ABSITE Review - Parathyroid Flashcards Preview

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Flashcards in ABSITE Review - Parathyroid Deck (30)
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1
Q

What pouch does the superior and inferior parathyroid originate from?

A

Superior parathyroids - 4th pouch

Inferior parathyroids - 3rd pouch

2
Q

What is the relation of the superior and inferior parathyroid glands to the RLN?

A

Superior parathyroids - Lateral to RLN, above inferior thyroid artery
Inferior parathyroids - Medial to RLN, more anterior, below inferior thyroid artery

3
Q

What is the MC ectopic site for the inferior parathyroid glands?

A

Tail of the thymus

4
Q

What is the MCC of hypoparathyroidism?

A

Previous thyroid surgery

5
Q

What is the oncogen that increases the risk of parathyroid adenomas?

A

PRAD-1

6
Q

How is hyperparathyroidism diagnosed?

A

High Ca, Low Phos, Cl:Phos ratio >33, high renal, high renal cAMP, HCO3- secreted in urine

7
Q

What metabolic disturbance is seen in primary hyperparathyroidism?

A

Hyperchloremic metabolic acidosis

8
Q

What is the name of the bone lesions from Ca resorption?

A

Osteitis fibrosa cystica (brown tumors)

9
Q

What are the indications for surgery in Primary Hyperparathyroidism?

A

Symptomatic disease or asymptomatic disease with Ca >13, low Cr clearance, kidney stones, substantially low bone mass

10
Q

What is the MCC of Primary Hyperparathyroidism?

A

Single adenoma in 80% patients

11
Q

How the intraop PTH works?

A

Can help determine if the causative gland is removed (PTH should go to <50% of the preop value); PTH half life is 10 minutes

12
Q

If you cannot find a parathyroid gland, what is the next step?

A

Check inferiorly in thymus tissue ( MC ectopic location), near carotids, vertebral body, superior to pharynx, thyroid

13
Q

If you can still find the gland, what is the next step?

A

Intraop ultrasound

Close and follow PTH, if PTH still high, get parathyroid scan to localize

14
Q

What is the cause of postop hypocalcemia?

A

Caused by bone hunger, hypoMg, failure of parathyroid remnant or graft

15
Q

What is the utility of the sestamibi-technetium scan-99?

A

Good for picking up adenomas but not 4-gland hyperplasia

Best for trying to pick up ectopic glands

16
Q

In which patients, is secondary hyperparathyroidism usually seen?

A

Renal failure patients

17
Q

What are the laboratory findings of 2ary Hyperparathyroidism?

A

Increase PTH in response to low Ca

18
Q

What is the treatment of 2ary Hyperparathyroidism?

A

Control diet phosphurus, PO4-binding gel, decrease aluminum, Ca supplement, vitamin D, Ca in dialysate

19
Q

What is the MC indication for surgery in 2ary hyperparathyroidism?

A

Bone pain

Others - fractures, or pruritus

20
Q

What is tertiary hyperparathyroidism?

A

Renal disease corrected with transplant but still overproduces PTH

21
Q

What is the surgery of choice for 2ary and 3ary hyperparathyroidism?

A

Subtotal (3.5 glands) or total parathyroidectomy with autotransplantation

22
Q

What lab findings are seen in familial hypercalcemic hypocalciuria

A

Increase serum calcium and low urine calcium

23
Q

What is the cause of familial hypercalcemic hypocalciuria?

A

Caused by defect in PTH receptor in distal convoluted tubule of the kidney that causes increase resorption of calcium

24
Q

In parathyroid cancer, what is the preferred surgery?

A

Wide en bloc excision (parathyroidectomy and ipsilateral thyroidectomy)

25
Q

What is the inheritance of MEN syndrome?

A

Autosomal dominant

26
Q

What are the classic findings of MEN I?

A

Parathyroid hyperplasia - usually 1st symptoms
Pancreatic islet cell tumors - Gastrinoma #1, 50% multiple, 50% malignant
Pituitary adenoma - Prolactinoma #1

27
Q

What are the classic findings of MEN IIa?

A

Parathyroid hyperplasia
Pheochromocytoma - often bilateral, almost always benign
Medullary thyroid carcinoma - often bilateral, #1 cause of death
CORRECT pheochromocytoma first

28
Q

What are the classic findings of MEN IIb?

A

Pheochromocytoma - often bilateral, almost always benign
Medullary thyroid carcinoma - often bilateral, #1 cause of death
Mucosal Neuromas
Marfan’s habitus, MSK abnormalities
CORRECT pheochromocytoma first

29
Q

What is the gene and chromosome of MEN I?

A

MENIN gene in Ch 11

30
Q

What is the gene and chromosome of MEN II?

A

RET proto-oncogene in Ch 10

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