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Flashcards in Calcium and Parathyroid Deck (30):
1

When Ca receptors on PTgland sense low calcium, what happens

increase in parathyroid hormone release --> will increase renal calcium absorption and increased bone resorption/release of calcium, increase formation of active form of VitD

2

Vitamin D hydroxylation

2 hydroxylations: 1st in liver, 2nd in kidney (second hydroxylation stimulated by PTH)

3

Calcitriol/Vitamin D

increases calcium absorption in gut --> increase serum calcium

4

Hyperparathyroidism

"bones, groans, stones, and psychic moans" --> abnormal PTH hypersecretion --> hypercalcemia

5

Most primary hyperthyroidism is caused by

solitary (single PT) adenoma (85%), diffuse hyperplasia (15%), parathyroid carcinoma <1%

6

T/F in pt adenoma, may have hypertrophy of other pt glands

F --> atrophy b/c of negative feedback from high calcium due to hyperactive pt

7

hypercalcemia can lead to increase/decrease in ECF phosphate

decrease --> increased urinary phosphate is an effect of pth and overrides the phosphate released from bone with calcium

8

Groans

increased PTH can increase bp, constipation, GI tone

9

Classical presentation of primary hyperparthyroidism

osteitis fibrosa cystica --> bone demineralization with subperiosteal bone resorption and bone cysts

10

Realistic presentation of primary hyperparathyroidism

elevated serum calcium, kidney stones, renal dysfunction, reduced bone mineral density (cortical bone)

11

Tx of hyperparathyroidism

asymptomatic: medical monitoring // surgery for kidney stones, fracture in symptomatic patients or asymptomatic patients<50 years with severe hypercalcemia or reduced creatinine clearance or low bone mass

12

Secondary hyperparathyroidism

hyperfunctioning Pt glands are compensating for hypocalcemia: renal insufficiency, calcium malabsorption, vitamin D deficiency

13

Tertiary hyperparathyroidism

gland hyperfunction and hypersecretion due to prolonged secondary hyperparathyroidism --> gland autonomy --> elevated calcium, requires surgery

14

Familial hypocalciuric hypercalcemia

autosomal dominant --> looks like primary hyperparathyroidism --> abnormal calcium sensor --> increase in calcium setpoint --> increased pth secretion --> elevated calcium --> low urine calcium

15

Difference between FHH and Primary hyperparathyroidism

low urine calcium in FHH --> calcium sensor in kidney also broken --> cannot flush out calcium

16

Hypoparathyroidism

following total thyroidectomy or radical neck dissection, infiltrative (hemochromatosis or wilson's), congenital (digeorge, familial type 1 polyendocrine)

17

Hypocalcemia effects

cardiac arrhythmia, neuromuscular irritability/tetany

18

Chvostek sign

irritable facial nerve due to hypocalcemia

19

Trousessau's sign

carpal spasm due to hypocalcemia

20

Trousseau or Chvostek is more specific

Trousseau --> but takes a whole 3 minutes in the clinic

21

Tx of hypoparathyroidism

oral calcium, vitamin D,monitoring urinary/serum calcium,

22

Goal is serum calcium level in patient with hypoparahtyroidism

low normal --> will lose a lot of calcium in the urine b/c of absence of pth --> want to avoid kidney stones so go low normal

23

Vitamin D intoxication

uncommon cause of hypercalcemia --> nausea, vomiting, weakness, AMS

24

sequelae of Vitamin D intoxication

stored in fat --> cannot chelate it --> prolonged hypercalcemia

25

Tx of D intoxication

hydration, no dietary calcium

26

Vitamin D deficiency

lack of sun, decreased intake/absorption of vitamin D, metabolic defects in vitamin D hormone system --> leads to secondary hyperparathyroidism

27

Sequelae of vitamin d deficiency

rickets in children, osteomalacia in adults --> widened osteoid (demineralized bone) seams and impaired mineralization, risk of osteoporosis

28

_______ is important in mineralization of devoid bone matrix to lay down calcium.

Vitamin D

29

Characteristic signs of osteomalaci

diffuse bone pain and tenderness, proximal muscle weakness, Looser-Milkman pseudofractures perpendicular to bone surface

30

Tx of Vitamin D deficiency

treat underlying disorder, calcium, vitamin D