Hypocalcemia Flashcards
CNS responsers to hypocalcemia
generally, it’s neuromuscular exciteability because the depolarizaiton threshold lowers in response to low Ca2+.
- perioral numbness
- peripheral paresthesias
- tetany
- seizures
Chvosteks sign
neuro repsonse to hypocalcemia. tap over the zygomatic arch–> see hyperexcitability of cranial nerve #7.
trousseaus sign
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
eye problems in hypocalcemia
cataracts
normal PTH response to hypocalcemia
PTH should be high in an effort to increase Ca2+
someone presents with hypocalcemia. they have a low PTH. first thing on ddx
hypoparathyroidirsm. can be congenital or acquired due to post op neck surgery, or autoimmune causes
most common acquired causes of low PTH (hypoparathyroidism)
post-op neck– surgery or radiation knocked out the parathyroid glands
autoimmune
most common autoimmune cause of hypoparathyroidism
automimmune polyendocrinopahty; multiple autoimmune endocrine disorders
TYPE 1: hypoparathyroid, addisons, mucocutaneous candidiaiss
Type 2; other autoimmune endocrinopahties
person has hypocalcemia. their PTH is high (technically normal). what is the next thing you check?
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.
in PROFOUND vitamin D deficiency, how would PTH, PO4, Urine Ca2+, and bone mass be affected?
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.
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
causes of vitamin D deficiency
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
someone has hypocalcemia. PTH is high. 25-OH-D is normal. what might be a cause?
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.
how does 1,25-diOHvitD, PTH, and PO4 levels change in chronic renal failure
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.
hyperphosphatemia will show ___ levels of PTH and ___ levels of 25vitD
high/normal levels of PTH and normal levels of 25 vid D
treatment of hypocalcemia in the outpatient department, or chronic
- oral calceium with meals
- 1,25 vitamin T. 5000IU vit D3
Why is it important NOT to over treat hypoparathyroidism
if you overtreat with calcium or vitamin D, you cna get hypercalcemia and then kidney stones.
Bones that pagets disease most commonly effects
appendicular skeleton; pelvis, spine, femur, tibia, skull
Investigations and Indications for Therapy of Pagets Disease
