Endocrinology - Exam 2 (Thyroid, Calcitonin, PTH)

In a lab, if you see high levels of TSH what could this indicate? Low levels of TSH?

High = Hypothyroidism/Hashimoto's

Low = Hyperthyroidism/Graves

In a lab, if you see high levels of free T4 (fT4) or free T3 (fT3), what could this indicate? Low levels?

High = Hyperthyroidism

Low = Hypothyroidism

NOTE: HIGH T3 MAY be associated with hyper, but may not be.. for sure accurate for Hypo though...

In a lab, if you see altered levels of TPOAb, what could this indicate? (4)

Hashimoto's thyroiditis, Grave's disease, postpartum thyroiditis, thyroid inflammation

NOTE: TPO needed for synthesis of T3 or T4; TPOAb are antibodies present and indicating tissue damage

In a lab, if you see altered levels of TGAb, what does this indicate?

It is a marker for autoimmunity (cancer)

In a lab, if you see altered levels of TBI (TSHR/TSAb), what does this indicate?

Mimic TSH and bind to receptors, increasing production of TH

-- Hyperthyroidism (Graves)

In a lab, if you see altered levels of TBII, what does this indicate?

Block action of TSH to decrease production of TH

-- Hypothyroidism

In a lab, if you see altered rT3 levels, what does this indicate?

Reverse T3 production (evolutionary adaptation to protect thyroid during stress, physical trauma, injury, and illness)

What can be found on thyroid ultrasounds that can cause a disruption to the thyroid gland?

Nodules

What are the two most commonly checked hormones/antibodies in thyroid labs?

TSH

fT4

What three tests can indicate immune system attack on the thyroid if they are elevated?

TPO (thyroid peroxidase antibody)

TgAB (thyroglobulin antibody)

TRAb/TSHR/TSAb/TSI (Hyper)

What hormone can increase TBG?

Estrogen

T/F: Reference ranges are smaller ranges, but Optimal lab values are higher ranges?

FALSE

-- reference ranges may be WIDE

-- Optimal lab values are smaller more distinct ranges

NOTE: Listen to patient, if their symptoms don't match the lab, it could be subclinical!

Poor gut health ____________ thyroid function

Suppresses

When we have poor gut health, there will be a _______ in HCL, causing intestinal permeability, increased infection, increased inflammation, and increased leaky gut?

DECREASE

When leaky gut occurs, small amounts of partially digested food (toxins, antigens, bacterial fragments) pass through to system circulation. Where does this leaky gut occur?

Tight junctions

(occurs when tight junctions remain open)

When leaky gut occurs, it alarms the immune system, causing what to occur?

Develop antibodies to target "antibodies" and leads to food sensitivities

(continues and now at risk for autoimmunity)

Drugs, stress, alcohol, chemotherapy, radiation, surgeries, gut infections, imbalances, and challenging food/food sensitivities can influence what negatively?

Influence intestinal permeability (leaky gut) negatively

Glutamine, Polyphenols, Vit D, Zinc, and Probiotics can help maintain what?

Tight junction function

What are non-pathogenic microorganisms that reach the colon alive for beneficial health effects, with supplementation of this proved to benefit the thyroid function? Which two of these microorganisms is most often reduced in hypo or hyperthyroidism?

Probiotics

-- Lactobacillacaeae and Bifidobacteriaceae

Which micronutrient is essential for the synthesis of thyroid hormones, and is found in seafood, seaweed, iodized salts, and dairy products?

Iodine

What is the number 1 source of Iodine in the US?

Dairy

How can you tell if a patient needs Iodine supplements?

Have the patient do a 24-hour urine iodine test

-- 90% of the iodine should be secreted normally, so if this is case don't use; if its less, start slow but could indicate the thyroid needed it

Which micronutrient can cause decrease in synthesis of thyroid hormone when deficient, and can be found in Brazil nuts, seafood, organ meat, meat, cereal, grains, and dairy?

Selenium

Which micronutrient is essential for thyroid function, conversion, and homeostasis, and can be found in oysters, red meat and liver, pork, chicken, spinach, seafood, and fortified cereals?

Zinc

What micronutrient is essential for efficient iodine utilization and thyroid hormone synthesis, needed for conversion, and is found in lean meat, seafood, poultry, fortified cereal/breads, white beans, lentils, spinach, kidney beans, and peas?

Iron

What are lumps/bumps in the thyroid gland that are mostly benign, can arise at any age and are found by ultrasound?

Thyroid nodules

T/F: Thyroid nodules that can secrete TH (hyperthyroidism) are usually malignant.

FALSE

-- usually benign

Which type of thyroid nodules are stored forms of TH (colloid), resulting of degenrating thyroid adenomas

Cyst filled

Which type of thyroid nodules are more likely to be cancerous?

Solid nodules

What type of nodule cells are enlarged and increased reproduction rate of cells? Which are benign lesions?

Hyperplastic nodules

Adenomas

NOTE: when benign, left alone and watched, if not, treated

T/F: Thyroid cancers include both follicular epithelial cells & Parafollicular C cells?

TRUE

What are the two types of follicular epithelial cell thyroid cancers?

1) Differentiated thyroid cancer (DTC)

2) Undifferentiated thyroid cancer

What are the three types of Differentiated thyroid cancer (DTC)? Which is the most common? Second most common?

1) Papillary --> MC

2) Follicular --> 2nd MC

3) Hurthle cell (other)

Which DTC is a solid (MC), irregular, or cystic mass of follicular cells that grows slowly, usually developing in only 1 lobe of the thyroid, and spreads via the lymph?

Papillary Thyroid Cancer (PTC)

(Papillary Carcinomas, Papillary Adenocarcinomas)

NOTE: remember this is most common thyroid cancer

Who is most affected by Papillary Thyroid Cancer? What is the prognosis?

Women

30-50

(just know older women)

-- most individuals can be cured, rarely fatal

(accounts for 80% of all thyroid cancer)

Which DTC is more common in areas where people do not get enough iodine in the follicular cells, growing slowly, spreads to lungs/bones (but NOT through lymph)?

Follicular Thyroid Cancer (FTC)

(Follicular Carcinoma, Follicular Adenocarcinoma)

NOTE: 2nd most common thyroid cancer

Who is most commonly affected by Follicular Thyroid Cancer?

Women

>50

(Just know older women)

T/F: Follicular Thyroid cancer is more aggressive than Papillary Thyroid cancer.

TRUE

-- follicular has a not as good prognosis

Which DTC is a cancer of a oxyphil cells of the parathyroid gland that makes up only 3% of thyroid cancers, and is hard to find/treat?

Hurthle Cell Cancer

(Oxyphil cell carcinoma)

Which cancer is undifferentiated thyroid cancer (cancer cells do not look like normal thyroid cells) is the least common, very hard to control and hard to treat (aggressive) with a poor prognosis?

Anaplastic thyroid cancer

Who is most commonly affected by Anaplastic thyroid cancer?

Women

>60

(older women)

What is the cancer of parafollicular "C" cells that produces abnormally high levels of calcitonin, is slow growing, sometimes spreads in lymph nodes to lungs/liver, and is hard to find/treat?

Medullary Thyroid Cancer (MTC)

NOTE: remember C cells = thyroid (parafollicular) and Cheif cells = parathyroid; DONT CONFUSE

Which of the two types of medullary thyroid cancer makes up 8/10 cases, is seen in older adults, and only affects one lobe?

Sporadic MTC

Which of the two types of medullary thyroid cancer is inherited, develops early in childhood/early adulthood, can spread easily, usually encompasses several areas of both lobes, and is linked to an increase in other types of tissues?

Familial MTC

What are 6 symptoms of thyroid cancer?

1) Lumps/nodules

2) Enlarged lymph nodes

3) Cough/trouble breathing

4) Discomfort in neck

5) Swallowing issues

6) Hoarseness

What are substances (both natural/man-made) that are thought to cause endocrine disruption including pharmaceuticals, dioxin, polychlorinated biphenyls, DDT, pesticides, plasticizers, and are shown that thye may pose the greatest risk during prenatal and early postnatal development when organ/neural systems are forming?

Endocrine Disruptors

What disorders constitute one of the major endocrine problems in pregnancy, associated with adverse outcomes for mother and fetus?

thyroid disorders

During pregnancy, thyroid binding globulin factor (TBG) increases due to an increase in what two hormones?

Estrogen

Human Chorionic Gonadotropin hormone (hCG)

During pregnancy, with a higher level of TBG, is there more thyroid hormone bound to TBG or less bound? Is thyroid hormone active or inactive then?

More thlyroid hormone bound to TBG, so less free/unbound

-- free/unbound is active

During pregnancy, since the levels of free TH is transiently decreasing (due to binding to high levels of TBG), what will be increased in synthesis as a result? What feedback loop is this?

increased synthesis and secretion of thyroid hormones by thyroid gland

-- negative feedback loop

During pregnancy, as a consequence of all the above changes (increased TBG, low TH free, Increase secretion of TH), levels of total T4/T3 are ______, but levels of free physioligcally active is __________? What is this clinically called?

INCREASED

Normal

-- clinically called "Clinically euthyroid)

At what week does the baby start to make its own TH? Is this enough to sustain?

Make own at week 12 but doesn't make enough until 18-20

Hyperthyroidism in pregnancy can lead to what three things?

1) Graves' disease (1-4/1000 cases)

2) Hyperemesis gravidarum

3) thyroid nodules producing too much TH

NOTE: S/S same

T/F: Graves; may first appear during pregnancy, but if she already has Graves', there is no change.

FALSE

- Graves (if not had) can appear during pregnancy

-- if already have Graves', her symptoms could improve in second and third trimester, but often gets worse first few months after baby born

Why can Graves' symptoms for an individual improve in second/third trimesters? Why does it get worse first few months after baby born?

Some part of immune system less active later in pregnancy, so immune system makes less TSI

-- TSI levels go up again

What is severe nausea and vomiting leading to weight loss and dehydration during pregnancy? What causes this? Does it go away?

Hyperemesis

-- too high of levels of hCG early in pregnancy, causing too much TH production

-- usually goes away during second half of pregnancy

T/F: Graves' disease in the mother commonly affects the baby's thyroid, causing it to make too much TH.

FALSE

-- rarely this occurs

What are 7 possible maternal outcomes of hyperthyroidism during pregnancy?

1) Miscarriage

2) Preeclampsia

3) Preterm labor

4) Placental abruption

5) Hemorrhage

6) Thyroid storm

7) CHF

What are 5 fetal complications of hyperthyroidism during pregnancy?

1) Tachycardia

2) Early closure of skull

3) Poor weight gain

4) Irritability

5) Enlarged thyroid (difficulty breathing)

What is the treatment for hyperthyroidism during pregnancy?

If mild, no treatment

otherwise; antithyroid meds

(prevents too much TH getting to baby, lowers TH amount baby makes, lowest dose possible to prevent hypothyroidism)

What is a common cause of hypothyroidism in pregnancy?

Hashimoto's disease (2-3/1000)

NOTE: S/S same

What are 6 consequences of untreated hypothyroidism during pregnancy?

1) Miscarriage

2) Preeclampsia

3) Anemia

4) CHF

5) Low birth weight

6) Stillborn

What are two fetal complications due to low TH?

1) Low IQ

2) Problems with normal development

How is hypothyroidism treated during pregnancy? How does this change if the mother had hypothyroidism before the pregnancy vs developed during?

Hormone replacing medication

-- if hypothyroidism before: probably need to increase dose

-- test thyroid hormone levels every 4-6 weeks for first half of pregnancy and at least once after 30 weeks to see if adjustment needed

What is the inflammation of the thyroid that affects about 1 in 20 women during the first year after giving birth, causing sorted thyroid hormone to leak out of her thyroid gland? Who is this most common in?

Postpartum thyroiditis

-- MC in women with type 1 diabetes

Due to postpartum thyroiditis, the thyroid may be damaged, causing what to occur?

Underactive, causing hypothyroidism that may last up to a year after baby born

-- in some may not go away!

T/F: All women who have postpartum thyroiditis go through both the hyperthyroid phase and the hypothyroid phase.

FALSE

-- some go through one, other, or both phases

Since postpartum thyroiditis is an autoimmune condition like Hashimoto's disease, if a women gets postpartum thyroiditis, what can this indicate?

May have already had a mild form of autoimmune thyroiditis that flares up after she gave birth

What do parafollicular (C) cells of the thyroid secrete? In response to what?

Calcitonin

-- In response to HIGH levels of calcium in blood

What type of hormone is Calcitonin? What mechanism does it use?

Polypeptide hormone

-- Adenylyl cyclase mechanism (cAMP)

NOTE: Transmembrane receptor (outside cell)

What is the function of Calcitonin? (4)

LOWERS calcium (and phosphate) in plasma by:

1) Inhibiting activity of osteoclasts

2) Increase osteoblastic activity

3) Decreased calcium absorption in the intestines

4) Increase calcium lost in urine

What are 3 clinical uses for Calcitonin?

1) Osteoporosis treatment (if patient has adverse reactions to bisphosphonates which is a drug preventing loss of bone density)

2) Prevent osteoporosis fractures

3) Paget's disease

What condition is abnormal bone remodeling and bone growth where the bone is broken down and absorbed faster than normal bone remodeling, so the body speeds up the bone remodeling process and builds very weak and brittle bones?

Paget's Disease of the Bone

(Osteitis Deformans)

Who is most commonly affected by Paget's disease? What causes it?

50+

-- unknown causes (environmental, familial/genetic)

What are some symptoms of Paget's Disease?

- Pain in bone/spine

- Headaches

- Increased head size (ex: hats/caps arn't fitting anymore)

- Hearing loss

- Fractures

- Bowed legs

- Curvature of spine

- Nerve pressure

- Damage to cartilage (arthritis)

How is Paget's disease diagnosed?

History, exams, xrays, alkaline phosphatase blood test (high), bone scan

What is the treatment for Paget's disease (mild, serious, severe)

Some people do NOT need medication

-- if need medication to slow down breakdown of tissue, can take bisphosphates (or if these side effects too serious, can be given calcitonin)

-- Surgery (allow fractures to heal in proper positions, joint replacement, reduce nerve pressure)

Parathyroid glands (4) are located on the __________ side of the thyroid gland?

POSTERIOR

What cell type of the parathyroid hormone release parathyroid hormone (PTH)? What is this in response to?

Chief Cells

-- PTH released in response to LOW blood calcium levels

What mechanism does parathyroid hormone (PTH) use?

Adenylyl cyclase mechanism

What is the effect of PTH on blood calcium?

INCREASE plasma calcium level

What effects does PTH have on the Bones? (2)

Increase osteoclast & Inhibit osteoblast activity

-- increase blood calcium levels

What effect does PTH have on Kidneys? (3)

1) Inhibits phosphate reabsorption (in proximal convoluted tubule of the nephron)

2) Stimulate calcium reabsorption (in distal convoluted tubule of nephron)

3) Vitamin D activation (for SI) by activating 1 hydroxylase enzyme

What effect does PTH have on the Small intestine?

Triggers kidney to convert Vitamin D to active form, increasing intestinal calcium absorption from food (1 hydroxylase enzyme)

What is reabsorption?

Reabsorption is from renal tubules back to blood

What is the outside of the nephron? The inside of the nephron?

Outside = Bowmans capsule

Inside = Glomerulus

What are the 4 parts of the tubule associated with the nephron? What two parts does the PTH act on?

1) Proximal convoluted tubule --> PTH acts; inhibit Phosphate reabsorption

2) Loop of Henie

3) Distal convoluted tubule --> PTH acts; stimulates Calcium reabsorption

4) Collection duct

Bones act as calcium pools that release calcium into the blood stream when calcium levels are _____ due to _______ PTH levels?

Low calcium

High PTH

In the kidneys, PTH influences the balance of calcium removal or retained, so when PTH levels are ______, it signals kidneys to _______ phosphate reabsorption and ______ calcium reabsorption?

PTH levels are HIGH

Inhibit phosphate reabsorption

Stimulate calcium reabsorption

For the intestines, PTH will trigger the __________ to convert Vitamin D to an active form using __________ enzyme, which will _________ intestinal calcium absorption since Vitamin D receptors and calcium channel proteins are located in the SI cells.

Trigger Kidneys

1 hydroxylase Enzyme

INCREASE calcium absorption

What condition is too much calcium in the blood (hypercalcemia) due to enlargement of 1 or more of the parathyroid glands?

Primary Hyperparathyroidism

What is the treatment for Primary hyperparathyroidism?

Surgery (parathryoidectomy)

What condition first causes low calcium levels, and over time, increases PTH? What is a common example that causes this?

Secondary Hyperparathyroidism

-- ex: kidney failure

What is the treatment for Secondary Hyperparathyroidism?

Vitamin D

What condition is too little calcium in the blood (hypocalcemia)?

Hypoparathyroidism

What is the treatment for Hypoparathyroidism?

Oral calcium & Vitamin D

There are fewer than ____ cases of parathyroid cancer per year.

fewer than 100 cases