B6.050 Post CBCL Formative Info Flashcards
what are reasons you might expect a rare parathyroid carcinoma?
palpable neck mass
hypercalcemia > 14 mg/dL
parathyroid adenoma and hyperplasia do not present as palpable masses
histology of a parathyroid malignancy
marked mitotic activity, dense fibrous stroma, evidence of local invasion into capsule or surrounding vessels
metastasis most common to lymph nodes
histology of parathyroid hyperplasia
diffuse proliferation of clear cells with little remaining normal tissue
histology of parathyroid adenoma
single focus of chief cells, surrounded by a compressed rim of normal tissues
first sign of MEN 1
parathyroid adenomas and 4 gland hyperplasia
presents with increased PTH and Ca
typically in 3rd or 4th decade w no gender predilection
symptoms of hypercalcemia in MEN 1 patients
involve urinary tract rather than the skeleton
many are asymptomatic
treatment of MEN 1 parathyroid disease
- 5 gland (subtotal) resection
goal: achieve normocalcemia for as long as possible while avoiding hypoparathyroidism
other tumors associated with MEN 1
pancreatic endocrine tumors
pituitary tumors
thymic carcinoids
pancreatic tumors in MEN 1
gastrinoma (Zollinger Ellison, PUD and diarrhea)
insulinomas
VIPomas
glucagonomas
pituitary tumors in MEN 1
prolactin
GH
mutation in MEN 1
MENIN tumor suppressor on chromosome 11
significance of lithium induced HPTH
more likely to need a 4 gland exploration since all 4 glands are exposed to the effects of lithium
higher tendency to cause 4 gland hyperplasia than in the normal population
3 Ps of MEN 1
parathyroid
pancreas
pitutitary
describe pseudohypoparathyroidism
target tissue resistance to PTH
low serum calcium
elevated serum PO4
defect in skeletal growth and development
disorder associated with pseudohypoparathyroidism
mutations in GNAS1
PTH function is normal, but kidney cannot respond to PTH stimulation due to loss of functional signaling pathway
additional surgery in MEN 1 parathyroid disease
bilateral thymectomy
patients have a greater incidence of thymic carcinoids as well as ectopic parathyroid glands
when you resect a parathyroid gland that you thought was the cause of HPTH, and the PTH doesn’t go down, what do you do?
check ipsilateral gland next
if adenomatous, resect this one too
if PTH still doesn’t drop, move to contralateral side and do a total parathyroidectomy
auto implantation follows
EKG finding with hypocalcemia
prolonged QT interval
T wave inversion
treatment for severe hypocalcemia
IV 10% calcium gluconate to achieve serum conc of 7-9 mg/dL
also correct associated deficits in Mg, K, and pH
how does severe hypomagnesemia perpetuate hypocalcemia
low Mg can suppress PTH release
low Mg can stimulate osteoblastic activity
how does modest hypomagnesemia perpetuate hypocalcemia
impair end organ response to PTH
earliest clinical feature of hypocalcemia
numbness
tingling in circumoral region or tips of fingers
profound clinical features of hypocalcemia
tetany
seizure
Trousseau sign
Chvostek’s sign
where is calcitonin produced
perifollicular C cells of thyroid
