Parathyroid: Guerin

Question 1

parathyroid histology: chief cells

Answer 1

central, round, uniform nuclei
light pink cytoplasm, can be clear from glycogen
secretory granules of PTH

Question 2

parathyroid histology: oxyphil cells

Answer 2

slightly larger than chief cells
acidophilic cytoplasm
tightly packed with mitochondria

Question 3

causes of hypercalcemia with decreased PTH

Answer 3

1) hypercalcemia of malignancy
2) vitamin D tox
3) immobilization

thiazide diuretics

granulomatous disease (sarcoidosis)

Question 4

causes of hypercalcemia with raised PTH

Answer 4

hyperparathyroidism

1) primary (adenoma > hyperplasia)
2) secondary, compensatory hypersecretion PTH due to prolonged hypocalcemia, chronic renal failure
3) tertiary, hyper PTH even after prolonged hypocalcemia corrected like after renal transplant

familial hypocalciuric hypercalcemia

Question 5

two molecular defects play a role in sporadic parathyroid adenoma

Answer 5

cyclin D1 gene inversions

MEN1 mutations

Question 6

familial syndromes with parathyroid adenoma

Answer 6

MEN type 1 and 2: MEN 1 and RET mutation

familial hypocalciuric hypercalcemia

• rare AD disorder
• mutation in CASR

Question 7

morphology of adenoma

Answer 7

*****solitary
0.5-5gm
well circumscribed
glands outside adenoma usually normal in size or shrunken
hypercellular with little to no fat
uniform chief cells
few nests of larger oxyphil cells
rim of compressed parathyroid gland, generally separated by fibrous capsule

Question 8

parathyroid hyperplasia occurs

Answer 8

sporadically or as component of mEN

Question 9

parathyroid hyperplasia
glands involved
combined weight

Answer 9

classically all 4 glands***

combined weight of all glands is rarely over 1 gm

Question 10

parathyroid carcinoma

Answer 10

rare

need invasion of surrounding tissues and or metastaiss for dx

Question 11

what can be used to visualize parathyroid ademoma

Answer 11

sestamibi scan

Question 12

skeletal system pathology from increased PTH

Answer 12

osteoporosis

brown tumors: microfracture and secondary hemorrhages, brown from vascularity, hemorrhage, hemosiderin deposition

osteitis fibrosa cystica (severe hyper PT, rare)
-increased osteoclast activity, peritranecular fibrosis, and cystic brown tumors

Question 13

other organ pathology of hyper PTH besides bone

Answer 13

nephrolithiasis (urinary tract stones)

nephrocalcinosis

• calcification of renal interstitium and tubules
• can be seen in stomach, lungs, myocardium and BVs

Question 14

the most common cause of symptomatic hypercalcemia

Answer 14

malignancy

Question 15

what malignancies in hypercalcemia of malignancy

Answer 15

multiple myeloma
solid tumors
-lung, breast, head and neck, renal

Question 16

symptoms of primary hyperparathyroidism

Answer 16

bones
stones
abdominal groans
psychic moans

neuromuscular wekness and fatigue
cardiac: aortic and or mitral valve calcifications

Question 17

symptoms of primary hyperparathyroidism: renal

Answer 17

nephrolithiasis

• pain and obstructive uropathy
• chronic renal insufficiency and abnormalities in renal function: polyuria and secondary polydipsia

Question 18

secdonary hyperparathyroidism is usually from

Answer 18

renal failure

also inadequate dietary intake of calcium, steatorrhea, and vitamin D deficiency

Question 19

morphology of secondary hyperparathyroidism

Answer 19

hyperplastic parathryoid glands (decreased fat)
-can be asymmetric

increased number of chief cells
-diffuse or multinodular

metastatic calcifications can be seen in lungs, heart, stomach, and BVs

Question 20

clinical course of secondary hyperparathyroidism

treatment

Answer 20

calciphylaxis: vascular calcification–> ischemic damage to skin and other organs
tx: vitamin D supplements and phosphate binders

Question 21

tertiary hyperparathyroidism

treatment

Answer 21

occasionally in pts with secdonary hyperparathyroidism

parathyroids become autonomous and excessive (function independently after chronic renal failure and stimulation)

tx: remove parathyroids

Question 22

hypoparathyroidism causes

Answer 22

surgically induced from a thyroidectomy (accidental removal)

autoimmune: assocaited with chronic mucocutaneous candidiasis and primary adrenal insufficiency (APS1)

autosomal dominant hypoparathyroidism
-GOF in CASR

familial isolated hypoparathyroidism

congenital absence of glands (digeorge)

Question 23

signs of hypocalcemia

Answer 23

tetany (tingling of distal extremtiies)
-when severe can have life threat laryngospasm and seizures

chvostek sign

trousseau sign

mental status changes: emotional instability, anxiety, depression, confucion, hallucination, psychosis

Question 24

clincial manifestations of hypocalcemia

Answer 24

paradoxical calcifications (likely from increased phosphate levels)

• basal ganglia–> parkinsonian-like movement disorder
• lens and cataract formation

heart: conduction defect: pronlonged QT on ECG

dental abnormalities when hypocalcemia present during early development

Question 25

pseudohypoparathyroidism

cause
PTH levels
presents as what lab levels
also resitance to what bc of what

Answer 25

end organ resistance to PTH

serum PTH levels normal or elevated

presents as hypocalcemia and hyperphosphatemia

can also have end organ resitance to pTH, TSH and FSH/LH
-from genetic defects in GPCR