Hyperparathyroidism

Question 1

Which cells secrete PTH?

Answer 1

• Chief cells in parathyroid gland

Question 2

What is the function of PTH?

Answer 2

• Increase plasma Ca
  
  • increase osteoclast activity
  • increase Ca reabsorption and phosphate secretion in kidney
  • increase active vit D (calcitriol) production

Question 3

What is the alternative form of calcitriol?

Answer 3

1,25-dihydroxycholecalciferol

Question 4

What are the causes of hyperparathyroidism?

Answer 4

• Primary
  
  • solitary tumour of parathyrid gland (common)
  • hyperplasia
• Secondary
  
  • CRF
  • Vit D defficiency
• Tertiary
  
  • prolonged secondary hyperparathyroidism
• Malignant hyperparathyroidism
  
  • PTHrP by squamous cell lung cancer, breast cancer, renal cancer

Question 5

What are the Sx of hyperparathyroidism?

* remember stones, bones, groans, thrones and psychiatric moans

Answer 5

• Renal stones
• Bone pain
• N&V, constipation
• Fatigue, depression, psychosis

Question 6

What are the features of primary hyperparathyroidism?

Answer 6

• Sx
  
  • asymptomatic (common)
  • hyperparathyroidism sx
  • high BP
• Ix
  
  • high cal
  • high PTH
  • low phosphate
• Imaging
  
  • osteitis fibrosa cystica
  • Dexa - for osteoporosis

Question 7

What are the features of osteitis fibrosa cystica?

Answer 7

• subperiosteal erosions
• cyst
• brown tumours of phalanges
• acro-osteolysis

Question 8

What are the features of secondary hyperparathyroidism?

Answer 8

• High PTH
• low - normal Ca

Question 9

What are the features of tertiary hyperparathyroidism?

Answer 9

• High PTH
• High Ca

Question 10

How would you mx hyperparathyroidism?

Answer 10

• Primary and tertiary
  
  • Surgically remove parathyroid gland
• Sedcondary
  
  • treat underlying cause

Question 11

What are the features of malignant hyperparathyroidism?

Answer 11

• low PTH
• PTHrP not detected in assay

Question 12

What are the recommendation referral for consideration of parathyroid surgery?

Answer 12

• Symptoms of hypercalcaemia (e.g. thirst, polyuria, constipation)
• End-organ disease (renal calculi, fragility fractures or osteoporosis)
• Corrected serum calcium of 2.85 mmol/L or above