Parathyroid

Question 1

position of superior parathyroid in relation to RLN

Answer 1

posterior and lateral to RLN

Question 2

position of inferior parathyroid in relation to RLN

Answer 2

anterior and medial

Question 3

embryologic origin of superior parathyroids

Answer 3

4th pharyngeal pouch

Question 4

embryologic origin of inferior parathyroids

Answer 4

3rd pharyngeal pouch

Question 5

are the superior or inferior parathyroids more variable in location?

Answer 5

inferior

Question 6

what cells release PTH? in response to what electrolyte derrangement?

Answer 6

the chief cells secrete PTH in response to low Ca

Question 7

what cells release calcitonin and what is the stimulus?

Answer 7

parafollicular c-cells in response to high Ca

Question 8

PTH effect on bone and kidney

Answer 8

bone - osteoclasts increase Ca and Phosphate reabsorption

kidneys - Ca reabsorption, inhibits phos and bicarb resorption (PHOS TRASHING HORMONE)

Question 9

how does vit D increase serum Ca

Answer 9

increased Ca and phos absorption in gut

Question 10

how does calcitonin decrease serum Ca in the bone and kidney?

Answer 10

bone - inhibits osteoclast bone resorption

Kidney - inhibits Ca and phos resorption

Question 11

MCC cause of hypercalcemia in the outpatient setting? inpatient?

Answer 11

outpatient - primary hyperparathyroidism

inpatient - cancer

Question 12

mechanism of hypercalcemia due to malignancy?

Answer 12

production of PTHrP

Question 13

Tx for hypercalcemic crisis

Answer 13

hydration and loop diuretics. avoid LR (Ca)

Question 14

MCC of primary hyperparathyroidism?

Answer 14

#1 adenoma
#2 hyperplasia 
#3 parathyroid cancer (men 1 and 2A)

Question 15

Lab pattern for hyperparathyroidism?

Answer 15

1. increased Ca (24 hr collection), decreased phos (except renal failure)
2. elevation of PTH
3. Cl:Phos >33:1
4. hypercalcuria, increased urinary cAMP

Question 16

Best study to localize parathyroid adenoma?

Answer 16

sestamibi with SPECT + US

Question 17

invasive study for adenoma localization?

Answer 17

angiography with venous sampling for PTH

Question 18

Tx for hyperparathyroidism?

Answer 18

parathyroidectomy

SYMPTOMATIC PATIENTS SHOULD UNDERGO SURGERY

Question 19

Tx for asymptomatic pt with hyperparathyroidism (5 instances)?

Answer 19

1. Ca elevation >1mg/dL over normal value
2. decreased Cr Clearance (<60 mL/min)
3. T score

Question 20

How do you confirm adequate resection of parathyroid adenoma?

Answer 20

need a >50% drop from baseline

Question 21

treatment of multiglandular parathyroid disease

Answer 21

subtotal parathyroidectomy (3.5 glands)
OR
Total thyroidectomy with SCM or brachioradialis reimplantation

Question 22

Who gets secondary hyperparathyroidism?

Answer 22

Renal failure patients

Question 23

Tx of secondary hyperparathyroidism?

Answer 23

Ca/VitD supplementation, renal diet, phos binders

Question 24

who gets tertiary hyperparathyroidism?

Answer 24

renal transplant patients who continue to have high PTH

Question 25

Tx of tertiary hyperparathyroidism

Answer 25

subtotal parathyroidectomy or subtotal with parathyroid autotransplantation

Question 26

Tx for parathyroid cancer

Answer 26

En bloc resection with ipsilateral thyroid and central neck dissection
chemorads is rarely effective

Question 27

metabolic derangement in hyperparathyroidism

Answer 27

hyperchloremic metabolic acidosis, hypophos

bicarb is excreted due to PTH

Question 28

elevated PTH, hypercalcemia, low urine Ca. what is Dx and Tx?

Answer 28

Dx - familial hypocalciuric hypercalcemia

Tx - nothing

Question 29

does inferior thyroid artery supply the parathyroid laterally or medially?

Answer 29

medially

Question 30

Where do you look for missing superior parathyroid gland?

Answer 30

retroesophageal space and open the carotid sheath

Question 31

where do you look for missing inferior parathyroid gland?

Answer 31

ipsilateral mediastinal thymus OR intrathyroid gland

Question 32

if four glands appear normal intraoperatively, but patient has elevated PTH - where do you look next?

Answer 32

thymus - hypersecreting supernumerary parathyroid gland

Question 33

MC location of missed gland?

Answer 33

in NORMAL anatomic position

Question 34

MC location of ectopic gland?

Answer 34

thymus