Calcium Regulation Flashcards
Hypocalcemia signs
hyperreflexia, twitching, muscle cramps, tingling/numbness
Chvostek sign
facial m. twitches when facial nerve is tapped
Trousseau sign
carpopedal spasm upon inflation of a blood pressure cuff
Hypercalcemia signs
decreased QT interval, conspitation, lack of appetite, polyuria, polydipsia, muscle weakness, hyporeflexia, lethargy, coma
Vit D causes
Ca intake in the intestines by synthesizing calbinin transporter
Ca resorption from the bone
Ca reABsorption from the kidney
Vit D vs PTH in the kidneys
Vit D stimulates Ca AND phosphate reabsorption
PTH stimulates Ca reabsorption but inhibits phosphate reabsorption
Where are the major actions of 1,25-hydroxycholecalciferol?
in the intestines where it stimulates calcium absorption via upregulation of calbindin D28K that can bind four Ca ions
Vit D vs PTH on bone formation
Vit D upregulates RANKL expression
PTH upregulates RANKL and downregulates OPG (osteoprotegrin, inhibitor of RANK-RANKL interactions)
cAMP generated by PTH stimulation
excreted in urine, indicates high PTH stimulation
estradiol-17beta
stimulates calcium absorption from intestine
potent regulator of osteoblast/clast function by promoting osteblast survival and osteoclast destruction
adrenal glucocorticoids
promotes bone resorption and renal expulsion of calcium (calcium wasting)
high levels of cortisol leads to osteoporosis
Primary Hyperparathyroidism
increase in calcium reabsorption, increase in Vit D activation, decease in phosphate reabsorption
Secondayr Hyperparathyroidism
PTH is high because some issue is causing calcium levels to be low in the body
renal failure, vit. d deficiency etc
renal failure causes what parameters on PTH, Ca, P, and VD?
decrease in Ca, increased P, decreased VD, increase in PTH
Vit D deficiency causes what parameters on PTH, Ca, P, and VD?
increased PTH, decreased Ca, decreased P, decreased VD
Primary hyperparathoridism vs secondary
primary is when there is something wrong with the parathyroids like an adeoma, seconday include renal failure an vit D deficiencies
Hypoparathyroidism
causes
thyroid surgery
parathyroid surgery
autoimmune or congenital dysfunctions
Hypoparathyroidism
associated with
most ass. with decreased calcium
muscle spasm, cramping, numbness, etc
seizures, poor teeth, etc
treatment: oral Ca supplement and active form of vitamin D
main parameters of hypoparathyroidism
decrease in Ca, vit D, PTH but INCREASE IN P
Pathophysiology of PTH
albright hereditary osteodystrophy
pseudohypoparathyroidism type 1a
Gs in bone and kidney is defective.
hypocalcemia and hyperphosphatemia
in which disorder is there a decrease in adenylyl cyclase activity
albright hereditary osteodystrophy
pseudohypoparathyroidism type 1a
this is where the Gs protein doesnt activate for activate adenylyl cyclase activity
parameters of pseudohypoparathyroidism
increased PTH
increased P
decreased calcium
decreased Vit D
phenotype of psuedohypoparathyroidism
shortened stature, short neck, obesity, subcutaneous calcification, shortened metatarsals, metacarpals
