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Flashcards in PTH Deck (37):
1

Why does primary hyperthyroidism occur?

Autonomous PTH secretion secondary to glandular hyperplasia
Parathryroid adenomas
Parathyroid carcinoma (rare)

2

What are the clinical manifestation of hyperparathyroidism caused by?

Hypercalcemia

3

T/F removal of hyperfunctioning parathyroid gland is usually curative for hyperparathyroidism

True, 90% cure rate

4

Where do the parathyroid glands originate from embryonically?

Upper glands- from 4th brachial pouch
Lower glands (and thymus)- from 3rd brachial pouch

5

Where are the parathyroid glands located?

Upper glands are behind thyroid, close to the inf thyroid artery
Lower glands w/in 2 cm of lower thyroid pole

6

What is the arterial supply to the parathyroid glands

All 4 are supplied by the inferior thyroid artery.

7

Where are aberrant glands usually located?

Upper abberant- intrathyroid or posterior mediastinal
Lower abberant- intrathymic or anterior mediastinal

8

What are the effects of primary hyperthyroidism on calcium and phosphate?

Excess PTH means calcium is taken out of bones, and there is also stimulation of renal tubular absorption of calcium. So, there is hypercalcemia.
Excess PTH inhibits renal phosphate reabsorption, so it's peed out and there is hypophosphatemia.
Overall, total body calcium and phosphate wasting occur --> osteoporosis and bony mineral loss.

9

What associated conditions can develop as a result of hyperparathyroidism's metabolic imbalances?

pancreatits
nephrolithiasis
nephrocalcinosis
gout
pseudogout
HTN
peptic ulcer dz

10

What is secondary hyperparathyroidism?

Usu in pts w renal dz.
Hyperphosphatemia causes Hypocalcemia, which stim's PTH production.
The PTH glands are usu hyperplastic since there is chronic hypocalcemia.
(Note that this is the OPPOSITE of the Ca and Phosphate levels in primary hyperparathyroidism!)

11

What is tertiary hyperthyroidism?

Usu in dialysis-dep pts w ESRD
Caused by long-standing secondary hyperparathyroidism- persistent hypocalcemia causes devt of autonomous hyperplastic gland fn. Since gland is autonomous, it can produce as much PTH as it wants.

12

What is Pseudohyperparathyroidism?

Like primary- hypercalcemia, hypophosphatemia
But dt oat cell cancer or squamous cell cancer of the lung, head/neck, kidney, or ovary.
These cancers make PTHrP, which causes hypercalcemia.

13

T/F the majority of cases of hyperparathyroidism are dt a single hyperfunctioning adenoma

True.
Most cases are sporadic.

14

What are the genetic origins of hyperparathyroidism?

MEN I or IIa

15

What is MEN I?

Wermer's 3 p's:
parathyroid
pituitary
pancreas

16

What is MEN IIa?

Sipple:
hyperparathyroidism
pheochromocytoma
MTC

17

T/F Pts with MEN I or II require removal of all 4 parathyroid glands.

True.
Usu have diffuse 4-gland hyperplasia, so require bilateral neck exploration for removal of all glands.

18

Risk factors for developing hyperparathyroidsim

Childhood radiation therapy to head/neck
Fam hx of MEN

19

T/F pts w hyperparathyroidism are generally asx at px

True- dx is usu made after discovering hypercalcemia on routine screening.
In the past, pts px'd w ESRD d/t staghorn caliculi and obstructive uropathy; also with pathologic fractuers.

20

Sx of hyperparathyroidism

Bones
Stones
Abd groans
Psychic moans
Fatigue overtones

21

Bone sx in hyperparathyroidism

aches, arthralgias from structural chgs in bony architecture (dt hypercalcemia, no calcium in bones)
Pseudogout (chondrocalcinosis) causes severe joint pain when articular cartilage becomes calcified.

22

"Stones" sx in hyperparathyroidism

Renal caliculi from hypercalcemia can cause renal colic sx
Calculi can also cause obstructive uropathy --> UTIs, renal failure
can also have nephrocalcinosis- calcification of renal parenchyma

23

"Abd groans" sx in hyperparathyroidism

Filtration of high serum calcium loads --> dehydration, constipation
Pancreatitis
Can stimulate gastin production --> elevated gastric acid secretion
Peptic ulcer dz

24

"Psychic moans" and "fatigue overtones" in hyperparathyroidism

Hypercalc --> anorexia, naus/vom.
High mineral lvls in kidney --> polyuria --> thirst, polydipsia
Behavioral chg- mood swings, organic psychosis, dementia
Lassitude, muscular fatigue

25

Phys Ex for hyperparathyroidism

Usu nothing.
Occasional palpable neck mass
Rarely, focal bone swelling- dt brown tumors of osteoclasts

26

Most common cause of hypercalcemia?

Mets to bone. (osseous metastatic dz)

27

Dx eval for hyperparathyroidism

Persistent hypercalcemia
Elevated serum PTH
Elevated alk phos if bony dz
Elevated creatinine if renal dz
XR- subperosteal reabs of phalanges, osteopenia, osteoclastomas, mets calcifications
Bone density scan for osteopenia
Abd XR for renal calculi or nephrocalcinosis

28

Rx for hyperthyroidism

Remove hyperfng glands.
Pre-op localization of tumor w sestamibi scan
also intra-op rapid PTH immunoassay

29

What are the sx of hypercalcemic crisis? what is the rx?

Coma
delerium
anorexia
vom
abd pain
Rx: IV hydration and forced calciuresis w furosemide. After stabilized, surgery.

30

T/F once the tumor is removed, PTH levels should decrease siginificantly

True,
should decrease to <25% of baseline.

31

Operation for primary hyperthyroidism

Curvilinear necklace incision
Most tumors are attached to posterior capsule of thyroid, on top of recurrent laryngeal n. and next to inf thyroid artery.
Remove only the problematic gland, but find all 4 in case of multiple adenomas.

32

Operation for parathyroid hyperplasia

All glands are diseased, so remove all except one.
Subtotal excision of one gland prevents hypocalcemia.

33

Rx for secondary and tertiary hyperparathyroidism

secondary- it's dt renal dz and low Ca2+, so treat medically
tertiary- it's dt autonomous gland hyperplasia, so it sometimes requires surgery.

34

What happens after parathyroid surgery?

Hypocalcemia (secondary to reduced PTH lvls)
Osseous remineralization (hungry bones)

35

Sx of hypocalcema

periorbital numbness
parasthesia
carpopedal spasm
seizures
Chovstek's sign of hypocalcemia- tap facial nerve in cheek and cause muscle spasm

36

Rx for hypocalcemia

Mild- give oral Ca2+ supplements and high calcium diet
If spasm/seizure- immed IV calcium gluconate or calcium chloride

37

T/F Recurrent hyperparathyroidism after gland removal is possible.

True, happens in 5% of single adenoma removal
do re-exploration w sestamibi and PTH assay.