Hypocalcemia

Question 1

CNS responsers to hypocalcemia

Answer 1

generally, it’s neuromuscular exciteability because the depolarizaiton threshold lowers in response to low Ca2+.

• perioral numbness
• peripheral paresthesias
• tetany
• seizures

Question 2

Chvosteks sign

Answer 2

neuro repsonse to hypocalcemia. tap over the zygomatic arch–> see hyperexcitability of cranial nerve #7.

Question 3

trousseaus sign

Answer 3

neuro test for CNS response to hypocalcemia. tetany test where you occlude a radial pulse.

• lowers depolarization threshold which is already low because of hypocal.
• then causes involuntary muscle contraction

Question 4

eye problems in hypocalcemia

Answer 4

cataracts

Question 5

normal PTH response to hypocalcemia

Answer 5

PTH should be high in an effort to increase Ca2+

Question 6

someone presents with hypocalcemia. they have a low PTH. first thing on ddx

Answer 6

hypoparathyroidirsm. can be congenital or acquired due to post op neck surgery, or autoimmune causes

Question 7

most common acquired causes of low PTH (hypoparathyroidism)

Answer 7

post-op neck– surgery or radiation knocked out the parathyroid glands

autoimmune

Question 8

most common autoimmune cause of hypoparathyroidism

Answer 8

automimmune polyendocrinopahty; multiple autoimmune endocrine disorders

TYPE 1: hypoparathyroid, addisons, mucocutaneous candidiaiss

Type 2; other autoimmune endocrinopahties

Question 9

person has hypocalcemia. their PTH is high (technically normal). what is the next thing you check?

Answer 9

25-OH Vit D. Inactive vitamin D.

• can be low or not low.
• if its VERRRRRRRY Low it could be cause hypocalcemia. It would be due to malabsorpton, liver disease, or anti-convulsants that cause vitamine D degradation.

Question 10

in PROFOUND vitamin D deficiency, how would PTH, PO4, Urine Ca2+, and bone mass be affected?

Answer 10

PTH: high; trying to keep ca2+ normal despite low vitamin D

PO4: LOW; because PTH is high, PO4 is reduced

Urine calcium; low, you are resorbing the calcium since you have low vit d and are hypocalcemic

bone mass; low; trying to make up for low serum calcium, your bone will start to break down.

Question 11

NOTE: Hypocalcemia can only result from PROFOUND VITAMIN D DEFICIENCY. if someone only has moderate or even significant vitamin D defieicney, they will not present with frank hypocalcemia

Question 12

causes of vitamin D deficiency

Answer 12

colored skin; darker skin needs 5-10x sun exposure to generate same vit D as white

• aging diminishes 7-DHC in skin
• place of residence; not vitamin D generationi from sun exposure between October and March

Question 13

someone has hypocalcemia. PTH is high. 25-OH-D is normal. what might be a cause?

Answer 13

chronic renal failure. if you don’t have properly functionining kidneys, you can’t produce 1-alpha-hydroxylase. which means you can activate vitamin D. therefore you have low vitamin D, resulting in hypocalcemia,

also hyperphosphatemia.

Question 14

how does 1,25-diOHvitD, PTH, and PO4 levels change in chronic renal failure

Answer 14

1,25vitD: low, loss of 1lAlhydroxylase prevents activation of vit D

PTH: high; because of decrease vi D and subsequent low Ca2+

PO4: high because kidney can’t excrete phosphate adequatly. should be LOW if kidney was intact and PTH was high.

Question 15

hyperphosphatemia will show ___ levels of PTH and ___ levels of 25vitD

Answer 15

high/normal levels of PTH and normal levels of 25 vid D

Question 16

causes of hyperphosphatemia

Answer 16

1. precipitates with calceium
2. tumor lysis
3. rhabdomyolysis
4. oral phosphates abuse (laxatives)

Question 17

treatment of hypocalcemia (ACUTE and SEVERE)

Answer 17

1. IV access, ABCs
2. IV calcium gluconate
3. 2-3 amps over 20 min
4. start oral treatment if expected to be needed
   - may need IV calcium infusion in some cases.

Question 18

treatment of hypocalcemia in the outpatient department, or chronic

Answer 18

• oral calceium with meals
• 1,25 vitamin T. 5000IU vit D3

Question 19

Why is it important NOT to over treat hypoparathyroidism

Answer 19

if you overtreat with calcium or vitamin D, you cna get hypercalcemia and then kidney stones.

Question 20

Question 21

outline the pathology of Pagets disease

Answer 21

uncontrolled formation and activity of large osteoclasts. Results in excessive bony resorption. Chaotic osteoblastic activity follows, resulting in disorganized bone histology, fibrosis, and increased vascularity.

Question 22

Bones that pagets disease most commonly effects

Answer 22

appendicular skeleton; pelvis, spine, femur, tibia, skull

Question 23

symptoms of pagets disease

Answer 23

• it’s rarely diagnosed before 50.
• bone pain at involves sides. night vs OA, full.
• adjacent joint arthritis.
• bony deformity
• pathological fractures
• mononeuropathies (deformity/compression of neural foramina)

Question 24

Investigations and Indications for Therapy of Pagets Disease

Answer 24