Fiser ABSITE Ch. 23 Parathyroid Flashcards
Where do the superior parathyroid originate? and inferior?
4th pharyngeal pouch, 3rd pharyngeal pouch
Where are the superior parathyroids in relation to the RLNs? and the inferior?
lateral, medial
Where are the superior parathyroids in relation to the inferior thyroid artery? and inferior parathyroids?
above, below
What is the blood supply to the parathyroids?
inferior thyroid artery
What is the most common ectopic site for parathyroids?
tail of the thymus
What is a normal Ca level range?
8.5-10.5
What is a normal PTH level range?
5-40
What is the most common cause of hypoparathyroidism?
previous thyroid surgery
What is the name form bone lesions from Ca resorption; characteristic of hyperparathyroidism?
Osteitis firbrosa cystica (brown tumors)
Indications for parathyroid surgery include symptomatic disease or asymptomatic disease with Ca above what level?
13
What percentage of pts with hyperparathyroid have single adenoma? multiple adenomas? diffuse hyperplasia?
single adenoma 80%
multiple adenomas 4%
diffuse hyperplasia 15%
Hyperparathyroidism in pregnancy carries a risk of still birth. In what trimester do you operate?
2nd
What is the half-life of PTH?
10 minutes
What should be done if parathyroid CA is found?
radical parathyroidectomy and take ipsilateral thyroid
What are the three causes of postop hypocalcemia after parathyroid surgery?
bone hunger, hypomagnesmia, failure of parathyroid remnant or graft
Hypocalcemia postop after parathyroid surgery. What will the levels of PTH and HCO3- be if the cause is bone hunger? and what if it is aparathyroidism?
Bone hunger - normal PTH, decreased HCO3_ Aparathyroidism - decreased PTH, normal HCO3_
What is the study that is used in hyperparathyroidism that is good for picking up adenomas and ectopic glands but not 4-gland hyperplasia?
sestamibi-technetium-99
What is the most common indication for surgery in secondary hyperparathyroidism?
bone pain
What diagnosis should you consider if pt has Ca 9-11, normal PTH (30-60), _ urine Ca?
Familial hypercalcemic hypocalciuria
What is the cause of familial hypercalcemic hypocalciuria?
Caused by defect in PTH receptor in distal convoluted tubule of the kidney that causes _ resorption of Ca
What is the tx for familial hypercalcemic hypocalciuria?
Nothing, no parathyroidectomy because Ca generally not that high
What is the most common location for metastases of parathyroid cancer?
the lung
List the MEN syndromes and components?
MEN I: parathyroid hyperplasia, pancreatic islet cell tumors, pituitary adenomas
MEN IIa: parathyroid hyperplasia, pheochromocytoma, medullary CA of the thyroid
MEN IIb: pheochromocytomas, medullary CA of thyroid, mucosal neuromas, marfan’s habitus
Name the drug used in the management of hypercalcemia that inhibits osteoclasts (used with malignancies or failure of conventional treatment); has hematologic, liver, and renal side effects.
Mithramycin
