parathyroid

Question 1

parathyroid cell types

Answer 1

chief cells

oxyphil cells

Question 2

chief cells

Answer 2

predominate
water-clear appearcne due to cytoplasmic glycogen
secretory granules with PTH

Question 3

oxyphil cells

Answer 3

lots of mito

Question 4

PTH fnx

Answer 4

increases renal tubular Ca absorption
increased activation of Vit D
increased urinary excretion of phosphate
augments GI Ca absorption

Question 5

primary hyperparathyroidism

Answer 5

one of most common endocrine disorders and it is an important cause of hypercalcemia

Question 6

causes of primary hyperparathryoidsim

Answer 6

adenoma (85-95%)
primary hyperplasia
parathyroid carcinoma

Question 7

sporadic mutations in parathyroid adenomas

Answer 7

Cyclin D1 gene inversion

MEN1 mutations

Question 8

familial mutations in parathyroid adenomas

Answer 8

MEN1 and 2
RET
familial hypocalciuric hypercalcemia (rare) -> loss of fnx of CASR

Question 9

parathyroid adenomas

Answer 9

almost always solitary
can be in thyroid or ectopic
usually mostly chief cells

Question 10

primary hyperplasia of parathyrodi

Answer 10

sporadic or in MEN

Question 11

parathyroid carcinomas

Answer 11

may be circumscribed and difficult to distinguish from adenomas or may be obviously invasive
usually enclosed by dense fibrous capsule

Question 12

Dx of parathyroid carcinomas

Answer 12

only way to know is if it invades

Question 13

skeletal abnomralities of hyperparathyroidism

Answer 13

osteoporosis -> dissecting osteitis
brown tumors
osteitis fibrosa cystic

Question 14

osteitis fibrosa cystica

Answer 14

aka con Recklinghausen disease

combo of osteoclast activity, paratrabecular fibrosis, and brown tumors

Question 15

urinary tract in hyperparathyroidism

Answer 15

stones

calcification of renal interstitium and tubules (nephrocalcinosis)

Question 16

asymptomatic hypercalcemia

Answer 16

most commonly caused by primary hyperparathyroidism

Question 17

symptomatic primary hyperparathyroidism

Answer 17

usually malignancy

painful bones, renal stones, abdominal groan, and psychic moans

Question 18

GI issues in primary hyperparathyroidism

Answer 18

constipation, nausea, peptic ulcers, pancreatitis, gallstones

Question 19

CNS and primary hyperparathyroidism

Answer 19

depression, lethargy, seizures, weakness, fatigue

Question 20

secondary hyperparathyroidism

Answer 20

renal failure most common cause

other causes: Ca deficiency, steatorrhea, vit D deficiency

Question 21

chronic renal insufficiency

Answer 21

decreased phosphate excretion -> hyperphosphatemia -> depress serum Ca -> increase PTH
also decrease Vit D activation

Question 22

clinical secondary hyperparathyroidism

Answer 22

usually milder skeletal abnormalities then primary
calciphylaxis
often responds to vit D supplementation

Question 23

calciphylaxis

Answer 23

vascular calcification leading to significant ischemic damage to skin and organs

Question 24

causes of hypoparathyroidism

Answer 24

sugically induces
autoimmune polyendocrine syndrome type 1
autosomal dominant hypoparathyroidism
familial isolated hypoparathyroidism
congenital absence

Question 25

autoimmune polyendocrine syndrome type 1

Answer 25

hypoparathyroidism
chronic candidiasis
primary adrenal insufficiency
mutations in AIRE gene

Question 26

autosomal dominant hypoparathyroidism

Answer 26

gain of fnx in CASR

Question 27

familial isolated hypoparathyroidism (FIH)

Answer 27

rare
autosomal dominant- mutation in PTH precursor
autosomal recessive- mutation in GGM2

Question 28

congenital absence

Answer 28

associated with thymic hyperplasia and CV defects or part of DiGeorge syndrome

Question 29

symptoms of hypocalcemia

Answer 29

tetany
paresthesia
capopodal spasm
seizures
mental status changes
calcification of basal ganglia -> parkinsonian like disorders
long OT

Question 30

signs of hypocalcemia

Answer 30

Chvostek (facial mm contractions on mechanical stimulation)

Trousseau (carpal spasms if blood flow occluded by bp cuff)

Question 31

pseudohypoparathyroidism

Answer 31

end-organ resistance to actions of PTH
serum PTH levels are normal or elevated
sometimes can have resistance to THS, FSH, and LH
all are GPCRs