Fiser ABSITE Ch. 23 Parathyroid

Question 1

Where do the superior parathyroid originate? and inferior?

Answer 1

4th pharyngeal pouch, 3rd pharyngeal pouch

Question 2

Where are the superior parathyroids in relation to the RLNs? and the inferior?

Answer 2

lateral, medial

Question 3

Where are the superior parathyroids in relation to the inferior thyroid artery? and inferior parathyroids?

Answer 3

above, below

Question 4

What is the blood supply to the parathyroids?

Answer 4

inferior thyroid artery

Question 5

What is the most common ectopic site for parathyroids?

Answer 5

tail of the thymus

Question 6

What is a normal Ca level range?

Answer 6

8.5-10.5

Question 7

What is a normal PTH level range?

Answer 7

5-40

Question 8

What is the most common cause of hypoparathyroidism?

Answer 8

previous thyroid surgery

Question 9

What is the name form bone lesions from Ca resorption; characteristic of hyperparathyroidism?

Answer 9

Osteitis firbrosa cystica (brown tumors)

Question 10

Indications for parathyroid surgery include symptomatic disease or asymptomatic disease with Ca above what level?

Answer 10

13

Question 11

What percentage of pts with hyperparathyroid have single adenoma? multiple adenomas? diffuse hyperplasia?

Answer 11

single adenoma 80%
multiple adenomas 4%
diffuse hyperplasia 15%

Question 12

Hyperparathyroidism in pregnancy carries a risk of still birth. In what trimester do you operate?

Answer 12

2nd

Question 13

What is the half-life of PTH?

Answer 13

10 minutes

Question 14

What should be done if parathyroid CA is found?

Answer 14

radical parathyroidectomy and take ipsilateral thyroid

Question 15

What are the three causes of postop hypocalcemia after parathyroid surgery?

Answer 15

bone hunger, hypomagnesmia, failure of parathyroid remnant or graft

Question 16

Hypocalcemia postop after parathyroid surgery. What will the levels of PTH and HCO3- be if the cause is bone hunger? and what if it is aparathyroidism?

Answer 16

Bone hunger - normal PTH, decreased HCO3_ Aparathyroidism - decreased PTH, normal HCO3_

Question 17

What is the study that is used in hyperparathyroidism that is good for picking up adenomas and ectopic glands but not 4-gland hyperplasia?

Answer 17

sestamibi-technetium-99

Question 18

What is the most common indication for surgery in secondary hyperparathyroidism?

Answer 18

bone pain

Question 19

What diagnosis should you consider if pt has Ca 9-11, normal PTH (30-60), _ urine Ca?

Answer 19

Familial hypercalcemic hypocalciuria

Question 20

What is the cause of familial hypercalcemic hypocalciuria?

Answer 20

Caused by defect in PTH receptor in distal convoluted tubule of the kidney that causes _ resorption of Ca

Question 21

What is the tx for familial hypercalcemic hypocalciuria?

Answer 21

Nothing, no parathyroidectomy because Ca generally not that high

Question 22

What is the most common location for metastases of parathyroid cancer?

Answer 22

the lung

Question 23

List the MEN syndromes and components?

Answer 23

MEN I: parathyroid hyperplasia, pancreatic islet cell tumors, pituitary adenomas
MEN IIa: parathyroid hyperplasia, pheochromocytoma, medullary CA of the thyroid
MEN IIb: pheochromocytomas, medullary CA of thyroid, mucosal neuromas, marfan’s habitus

Question 24

Name the drug used in the management of hypercalcemia that inhibits osteoclasts (used with malignancies or failure of conventional treatment); has hematologic, liver, and renal side effects.

Answer 24

Mithramycin

Question 25

When breast CA metastases to bone, what causes hypercalcemia?

Answer 25

release of PTHrp

Question 26

What hormone is responsible for duct development of the breast? and lobular development? and what hormone synergizes those two?

Answer 26

estrogen, progesterone, prolactin