Random Endo Facts

Question 1

Dopamine

Answer 1

= PIH = prolactin inhibitor hormone

-when released from the neurosecretory cells of the hypothalamus it works on the anterior pituitary to inhibit prolactin release

Question 2

Somatostatin

Answer 2

= GHIH = growth hormone inhibitory hormone

-when released from the neurosecretory cells of the hypothalamus it works on the anterior pituitary to inhibit GH release

Question 3

What causes Cushing’s disease?

Answer 3

ACTH secreting tumor

Question 4

Which endocrine gland is helpful for orientating oneself on a CT scan?

Answer 4

Pineal gland (secretes melatonin to regulate circadian rhythm). Is calcified (due to “brain sand”) and is therefore visible on CT

-lies posterior to the pituitary gland in the 3rd ventricle of the brain

Question 5

Which endocrine gland specifically accumulates fat w/ age

Answer 5

parathyroid gland- adiposity increases w/ age

Question 6

What is considered the major metabolic hormone?

Answer 6

T3

-b/c it targets virtually every tissue

Question 7

What is the worldwide most common cause of goiter?

Answer 7

idoine deficiency

Question 8

Why was cortisol named a glucocorticoid?

Answer 8

B/c it stimulates gluconeogenesis in the liver (get it…gluco…)

Question 9

Are deficiencies in the following hormones considered medical emergencies?

a) thyroid hormone
b) cortisol

Answer 9

Deficiency of thyroid hormone is not a medical emergency (not lethal short-term) while cortisol insufficiency is a medical emergency

Question 10

When is the growth hormone level highest?

Answer 10

At night while you’re sleeping

-so mother was right when she said if you don’t sleep it’ll stunt your growth!

Question 11

What is the correction factor for calcium levels when albumin is low?

Ex] what is the corrected serum calcium if calcium is originally measured at 6.6 mg/dl and albumin is measured at 2 g/dl

Answer 11

For every 1 g/dl drop in albumin, increase serum calcium by .8

Ex] Normal albumin is 4 g/dl => need to correct by a factor of 2 (.8)
=> corrected calcium is 6.6 + 1.6 = 8.2 mg/dl

Question 12

If they ask what an increase in CBG (cyroglobulin binding protein) concentration will do to serum free cortisol what answer are they looking for?

Answer 12

That long term it will not change the serum free cortisol => it will not affect the serum free cortisol

Question 13

What is PIP2 broken down into?

Answer 13

PIP2 –> IP3 + DAG

Question 14

Pretibial myxedema

Answer 14

Physical exam finding in Graves’ (autoimmune hyperthyroid)

Question 15

What chromosome is the MEN2A gene located on?

Answer 15

Chromosome 10

Question 16

What disorder is most commonly associated w/ SIADH?

Answer 16

SIADH = syndrome of inappropriate ADH secretion

Associated w/ small cell undifferentiated carcinoid of the thyroid

Question 17

What’s more common- parathyroid adenoma or parathyroid hyperplasia ?

Answer 17

Parathyroid adenoma causes 85% of primary hyperparathyroidism, while parathyroid hyperplasia is only about 10%

Question 18

What is the most common cause of primary hyperparathyroidism?

Answer 18

Parathyroid adenoma

-only in one gland (hence why adenoma and not hyperplasia)

Question 19

Which thyroid carcinoma has the best prognosis?

Answer 19

Papillary

Question 20

What is the most common cause of a midline cyst of the neck?

Answer 20

Thyroglossal duct cyst

-congenital, from a persistent thyroglossal duct

Question 21

Most common cardiac change seen in Graves’

Answer 21

Hypertrophied and dilated heart

Question 22

Adenoma of which endocrine organ is most commonly associated w/ pathologic fractures?

Answer 22

Parathyroid adenoma

-constantly high PTH => constant bone resorption

Question 23

Which functioning neoplasm of the thyroid is most likely to be functional?

Answer 23

Medullary carcinoma of the thyroid

-part of MEN2A and MEN2B

Question 24

When serum calcium is about what will PTH start getting secreted?

Answer 24

Below 7.5 mg/dl

Recall: normal serum calcium is 8.5-10.5 mg/dl

Question 25

When serum calcium is about what will calcitonin start getting secreted?

Answer 25

Above about 11 mg/dl

Question 26

If measured total calcium is normal, how can you estimate active calcium?

Answer 26

Divide it by two Ex] if calcium measured to be 9, you can estimate ionized calcium to be about 4.5 mg/dl

Question 27

Are the following symptoms of hypo- or hyper- calcemia a) tetany b) polyuria c) arrhythmia d) depression e) heart failure f) bradycardia g) muscle weakness h) muscle cramps i) paresthesias j) laryngospasm k) coma l) seizures

Answer 27

Hypo- vs. hyper- calcemia a) tetany = hypo b) polyuria = hyper (calcium causes osmotic diuresis) c) arrhythmia = hyper d) depression = hypo e) heart failure = hypo f) bradycardiac = hyper g) muscle weakness = hyper h) muscle cramps = hypo i) paresthesias (numbness/tingling) = hypo j) laryngospasm = hypo k) coma = hyper j) seizures = hypo

Question 28

Name two places where alk phos is secreted? How to distinguish origin?

Answer 28

Alk phos made by gall bladder (biliary) and bone. Measure GGT to distinguish location. High alk phos + high GGT = gall bladder damage High alk phos + low GGT = bone resorption occurring

Question 29

Cause of high PTH w/ high urinary Ca2+

Answer 29

primary hyperparathyroidism

Question 30

Cause of high PTH w/ low urinary Ca2+

Answer 30

familial hypocalciuric hypercalcemia -mutation in calcium sensor on chief (parathyroid) cell that requires a higher concentration of Ca2+ to inhibit PTH secretion

Question 31

Cause of low PTH w/ elevated PTHrP

Answer 31

Malignancy - tumor (often lung, breast, colon) metastasized that secretes PTHrp = PTH related protein - low PTH w/ high calcium

Question 32

Cause of low PTH w/ elevated calcidiol

Answer 32

excessive dietary intake of calcium or vitamin D | -vitamin D toxicity

Question 33

Cause of high PTH w/ elevated calcitriol yet normal calcidiol

Answer 33

Ectopic production of calcitriol | ex: granuloma from Tb, fungal infection, sarcoidosis

Question 34

What two medications are associated w/ causing hypercalcemia? Describe the mechanism?

Answer 34

Thiazide diuretics (HCTZ) and lithium -both cause hyperplasia of the parathryoid => increased PTH

Question 35

Possible change which serum electrolyte by thiazide diuretics?

Answer 35

Hypercalcemia by causing parathyroid hyperplasia => increased bone resorption

Question 36

Possible serum electrolyte side effect of lithium?

Answer 36

Hypercalcemia due to lithium causing parathyroid hyperplasia

Question 37

2 negative effects of primary hyperparathyroidism

Answer 37

- osteoporosis due to the constant bone resorption | - kidney stones due to the constantly high calcium

Question 38

What's the most common cause of primary hyperparathyroidism?

Answer 38

Parathryoid adenoma

Question 39

What is the best treatment for primary hyperparathyroidism?

Answer 39

Surgery! remove the adenoma or hyperplastic gland (first do imaging to localize which gland is the problem)

Question 40

Risk of osteoporosis from familial hypocalciuric hypercalcemia

Answer 40

Same as the rest of the population b/c unlike hypercalcemia due to primary hyperparathryoidism, the high serum calcium is not coming from bone resorption- instead it's coming from increased calcium reabsorption by the kidney

Question 41

Synthroid

Answer 41

= levothyroxine = L-tyroxine = T4 -medication given to replace thyroid hormone

Question 42

Chvostek's sign

Answer 42

Physical exam finding indicative of hypocalcemia

Question 43

Trousseau's sign

Answer 43

Physical exam finding indicative of hypocalcemia

Question 44

What is the first thing you do when you get a measurement of low serum calcium?

Answer 44

Test serum albumin, b/c if low than total calcium can be low w/o ionized calcium being low (so pt needs albumin replacement not Ca2+ replacement)

Question 45

What endocrine deficiency is consistent w/ hypocalcemia but normal phosphate levels

Answer 45

hypoparathyroidism -PTH doesn't increase phosphate levels

Question 46

What is the most likely cause of hypocalcemia with: - low phosphate - high PTH

Answer 46

vitamin D deficiency