Parathyroid Disease Flashcards

1
Q

calcium funciton

A

human skeleton

regulates degree of membrane excitability in nerve cells and muscle cells of GI and heart

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2
Q

nerve cells and hypercalcemia

A

cells are refectory to stimulation

hard to get the nerves excited

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3
Q

nerve cells and hypocalcemia

A

patients develop tetany or carpopedal spasm

nerves are very excitable

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4
Q

calcium levels in blood

A

9.5 mg/dL

half is bound to serum protein, half is ionized and active

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5
Q

calcium homeostasis maintained by

A

kidney, intestines, bones

hydroxylated vitamin D and parathyroid hormone

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6
Q

calcium palace in body

A

sensed by parathyroid and secretion of PTH increases

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7
Q

PTH immediate effects

A

stimulates kidney to hold on to calcium and bones to release calcium quickly bump up serum levels

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8
Q

PTH long term

A

PTH stimulates more absorption of calcium from gut by stimulating kidney to secrete vitamin D which acts at the gut receptor to increase calcium absorption

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9
Q

vitamin D

A

dietary intake or UV rays

biologically inert and must be hydrolyzed in body

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10
Q

vitamin D hydroxylation

A

skin/GI vitamin D

then goes to liver where it becomes 25-hydroxy-vitamin D (calcidiol)

finally goes to kidney where it goes to active 1,25-dihydroxy (calcitrol)

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11
Q

what do we use to measure vitamin D status

A

serum concentration of 25(OH)D

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12
Q

vitamin D toxicity

A

can cause non-specific s/s such as anorexia, weight loss, polyuria, and heart arrythmias

can raise blood levels calcium which leads to vascular and tissue calcification

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13
Q

calcium and the bones

A

bone balance is stimulated by exercise, anabolic, and anti-resorptive drugs

conditions that promote bone formation over bone resorption

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14
Q

effect of PTH (4)

A
  1. stops calcium excretion and promotes urinary phosphate excretion
  2. stimulates kidney to produce vitamin D
  3. activation of ostoeCLASTS
  4. stops activation of osteoBLASTS
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15
Q

normal calcium values

A

9-10.5 mg/dL

ionized levels - 4.5-5.6

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16
Q

severe calcium values

A

> 14 mg/dL

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17
Q

correct Ca

A

serum binding proteins (albumin) can cause falsely elevated levels

(Ca + 4) - albumin

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18
Q

what influences symptoms of high or low Ca

A

severity of derangement (farther from normal)

speed

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19
Q

hypercalcemia s/s

A

shortening of QT interval, HTN and bradycardia

hyperpolaziation of cell membrane

refractory to stimulation

skeletal muscle weakness

easy fatiguability and perceived muscle weakness

constipation, ileus, nausea, vomiting

increased GI acid production -PUD

volume depletion and renal failure

mental status change

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20
Q

workup of hypercalcemia

A
  1. confirm w/repeat lab, check albumin

2. check intact PTH

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21
Q

treatment of asymptomatic hypercalcemia

A

<12 mg/dL

hydration

avoidance of drugs that worsen (thiazides, lithium)

avoidance of factors that worsen it (bedrest, depletion)

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22
Q

treatment of severe hypercalcemia

A

> 14 mg/dL

aggressive IV normal saline to expand volume and IV bisphosphonate (Zometa)

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23
Q

hypocalcemia (nerve)

A

reduces ionic difference across cell membranes therefore making cells hyper excitable

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24
Q

hypocalcemia neuromuscular cell symptoms

A
  1. prolonged QT interval
  2. paresthesias
  3. seizures
  4. muscle spasms/tetany
25
Q

hypocalcemia workup

A

begin with measurement of intact PTH

magnesium, creatinine, phosphate, and vitamin D metabolites

26
Q

hypocalcemia treatment

A

depends on the cause, severity, presence of symptoms and how rapidly hypocalcemia developed

mild tx is asymptomatic, IV replacement is indicated to avoid severe arrhythmia

27
Q

medications used in hypocalcemia

A

calcium gluconate (good!, gradually brings up Ca)

calcium chloride (crap, given in central line)

28
Q

primary hyperparathyroidism

cause

A

mc of hypercalemia in healthy patients

typically results from single autonomous parathyroid adenoma

can be from multi-parathyroid gland hyperplasia

parathyroid cancer (<1%)

29
Q

primary hyperparathyroidism

A

causes mild elevations of serum calcium

relatively asymptomatic

30
Q

diagnosis of primary hyperparathyroidism

A

elevation in serum calcium and elevated intact PTH

31
Q

if symptomatic primary hyperparathyroidism presents with

A

stones (kidney stones)

bones (osteoporosis and bone pain)

groans (constipation/abdominal pain)

moans (psychiatric illness)

32
Q

primary hyperparathyroidism labs

A

serum calcium will be high (>10.5)

ionized serum calcium high (>5.4)

serum iPTH high

serum phosphate LOW

33
Q

primary hyperparathyroidism

treatment

A

asymptomatic: monitored with large fluid intake, pts typically note improvement in anxiety, phobias and mood

significant symptoms- parathyroidectomy

34
Q

following surgery for primary hyperparathyroidism

A

PTH levels rapidly fall and cause hypocalcemia

must measure calcium levels and supplement Ca and Magnesium

hyperthyroidism is common - give propranolol

35
Q

hungry bones

A

following sx for 1 hyperparathyroidism PTH decreases and bone reabsorption falls

rate of bone formation increases so hypocalcemia bc eats up all the calcium

36
Q

hungry bones symptoms

A

parasthesia

spasm

may have seizures

37
Q

secondary hyperparathyroidism

A

found in patients with chronic kidney disease or vitamin D deficiency

kidney fails to normally excrete phosphorus and instead excretes calcium

38
Q

pathophys of secondary hyperparathyroidism

A

hyperphosphatemia and hypocalcemia to stimulate PTH secretion

elevated PTH coinages phosphate loss and mobilizes Ca2+ from bone but kidney can’t do it

failing kidney can’t produce adequate vitamin D so intestinal Ca absorption

parathyroid glands become hyper plastic

renal osteodystrophy w/bone pain (can cause cardiovascular calcification)

39
Q

labs of secondary hyperparathyroidism

A

serum calcium is LOW

ionized calcium LOW

serum PTH is HIGH

serum phosphate is HIGH

40
Q

treatment of secondary hyperparathyroidism

A

reduce dietary intake of phosphates (liquids, diary, protein, other)

patient may be placed on phosphate binders

normalization of vitamin D

41
Q

phosphate binders MOA

A

bind to ingested phosphates, letting them pass out of GI tract without absorption

42
Q

phosphate binders used

A

calcium acetate (PhosLo)

Selevamer (renvela, renegel)

fosrenol (Lanthanum)

43
Q

what medication is used to normalize vitamin D levels

A

calciarlo (rocaltrol)

doxercalciferol (Hectorol)

Paricalcitol (Zemplar)

stimulates to get more calcium from the gut

44
Q

final tool in armamentarium to create secondary HPT caused by CKD

A

cinacalcet (sensipar)

enhances sensitivity of parathryoid calcium receptor

receptor is harder to stimulate

45
Q

tertiary hyperparathyroidism pathophysiology

A

occurs in patients with long-standing CKD after renal transplant

after kidney is transplanted the parathyroid is excessively stimulated and doesn’t recognize serum calcium

autonomously produce excessive parathyroid hormones

46
Q

treatment of tertiary hyperparathyroidism

A

resistant to calcimimetic

can deposit calcium in tissues

treatment is by total or partial parathyroidectomy

47
Q

ddx of all hyperparathyroidism

A

hypercalcemia of malignancy

48
Q

hypercalcemia of malignancy

A

caused by tumor PTrH

low/undetectable intact PTH

49
Q

treatment options for hypercalcemia of malignancy

A

aggressive IV fluid w/saline

bisphosphate (zometa)

50
Q

hypoparathyroidism etiologies

A
  1. iatrogenic
  2. autoimmune destruction
  3. hypomagnesemia

rare, but can be caused by irradiation/infiltrative disease, genetic defect

51
Q

hypomagnesemia is in which population

A

alcoholics

52
Q

s/s of hypoparathyroidism

A

muscular (laryngospasm and bronchospasm)

neurologic

GI

psychiatric

chvostek sign

trousseau sign

53
Q

chovstek sign

A

trapping face causes face to twitch

54
Q

trousseau sign

A

BP causes spasm of hand

55
Q

lab abnormalities of hypoparathyroidism

A

Low PTH
Hypocalcemia
hypomagnesemia
hyperphosphatemia

exclude vitamin D deficiency

56
Q

hypoparathyroidism treatment

A

IV calcium gluconate initially

high oral calcium intake and supplements

vitamin D to maintain

thiazide diuretics (block excretion in urine)

recombinant PTH (BBW - osteosarcoma)

57
Q

pseudohypoparathyroidism

A

tissue insensitivity to PTH (NO underlying disease)

results in hyperphosphatemia and hypocalcemia

elevation in PTH levels to cause bone disease

58
Q

pseudohypoparathyroidism treatment

A

normalizing serum calcium levels, prevent renal excretion of calcium and low PTH