

regulates bodys metabolism and calcium balance, converts iodine into T3 and T4 with the help of tyrosine

What controls the thyroid gland?

pituitary gland

What happens when T3 and T4 levels drop?

TSH is released from pituitary gland

How is T3 formed?

when T4 is converted to T3 (80% formed in the body tissues by removing iodine from thyroxine)

What is the purpose of T3 and T4?

stimulate every tissue in the body to produce proteins and increase amount of oxygen used by cells

What does calcitonin hormone work together with? Why?

the parathyroid hormone to regulate calcium levels in body

What is TSH controlled by?

hypothalamus

What is tyrosine a building block for?

neurotransmitters (epinephrine, norepinephrine, dopamine)

What can tyrosine be taken as a supplement for?

depression, ADD, ADHD, narcolepsy

What is purpose of tyrosine?

melanin, helps regulate and make hormones (adrenal, thyroid, pituitary glands), and is involved in the structure of majority of proteins in the body

Describe the parathyroid

four small oval shaped glands on back of thyroid gland

What are the functions of the parathyroid hormone?

regulates calcium levels in blood, absorption of food in intestines, conservation of calcium by the kidneys

How are calcium levels kept at homeostasis?

if calcium levels rise thyroid releases calcitonin to bring blood calcium levels back down, and if calcium levels fall parathyroid releases TSH and blood calcium levels rise

Describe the adrenals

also known as suprarenal glands, have two parts cortex and medulla

What do the adrenal glands work with?

hypothalamus and pituitary gland

What does the hypothalmus produce?

corticotropin hormones (stimulate pituitary gland)

What does the pituitary gland produce?

corticotropin hormones (stimulate adrenal glands to produce corticosteroids)

T/F The adrenal cortex and medulla perform the same task

False

What are the effects of adrenal cortex secretions?

metabolism, chemicals in blood, body characteristics

What do corticosteroids do?

controls fats and carbs

What do aldosterone hormones do?

maintains blood volume and blood pressure

What do androgenic steroids do?

development of male characteristics

What hormones are secreted by the adrenal medulla and purpose?

epinephrine and norepinephrine, and helps cope with physical and emotional stress

What does epinephrine do?

increase heart rate, blood flow to muscles and brain, relaxation of smooth muscles, conversion of glycogen to glucose in the liver

What does norepinephrine do?

strong vasoconstrictor and increases BP

Describe the lacrimal glands

small almond shaped structure that produces tears

What are the lacrimal glands function?

forms tears and conveys them through the lacrimal duct to the eye

Explain the negative feed back starting with iodine

iodine is absorbed by the thyroid gland, thyroid gland produces with T3 and T4, T3 and T4 levels affect hypothalamus which secretes TRF, TRF stimulates the pituitary gland to secrete TSH

What is hypothyroidism?

low circulating hormone levels, increased TSH production and release of T3 and T4

What is hyperthyroidism?

high circulating hormone levels, decreases TSH production

What are the normal T3 levels? (serum concentration, half life, daily turnover, and totaly daily production)

0.1-0.2mcg/100ml, 1.5days, 50%, 50mcg

What are the normal T4 levels? (serum concentration, half life, daily turnover, and totaly daily production)

4-11mcg/100ml, 6-7days, 10%, 100mcg

What is addison's disease?

endocrine or hormonal disorder that occurs in all age groups affecting weight, muscle weakness, fatigue, low BP, darkening skin

When adrenal glands don't produce enough cortisol this causes which disease?

addisons disease

What is the treatment for addisons disease?

hydrocortisone, prednisone, methylprednisolone, dexamethasone

What is the most important hormone to help the body respond to stress?

cortisol

What does a lacrimal duct obstruction cause?

excess treating similar to conjunctivitis

What is the treatment to lacrimal duct obstruction?

surgical correction

What is the Nuke Med procedure?

Tc-99m pertechnetate drop in conjunctival space and image to see the passage of material into the nose

What is levothyroxine/synthroid?

used to treat hypothyroidism and replaces the hormone usually produced by thyroid gland

T/F Levothyroxine is taken for life

true

What type of radiopharms can be used in a thyroid uptake and scan? (doses as well as radpharms)

200µCi 1-123 sodium iodide in capsule, 15µCi 1-131 sodium iodide capsule, or 8mCi Tc-99m Pertechnetate

What is the energy and half-life of I-123?

159keV and 13hrs

What is the energy and half-life of I-131?

364keV and 8 days

What questions need to be asked prior to a thyroid uptake scan?

pregnant/nursing, medications, x-ray contrast, radionuclide studies, only clear liquids 2hrs prior

What is the uptake procedure of a thyroid scan?

measure capsule in dose calibrator and the probe initially, then take measurements of background (thigh) and counts at neck 4-6hrs after capsule ingested

What is the thyroid % uptake equation?

(neck counts - thigh counts)/(background - capsule) * 100 (bkg-cap aka count of standard)

What is normal uptake at 4hrs of I-123?

10-15%

What is normal uptake at 24hrs of I-123?

15-30%

Explain the thyroid uptake scan portion?

after uptake then patient will lay supine with neck hyper extended, take a marker image ANT, then with pinhole ANT, 30 degree RAO and LAO

ANT with marker

What image view is this?

RAO

What image view is this?

LAO

What image view is this?

Ant

What image view is this?

What would a cold nodule on a thyroid uptake scan mean?

non-functioning, benign adenomas, cysts, hematomas, inflammatory

What would a hot nodule on a thyroid uptake scan mean?

benign

What is used to confirm a cystic vs solid mass on the thyroid?

ultrasound or Bx

Is it likely cancer if we see a cold nodule on a uptake scan?

no, only 20% of the time is it a cold nodule

What does this image indicate?

cold nodule

Grave's

What does this image indicate?

toxic multinodular (hot and cold nodules)

What does this image indicate?

What does this image indicate?

hot nodule

What does this image indicate?

autonomous nodule

What does this image indicate?

thyroiditis

What is the purpose of Tc-99m thyroid scan?

establishes position, size, contour, function, and presence of gland

Is I-123 cyclotron or generator produce?

cyclotron

What is the procedure for a Tc-99m thyroid scan?

image 15-20mins post injection, with pinhole take ANT, RAO, LAO images 10mins with hyper extended

When would we do a flow study with a blood pool?

differentiate between cystic vs solid masses

What is the purpose of a newborn thyroid scan?

detection of lingual thyroid or congenital hypothyroidism

What is the patient prep for a newborn thyroid scan?

NPO 3hrs prior to scan

What is the radiopharm and dose for a newborn thyroid scan?

150µCi/kg TcO4

What images are taken for a newborn thyroid scan?

5 min pinhole ANT with nose and chin markers and a Laterals with markers

What is the protocol/forms for an I-131 therapy for hyperthyroidism?

info packets, consent for therapy, I-123 or I-131 therapy, informed consent, and a written directive

What are the purpose for WB scans when concerning thyroid?

determine if there are metastatic lesions and dose for therapy (before) and determine any smaller metastatic lesions and how effective therapy was (after)

What is the patient prep for a WB radioiodine scan?

scheduled after thyroidectomy, off any thyroid replacement drugs with TSH>30 OR 2 thyrogen injections prior to receiving therapy dose

What is the dose and radiopharm for a WB radioiodine scan?

3-4mCi of I-123 or I-131

Explain procedure after patient receives capsule of I-123 or I-131 for therapy

delay scan 24hrs (48hrs if I-131) and then post therapy images 7 days out

What images are taken for WB thyroid scan?

WB, uptake, spot of neck and SPECT-CT of neck/chest

What is thyrogen?

synthetic form of TSH and can be used as a routine check up for thyroid cancer

When are injections of thyrogen given?

IM at doctors office or here 2 consecutive days prior to administration of diagnostic iodine dose

What does TSH cause thyroid cells to do?

make thyroglobulin and release it into bloodstream and absorb radioactive iodine (only well differentiated cancer cells will have uptake or residual thyroid cells)

What causes the sensitivity of a thyroid scan to increase?

receiving thyrogen

What are some side effects of thyrogen?

mild nausea, headache, weakness, vomiting, itching or rash around injection site

What does a blood test, thyroglobulin, or Tg test measure

levels of thyroglobulin in bloodstream and determines if any thyroid cells are producing thyroglobulin

If blood test, thyroglobulin or Tg test come back positive, what does this indicate?

wholebody scan for positive thyroid tissue I-131 therapy likely to be prescribed

Label which side is I-123 and I-131 Diagnostic Image

left I-123, right I-131

How would we do an I-123 Mets imaging?

image 24hrs post I-123 dose, uptake at 24hrs (neck, thigh, and chest), then image