phys III Flashcards
what is considered hypocalcemia? hyper?
hypo 10.5 mg/dL
Sx hypocalcemia
twitching, muscle cramps, tingling, numbness
Sx hypercalcemia
constipation, polydipsia, polyuria, lethargy, coma, death
majority of phosphate in plasma is in what form
ionized
majority of Ca in plasma is in what form
50% ionized 45% protein bound
what binds Ca
albumin
What does albumin bind in acidemia
more H than Ca so more ionized Ca
what does albumin bind in alkalemia
more Ca than H so less ionized Ca
what hormones regulate Ca
PTH, 1,25-dihydroxyvitamin D
calcitonin
what organs regulate Ca
skeleton, kidney, intestines
what is the Ca sensor R
7 membrane GPCR
senses extracell Ca- ionized Ca
R found on parathyroid cells, parafollicular c-cells and renal tubular cells
what sitmualtes bone resorption? what inhibits it
stimulated by PTH and 1,25 dihydrovit D
inhibited by calcitonin
functions PTH
- Ca and phospate resorption from bone
- promotes Ca resorption from kidney
- promotes phosphate excretion from kidney
- signals 1alpha hydroxylation of 25-hydroxycholecalciferol in kidney
functions of 1,25(OH)2 vit D
bone remodeling promotes mineralization
Ca absorption from gut
renal resorption of Ca and phosphate
negatively feedbacks on its own conversion
What suppresses PTH secretion
high levels extracell Ca
how does PTH increase bone resoprtion
acts on R on osteoblasts which stimulate osteoclasts
severe deficiencies Vit D can cause what
osteomalacia and rickets
what is osteopetrosis and what can cause it
increase in bone density, loss of RANKL
what is Osteoprotegerin OPG
soluble R for RANKL and shuts down resorption by osteoclases
if you lose OPG what results, and why
decrease in bone density, osteoporosis because unregulated RANKL is activation osteoclasts
what is needed to activate the conversion of 25 OH to 1,25 OH in kidney
decrease Ca [ ]
increase PTH
decrease PO4 [ ]
what levels classify severe, moderate, mild and normal Vit D deficiency
normal is >30ng/ml
mild 20-30
moderate 10-20
severe 0-10
if PTH is super super high and blood Ca is low what will you suspect?
kidney failure
if PTH is super high and Ca is normal-high what do you suspect
primary hyperparathyroidism
if PTH is elevated and Ca low what do you suspect
Vit D deficiency
what id PTH is super low, almost 0 and Ca super high
High Ca of malignancy
What are the hyperCa disorders
primary hyperPTH hyperCa of malignancy granulomatous disease Vit D intoxication Vit A intoxication hyperthyroidism thiazide diuretics milk-alkali syndrome immobilization adrenal insufficiency acute renal failure familial hypocalciuric hyperCa
what can cause familial hypocalciuric hypercalcemia
heterozygous inactivation mutation in CaSR
increase PTH and serum Ca
what is key test in Dx hypercalcemia cause
serum PTH
causes of hypoCa
Vit D def hypoPTH pseudohypoPTH hypoMg Renal failure liver failures acute pancreatitis hypoproteinemia
what are key tests in Dx hypocalcemia
25-OH vit D measurement and PTH
if PTH levels are low and patient is hypcalcemic what is Dx
hypoPTH because all other causes hypoCa have high PTH or normal
how do renal and liver disease contribute to hypocalcemia
interfere with Vit D synthesis
how does acute pancreatitis lead to hypo Ca
precipitation of Ca from release of lipid products
what is the key abnormal blood level in pagets disease
increased alkaline phosphatase
have bone pain as cc
