Path: Parathyroid Flashcards
Parathyroid glands are derived from what? along with what other gland
Derived from 3rd and 4th branchial pouches along with thymus
What condition manifests with lack of Parathyroid glands
DiGeorge syndrome
type of cells (2) in the parathyroid glands, their color, and which produces PTH?
chief = PTH = blue oxyphil = pink
5 ways PTH raises calcium
i. Increasing Ca++ reabsorption by the renal tubules
ii. Converting vitamin D to active form in kidney
iii. Increasing Phosphate excretion in kidney
iv. Increasing GI absorption of Ca++
v. Activating osteoblasts –> RANKL –> osteoclasts –> resorb bone
What is the MC cause of clinically apparent hypercalcemia.
Malignancy
Mechanism of hypercalcemia in Sarcoidosis
(upregulated 1-α hydroxylase –> production of active vit D)
adenoma or CA of parathyroids usually leads to hyperPTH?
adenoma
Primary hyperPTH is seen in what 2 familial conditions
MEN1/2 and
familial hypocalciuric hypercalcemia
What is typical age/gender of Primary hyperPTH
> 50, females
What causes familial hypocalciuric hypercalcemia
defective CaSRs (calcium-sensing receptors) means it takes higher Ca levels to suppress PTH –> excesive renal Ca++ uptake–> hypercalcemia/hypocalciuria
What is the MC cause of asymptomatic/incidental hypercalcemia
Primary hyperPTHism
What bone condition is caused by Primary hyperPTHism?
Osteitis Fibrosis Cystica
What is going on in Osteitis Fibrosis Cystica? one hallmark/buzzword
Bone resorption–> hemorrhagic, cystic marrow–> “brown tumors” that consist of osteoclasts and hemosiderin (not malignant)–> bone pain
What 2 things happen to the kidneys in Primary hyperPTHism
Stones and Nephrocalcinosis = interstitial and tubule calcification
What is the mnemonic for CP of Primary hyperPTHism?
“bones, stones, groans, psychiatric overtones”
What is the “groans” component referring to (3)
pancreatitis- Ca activates enzymes
kidney stones
constipation
What change is seen in histo in hyperplasia and adenomas of parathyroid gland
loss of stromal fat
Gross difference between adenoma/CA and hyperplasia
hyperplasia = all 4 glands enlarged adenoma/CA = only one gland enlarged
How is Carcinoma diagnosed?
presence of local invasion/mets. (through capsule)
WHat is MC cause of Secondary HyperPTH
Reanl failure is MC cause
How does renal disease cause Secondary HyperPTH (2)
Phosphate retention –> low serum Ca++
ALso –> low vitaminD dt lack of 1@-hydroxylase activity
What is and what is the cause of Tertiary HyperPTH?
Autonomous hyperPTH dt chronic renal dz (high PTH no matter what Ca levels are doing)
hypoparathyroidism is caused by what gene defect
APS1/AIRE gene
What are the two named signs of hypoparathyroidism
chvostek, trousseau
