PARATHYROID

Question 1

Can you palpate parathyroid adenoma or hyperplasia?

Answer 1

rarely.

Question 2

Dx pseudohypoPTH

Answer 2

target tissues resistant to PTH -> low Ca, elevated P + defect in skeletal growth and development

Question 3

Gene pseudohypoPTH

Answer 3

GNAS1 mutation -> encodes GCPR alpha-subunit; mutation results LOF in signaling pathway -> kidney does not respond to PTH

Question 4

Indication for surgery of asymptomatic hyperPTH

Answer 4

• serum Ca >1mg/dL
• CrCl <60
• osteoporosis (T-score <2.5)
• poor access care or f/u
• age <50

Question 5

MC sxs hyperCa

Answer 5

nephrolithiasis

Question 6

MC aberrant locations of superior parathyroid

Answer 6

• retroesophageal space

- carotid sheath

Question 7

MC aberrant location of inferior parathyroid

Answer 7

• ipsilateral mediastinal thymus

Question 8

If 4 normal glands, but still hyperPTH… think? MC located…?

Answer 8

hypersecreting suprannumery hyperPTH gland; MC located in thymus

Question 9

MC location missed parathyroid gland

Answer 9

normal anatomic location

Question 10

MC location ectopic parathyroid gland

Answer 10

thymus

Question 11

MCC malignancy associated w/ hyperCa

Answer 11

SCC (PTHrH), then breast cancer

Question 12

Mgmt parathyroid cancer

Answer 12

en-block resection w/ ipsilateral thyroid and central neck dissection

Question 13

Mgmt recurrent or widely metastatic parathyroid cancer

Answer 13

palliative lowering surgery + Ca-lowering drugs

Question 14

Electrolyte disturbances of hyperPTH

Answer 14

hyperCl metabolic acidosis (Cl:P >33; phos and bicarb excretion in kidneys)

Question 15

Mgmt secondary hyperPTH

Answer 15

• hyperP: phosphate binders + dietary mod
• Ca supp
• correction of acidosis
• vitD supp
• surgery indicated only for…

Question 16

When more likely to have 4-gland involvement for hyperPTH?

Answer 16

MEN pts and pts w/ lithium-induced HPT

Question 17

Cinacalcet

Answer 17

directly inhibit PTH in pts with chronic renal failure

Question 18

Does bone mineral density improve after parathyroidectomy?

Answer 18

YES.

Question 19

What type and location of bone does primary hyperPTH typically affect?

Answer 19

cortical bone > cancellous bone

more effect seen in femoral neck + distal radius, compared to lumbar spine

Question 20

Calciphylaxis

Answer 20

life-threatening - painful, ischemic cutaneous wounds - tissue calcification (2/2 Ca-P precipitation, which compromises microvasc), dry gangrene, wound sepsis

Question 21

Mgmt calciphylaxis

Answer 21

urgent total parathyroidectomy

Question 22

Familial hypocalciuric hyperCa dx with calcium/Cr ratio of…?

Answer 22

= 0.1

Question 23

Embryology: superior parathyroid arises from…? Inferior parathyroid?

Answer 23

Superior: from 4th pharyngeal pouch
Inferior: from 3rd pharyngeal pouch (along with thymus)

Question 24

Sestamibi scans good for localization of…? But not as sensitive for..?

Answer 24

good for adenomas.

not as sensitive for hyperplasia.

Question 25

If fail to adequately drop PTH levels after resection of one PTH, next step…?

Answer 25

attempt resection of ipsilateral gland first - if still no drop, then explore C/L neck and total parathyroidectomy

Question 26

Embryology: inferior parathyroid glands arise from…?

Answer 26

3rd pharyngeal pouch (w/ thymus)

Question 27

Embryology: superior parathyroid glands arise from…?

Answer 27

4th pharyngeal pouch (w/ lateral thyroid)