parathyroid

Question 1

how many parathyroid glands are there?

Answer 1

4

Question 2

what do the parathyroid glands produce

Answer 2

parathyroid hormone (aka parathormone)

Question 3

why is PTH released into the blood

Answer 3

dependent on plasma calcium concentration - released by negative feedback mechanism

• hypocalcemia = release
• hypercalcemia = suppress both synthesis and release

Question 4

what is half life of PTH?w

Answer 4

4 minutes

Question 5

what is the average PTH level?

Answer 5

8-51 pg/mL

Question 6

what is the goal of the thyroid gland/PTH

Answer 6

to maintain normal plasma calcium levels

Question 7

calcium moves across what 3 interfaces?

Answer 7

GI tract, renal tubule, bone

Question 8

resorption definition

Answer 8

absorption into circulation

Question 9

what do osteoclasts do?

Answer 9

they break down the bone tissue and release minerals, resulting in the transfer of calcium from bone tissue to blood

they are found on the surface of bones and are multi-nucleated cells that contain mitochondria and lysosomes that break down bone tissue by digestion and degradation

Question 10

what does PTH do to the kidneys?

Answer 10

stimulates calcium reabsorption, and depresses PO4 reabsorption

Question 11

what does PTH do to the guts

Answer 11

increased calcium and phosphorous reabsorption

Question 12

what does calcitonin do?

Answer 12

it opposes the effects of PTH and lowers blood calcium in 3 ways

1. inhibits osteoclast activity in bones (promotes bone storage of calcium)
2. inhibits renal tubular reabsorption of calcium
3. inhibits calcium reabsorption in intestines

Question 13

where is calcitonin secreted

Answer 13

by parafollicular cells in thyroid

Question 14

what stimulates calcium secretion

Answer 14

hypercalcemia

Question 15

what does vitamin D do?

Answer 15

it increases intestinal absorption of calcium, magnesium, and phosphate

Vitamin D receptors:
helps transport proteins that absorb calcium in intestine
bone resorption
reabsorption of calcium in in distal nephron

Question 16

how do you get vit D2 (cholecalciferol) and Vitamin D3 (ergocalciferol)

Answer 16

you get them through diet
synthesis of D2 is dependent on sun exposure
D2 and D3 get hydrolyzed in liver to 25-hydroxyvitamin and then again in kidney to form 1,25 hydroxyvitamin D

Question 17

what are the normal calcium levels

Answer 17

total - 9.5-10.5

iCal - 4.75-5.7

Question 18

percentage breakdown of how calcium is hanging out in your body

Answer 18

50% serum bound to albumin
40% ionized and active
10% bound to chelating agents (phosphate, citrate, sulfate)

Question 19

what does acidosis do to serum calcium

Answer 19

increases

Question 20

what does alkalosis do to serum calcium

Answer 20

decreases

Question 21

each 0.1 decrease in pH increases ical by?

Answer 21

0.05

Question 22

of the calcium in your body, what percentage is in your bone?

Answer 22

99% - helps with bone formation, reservoir for calcium

Question 23

what does calcium do in the ECF?

Answer 23

blood clotting

excitability of nerve and muscle

Question 24

what doe calcium do intracellularly?

Answer 24

metabolic regulation for action of hormones and enzyme activation

Question 25

hyperparathyroidism - what is it?

Answer 25

excess production of PTH

Question 26

what is the most common cause of hypercalcemia

Answer 26

hyperparathyroidism

Question 27

what is hypercalcemia defined as

Answer 27

20.4

Question 28

what causes primary hyperparathyroidism

Answer 28

parathyroid destruction excessive secretion of PTH d/t benign adenoma (80-90%), hyperplasia (15%), carcinoma (<1%)

Question 29

what causes secondary hyperparathyroidism

Answer 29

appropriate response to hypocalcemia as seen in CKD

Question 30

50% of patients with hyperparathyroidism are?

Answer 30

ASYMPTOMATIC

Question 31

what are the manifestations of hypercalcemia

Answer 31

primary kidneys and skeletal system - calcium deposits in renal parenchyma, recurrent nephrolithiasis, skeletal pathology

Question 32

at what calcium level would you expect symptoms most commonly

Answer 32

above 11.5-12

Question 33

how do you diagnose hyperparathyroidism?

Answer 33

PTH assay, calcium level, vit D level, renal function, CT scan, has anything happened to neck? albumin?

Question 34

medical management of hyperparathyroidism

Answer 34

for mild/asymptomatic - mild hypercalcemia (12) = hydration - moderate to sever hypercalcemia (13-15) - IV saline hydration and furosemide to promote Na/Ca diuresis

Question 35

surgical management of hyperparathyroidism

Answer 35

definitive treatment intraoperative PTH assay is measure before and at 5 minute intervals after adenoma removal to confirm a rapid fall to normal

Question 36

if you have multiple-gland hyperplasia, what do you do?

Answer 36

all glands must be identified and either 1. remove 3 with partial excision of fourth, leaving good blood supply or 2. total parathyroidectomy with immediate transplantation of removed, minced parathyroid gland into forearm muscle

Question 37

hypoparathyroidism - what is it

Answer 37

absence or deficiency in PTH or resistance of peripheral tissue to the effects of the hormone, can be iatrogenic or removed surgically with thyroidectomy (on accident) ***results in hypocalcemia

Question 38

what are the signs of hypocalcemia?

Answer 38

``` neuronal irritability skeletal muscle spasm tetany seizure fatigue and mental status change prolonged QT congestive heart failure - chronic acute hypotension ```

Question 39

what can acute hypocalcemia cause??

Answer 39

stridor, laryngospasm, apnea, and hypotension

Question 40

how do you treat hypocalcemia

Answer 40

give electrolyte replacement calcium and vitamin D manage hypomagnesemia

Question 41

how is hypomagnesemia managed?

Answer 41

oral or IV replacement - calcium and mag functionally compete for transport in the thick ascending limb of look of Henle

Question 42

severe symptomatic hypocalcemia

Answer 42

requires 10-20 mL of 10% calcium gluconate or 3-5 mL of 10% calcium chloride followed by a continuous infusion of calcium 1-2mg/kg/h

Question 43

what are the major anesthetic risks of hypocalcemia

Answer 43

decreased cardiac contractility and dysrhythmias tetany altered response to muscle relaxant risk for laryngospasm

Question 44

if you don't treat an overactive parathyroid gland, what problems will arise

Answer 44

fatigue, bad memory, kidney stones, osteoporosis

Question 45

what is the incidence of developing a parathyroid tumor

Answer 45

1 in 100 | and 1 in 50 women over 50

Question 46

anesthetic management of parathyroidectomy

Answer 46

elevated calcium can lead to cardiac dysrhythmias use a NIMs ETT to assess RLN NMBDs are unpredictable - use qualitative monitors careful positioning - risk for fracture ``` supine, arms tucked, gel head ring ether screen and 2 clicks down on bed for neck extension 2 PIVs antiemetic coverage GA with NIMs monitoring inhalation agent remifentanil no abx ```

Question 47

what does hypercalcemia do to the heart rhythm

Answer 47

decreases refractory period and increase ventricular excitability

Question 48

what are the postop complications of parathyroid surgery

Answer 48

RLN injury, hematoma, hypocalcemia (acute only if severe deficit preop or injury to all glands)

Question 49

if you are doing parathyroid only

Answer 49

large IV for PTH sampling position NIBP cuff to function as torniquet with a stopcock inserted between 6in connector tubing and IV tubing you could a-line consider saphenous IV

Question 50

for parathyroid surgery when should you get PTH samples

Answer 50

baseline at time of removal and then every 5 minutes after that for 15 minutes