parathyroid physiology + diseases Flashcards
what are parathyroid composed of
chief cells
supported by oxyphil cells
what doe chief cells secrete
PTH
describe chief cells
round cells with a moderate cytoplasm and a bland, central nuclei.
describe oxyphil cells
slightly larger which acidophilic cytoplasm
what are the 3 types of hyperparathyroidism
primary
secondary
tertiary
what causes tertiary hyperparathyroidism
parathyroid activity become autonomous
what is tertiary hyperparathyroidism associated with
hypercalcaemia
what hormone levels would you expect in tertiary hyperparathyroidism (Ca and PTH)
high Ca
high PTH
what causes primary hyperparathyroidism, what is most common
small adenoma = most common
hyperplasia
carcinoma
what hormone levels would you expect in primary hyperparathyroidism (Ca and PTH)
high Ca
high PTH
what causes secondary hyperparathyroidism
renal failure
low ca intake
vit D deficiency
what hormone levels would you expect in secondary
hyperparathyroidism (Ca and PTH)
low Ca
high PTH
what is secondary hyperparathyroidism
physiological response to low Ca or it D
what is primary hyperparathyroidism
overactivity of the parathyroid gland
what is the investigation of hyperparathyroidism
sestamibi scan
what are the symptoms of hyperparathyroidism
bone disease renal stones + complications muscle weakness + fatigue calcification of valves constipation gall stones pancreatitis
what are the treatments of hyperparathyroidism
surgery
cinacalcet
when is surgery indicated
end organ damage
very high calcium >2.85
under 50
eGFR <60
what treatment would you give in hyperparathyroidism if they are unable to tolerate surgery
cinacalcet
what is cinacalcet
calcium mimic
what causes hypoparathyroidism
post-op
Di George syndrome
hypomanagnesaemia
what are the symptoms of hypoparathyroidism
Tetany - Neuromuscular irritability - Chvostek’s sign - Trousseau’s sign Altered mental state Calcification of lens and cataract formation Prolonged QT interval Dental abnormalities if it occurs during development
what is the treatment of hypoparathyroidism
calcium supplements
vit D supplements
give examples of it D supplements
tablets
alphacalcidol
depot injections
what causes pseudohypoparathyroidism
genetic defect in the Gs alpha subunit within GNAS1
what hormone levels would you expect in pseudohypoparathyroidism
low Ca
high PTH
