Parathyroid pathoma 01-20 Flashcards
What secrete chief cells?
secrete PTh -> regulate calcium in serum
PTH on osteoclasts?
increase osteoclast activity -> incr. serum Calcium and PO4
PTH on small bowel?
increase Ca and PO4 reabsorbtion (INDIRECTLY BY ACTIVATING vit D).
PTH on renal?
Incr. Ca reabsobtion in distal tubule
and decr. reabsorbtion PO4 in proximal tubule
PTH. where in kidney calcium?
Incr. Ca reabsobtion in distal tubule
PTH. Decr PO4 in kidney where?
decr. PO4 reabsorbtion in proximal tubule
PTH regulation?
increased serum Ca negative feedback to decrease PTH secretion
Primary hyperparathyroidism. Mechanism?
Excess of PTH due to primary disorder of the PARATHYROID GLAND
Primary hyperparathyroidism. most common cause?
parathyroid adenoma - benign neoplasm, usually involve one gland
sporadic hyperplasia and carcinoma is less common
Primary hyperparathyroidism. symptoms in general?
asymptomatic hypercalcemia
Primary hyperparathyroidism. kidney?2
nephrolithiasis calcium oxalate);
Nephrocalcinosis - metastatic calcification of renal tubules -> renal insuf., and polyuria
Primary hyperparathyroidism. cns?
CNS disturbances - depression, seizures
Primary hyperparathyroidism. gut?
constipation, peptic ulcer disease, acute pancreatitis
Primary hyperparathyroidism. bones?
osteitis fibrosa cystica - reabsorbtion of bone leading to fibrosis and cystic spaces
Primary hyperparathyroidism. lab? PTH, Ca, PO4, urinary cAMP, ALP?
incr. PTH, incr. Ca, decr. PO4, incr. urinary cAMP, incr. ALP (due to osteo
Primary hyperparathyroidism. treatment?
surgical removal of the affected gland
Secondary hyperparathyroidism. mechanism?
excess production of PTH due to a disease process EXTRINSIC to the parathyroid gland
Secondary hyperparathyroidism. most common cause?
chronic renal failure
Secondary hyperparathyroidism. Chronic renal failure. PO4, Ca, PTH, ALP?
renal insuf leads to incr. PO4 -> binds Ca -> decr. Ca
Decr. Ca promotes PTH secretion -> bone reabsorbtion -> renal osteodystrophy
lab. Incr. PO4, decr. Ca, incr PTH, incr ALP
Hypoparathyroidism. PTH?
low PTH
Hypoparathyroidism. causes?
autoimmune damage to parathyroids, surgical excission, DiGeorge syndrome
Hypoparathyroidism. general symptoms?
related to low serum calcium
Hypoparathyroidism. hypocalcemia symtoms?2
numbness and tingling (particulary circumoral)
muscle spasm (tetany) - may be elicited with filling of a blood pressure cuff - oclussion of brachial artery (trouseou sign) or tapping on the facial nerve (chvostek sign)
Hypoparathyroidism. lab?
low PTH, low Ca, hyperphosphatemia
pseudohypoparathyroidism 1A. mechanism?
AD. Inactive Gs protein alfa subunit cause end organ (kidney and gut) resistance to PTH.
pseudohypoparathyroidism 1A. kidney mechanism?
unresponsiveness of kifney to PTH -> hypocalcemia despite incr. PTH.
pseudohypoparathyroidism 1A. symptoms?
presents as Albright hereditary osteodystrophy: shortened 4th/5th digits, short stature, obesity, development delay.
MUST BE INHERITED FROM MOTHER due to imprinting
Pseudopseudohypoparathyroidisim. inheritance?
AD
Pseudopseudohypoparathyroidisim. mechanism?
Physical appearance of Albright hereditary osteodystrophy but WITHOUT END ORGAN RESISTANCE TO PTH.
Pseudopseudohypoparathyroidisim. pth and calcium?
normal PTH and normal.
Pseudopseudohypoparathyroidisim. mechanim?
Defective Gs protein alfa subunit inherited from father.
Pseudopseudohypoparathyroidisim. why normal responsivnes to PTH?
Normal allele maintains responsivness of kidney to PTH
