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Flashcards in parathyroid Deck (57):
1

What is the role of PTH

single most important factor in regulation of serum calcium
regulated by level of ionized calcium
major target is kidney and bones

2

what is the action of PTH on the kidneys

increases renal calcium resorption in the tubules
increases phosphate excretion by blocking reabsorption
increases the conversion of Vit D to its active form in the kidneys which increases GI absorption of calcium

3

what is the function of PTH in the rapid phase of calcium homeostasis

PTH binds to receptors on the osteoblast and osteoclasts the membrane pumps Ca from the bone fluid which is transported into blood stream

4

what is the function of PTH in the slow phase of calcium homeostasis

osteoclasts are activated and breakdown formed bone which results in an increase in osteoclastic activity causing calcium to be released into the blood stream increasing Ca levels

5

where is the majority of calcium stored?

99% is in the bone

6

what percent is free

40%

7

what percent is bound to plasma

50%

8

where is vitamin D-3 cholecalciferol former

is formed in the skin with exposure to UV light and Vitamin D-2 is absorbed in our diet

9

Where is Vitamin D-3 activated when it undergoes hydroxylation

in the liver and the the kidney into its active form. Need to be activated in the kidneys in response to PTH stimulation due to low serum calcium levels and low phosphate levels

10

What is the primary action of D-3

is to promote intestinal absorption of calcium and phosphate and enhances bone absorption of Ca

11

As Ca levels increase what happen to PTH secretion, renal vitamin D activation, intestinal Ca absorption and renal phosphate reabsorption?

PTH decreases
Renal Vit-D act decrease
intest Ca abs decreases
Renal phosphate increases

12

where is majority of phosphate located

in bone

13

what does phophate exist as in the blood

phopolipids and phosphate esters and inorganic phosphate(ionized)

14

what is the function of phophate

acts as intra/extracellular anion buffer of the regulation of acid base balance
provides energy for muscle contraction in ATP

15

what is the function of calcitonin

decreased ECF calcium levels
it gets stimulated by large increases in plasma Ca levels

16

What are the targets that calcitonin acts on

bone: inhibits resorption by inhibiting osteoclasts
kidney: stimulates calcium and phosphate excretion in renal tubules

17

what are the 3 hormones that regulate calcium phosphate balance

PHT, Calcitonin and vitamin D
control absorption in intestines
controls deposition and absorption of Ca/P from bone
controls renal reabsorption and excretion of Ca/P by the kidney

18

what is the definition of hyperparathyroidism

abnormal hypersecretion of PTH secretion

19

what are the results of having hyperparathyroidism

hypercacemia hypophosphatemia (hallmark finding)

20

What happens when there is excessive PTH released what are the problems this can have with parts of the body?

wrist and hip fractures due to calcium loss, cystic bone lesions, kidney stones due to hypercalciuria, slowing of the nervous system and musculoskeletal system

21

what is the most common cause of elevated PTH and hypercalcia?

primary hyperparathyroidism

22

who are are the highest risk for hyperparathyroidism

people older than 40
more common in females

23

what is the most common etiology of primary hyperparathyroidism

parathyroid adenoma

24

what are other causes of hyperparathyroidism

parathyroid hyperplasia
parathyroid carcinoma

25

what is secondary hyperparathyroidism

compensatory hyper-functioniong of the parathyroid glands caused by hypocalcemia or peripheral resistance to PTH

26

what is the hallmark of secondary hyperparathyroidism?

elevated PTH, normal to low calcium levels and high renal disease to low vitamin D absorption low phosphate levels

27

what is the most common cause of secondary hyperparathyroidism

chronic renal insufficiency/failure

28

what are other causes of secondary hyperparathyroidism

Vit-D deficienct or abnormal vit D metabolism
calcium malabsorption
medications (phenytoin, phenobarbital, laxitives)

29

what are signs and and symptoms of primary hyperparathyroidism

hypercalcemia is detected by accidental blood work
most pts are asymptomatic of have mild symptoms that might be discovered in ROS

30

what are things you might expect to see with primaryPTH in the kidney/urinary tract?

nephrolithiasis (kidney stones) polyuria, renal colic

31

what are things you might expect to see with primaryPTH in the skeletal system?

bone loss, fractures, bone pain, muscle weakness, myalgias, arthralgias

32

what are things you might expect to see with primaryPTH in the neuromuscular?

muscle weakness, fatigue/malaise

33

what are things you might expect to see with primaryPTH in the neurologic?

depression, nervousness, cognitive dysfunction, physchosis, confusion, headache

34

what are things you might expect to see with primaryPTH in the GI?

peptic disease, pancreatitis, cholelithiasis, N/V, loss of appetite, constipation, abdominal pain

35

what are things you might expect to see with primaryPTH in the Cardio?

HTN, arrhythmias

36

what is the most common presentation of 2nd hyperparathyroidism

renal failure,

37

what are other symptoms of hyperparathyroidism

weaking of bones, fractures, bone pain
heart arrythmias

38

what are the lab values like for primary hyperparathyroidism

Hypercalcemia>10.5mg/dl
Serum phosphate low<2.5mg/dl
elevated PTH

39

what are the lab values like for secondary hyperparathyroidism

serum phosphate is high in kidney failure and low if due to absorption problems
elevated serum PTH
normal serum calcium

40

what is the treatment for primary hyperparathyroidism

1st line is surgery
2nd line is medial therapy

41

When is medical therapy used in patients

pts who are not candidates for surgery
or asymptomatic patients

42

how is a person with hyperparathyroidism managed

fluids to treat hypercalcemia
bisphosphonate IV (lowers serum calcium)
Vit-D supplemetation

43

what are things you want to avoid with primary hyperparathyroidism

Thiazides diuretics, calcium supplements

44

what are things you may want to encourage your patients to do to help with hyperparathyroidism

staying active, hydrated, avoid immobilization

45

how do you treat a person who has secondary hyperparathyroidism

treat underlying condition
Medical therapy is mainstay
Vitamin D supplementation (reduce PTH levels, but may also increase calcium level and contribute to caciphylaxis
phosphate binders
Cacimimetics

46

what are calcimimetics

attach to a receptor on parathyroid cells and increase the ability of the cells to recognize high calcium levels in the bloodstream so less PTH is made
decreases the amount of calcium in the blood

47

what is the next treatment if medical therapy fails

surgical therapy

48

what percent of asymptomatic patients will develop worsening hypercalcemia, hypercalciuria, and reduced bone density

1/3

49

what is hypoparathyroidism

condition where the body does not produce enough PTH and hypocalcemia happens

50

What are some causes of hypoparathyroidism

thyroidectomy
autoimmune
functional due to malabsorption, alcoholism, vitamin D deficiency
congenital
exposure to heavy metals

51

what are acute signs of hypoparathyroidism

tetany
muscle cramps
carpopedal spasm
Irritability
altered mental status
convulsions
stridor
tinglining around mouth, hands, feet
chvosteks sign
trousseaus phenomenon

52

what are chronic signs of hypoparathyroidism

lethargy
personality changes
anxious
blurred vision
parkinsonism
metal retardation
nails thin and brittle
skin dry and scaly
loss of eyebrows

53

what is the trousseaus phenomenon

carpal spasm after application of a BP cuff

54

what are the lab values like for hypoparathyroidism

serum calcium low
serum phosphate is high
PTH level low
Urinary calcium low

55

what are abnormal imaging/special tests for hypoparathyroidism

calcification of basal ganglia
bones may be denser than normal, cutaneous calcification
cataracts
ECG changes- prolonged QTinervals T wave abnormalitie
increased bone mineral density

56

how to treat acute attacks of hypoparathyroidism

maintain open airway
IV calcium gluconcate
oral calcium
Vit-D
magnesium
transplantation of cryopreserved parathyroid tissue

57

What is the long term treatment for hypoparathyroidism

maintain serum calcium between 8-8.6mg/dl
vitamin D supp
PTH injection
avoid calcium depleting drugs(phenothiazine, furosemide)