Parathyroid Flashcards
Which cells secrete PTH and calcitonin
PTH: chief cells of parathyroid
calcitonin: C-cells of thyroid
Hyperparathyroidism etiologies
adenoma > hyperplasia > carcinoma
Osteitis fibrosa cystica
complication of hyperparathyroidism
resorptin of bone leading to fibrosis and cystic changes
Lab findings in primary hyperparathyroidism
urine cAMP
serum alkaline phosphatase
elevated urine cAMP (Gs cascade)
elevated serum alkaline phosphatase
*because PTH activates blasts, which then activate clasts
Complications of hypercalcemia
metastatic calcifications, esp renal tubules
acute pancreatitis (Ca2+ activates enzymes)
nephrolithiasis
osteitis fibrosa cystica
2˚ hyperparathyroidism
most common etiology
renal failure
decreased phosphate excretion
hyperphosphtemia –> phosphate binds Ca2+, which lowers free serum Ca2+
low free serum Ca2+ => release of PTH
Labs in 2˚ hyperparathyroidism PTH serum Ca2+ serum phosphate alkaline phosphatase
high PTH low serum Ca2+ high serum phosphate high serum alkaline phosphatase *b/c PTH activates blasts first, blasts activate clasts
Hypoparathryoidism
boring etiology
interesting etiology
autoimmune or due to surgical excision
DiGeorge syndrome
-upper pair from 4th pharyngeal pouch
-lower pair from 3rd pharyngeal pouch
Trousseau sign
Chvostek sign
tetany when filling BP cuff
tetany when tapping on facial nerve
First sign of hypocalcemia
perioral numbness
Pseudohypoparathyroism labs
high PTH
low serum calcium
Hypoparathyroidism labs
low PHT
low serum calcium
Pseudohyperparathyroidism
etiology
end organ resistance to PTH
commonly in Gs receptor mutation
short stature and 4th and 5th digits
Inheritance pattern of common form of pseudohyperparathyroidism
dominant
Gs receptor mutation
