hyperparathyroidism Flashcards
how many parathyroid glands are there?
4
what cells secrete PTH?
chief cells
what triggers chief cells to release PTH?
low calcium levels
what effect does PTH have?
increases Ca2+ levels
- increases absorption of Ca2+ in the intestines
- increases reabsorption of Ca2+ in the kidneys so less is excreted in the urine
- increases osteoclast activity so increase of bone being broken down and Ca2+ released into blood
- converts Vitamin D into its active form, active vitamin D also increases absorption of Ca2+ in intestines, increases reabsorption of Ca2+ in kidneys and increases osteclast activity
what effect can a vitamin D deficiency have on Ca+ levels?
-can lead to low calcium levels
what type of hyperparathyroidism are there?
- primary
- secondary
- tertiary
what causes primary hyperparathyroidism?
-a tumour in the parathyroid glands
what is the pathophysiology of hyperparathyroidism?
- there is a tumour in the parathyroid glands
- tumour leads to increased PTH
- increased PTH leads to increased osteclast activity, increased absorption of Ca2+ in the intestines and increased reabsorption of Ca2+ in kidneys leading to hypercalcaemia
what are the PTH and Ca2+ levels like in primary hyperparathyroidism?
PTH= high Ca2+ = high
what is the treatment for primary hyperparathyroidism?
1st line= surgical removal of parathyroid tumour
2nd line= cinacelet (lowers Ca2+ and PTH levels)
screen for MEN
what is the cause for secondary hyperparathyroidism?
- low Ca2+ intake
- chronic renal failure
- decrease in vitamin D intake
what is the treatment for secondary hyperparathyroidism?
chronic renal failure= sevelamer
Vit D deficiency= vit D supplement
low Ca2+= calcium supplement
what is the pathophysiology of secondary hyperparathyroidism?
- hypocalcaemia due to chronic renal disease, low Ca2+ intake or Vit D deficiency
- hypocalcaemia leads to increase PTH levels
- chronic hypocalcaemia can lead to increase baseline levels of PTH
what are the Ca2+ levels and the PTH levles like in secondary hyperparathyroidism?
- Ca2+ levels low
- PTH levels high
what causes tertiary hyperparathyroidism?
secondary hyperplasia occurred for so long that it has lead to hyperplasia of parathyroid glands causing them to secrete more PTH even when Ca2+ levels are normal
