Hypoparathyroidism

Question 1

What is hypoparathyroidism

Answer 1

Hypoparathyroidism is caused by relative or absolute deficiency of plasma parathyroid hormone (PTH) synthesis and secretion. This leads to low albumin-corrected serum total calcium and elevated serum phosphate.

Question 2

What are causes of primary hypoparathyroidism

Answer 2

Gland failure e.g. Di George syndrome, autoimmune,

Question 3

What are causes of secondary hypoparathyroidism

Answer 3

radiation or surgery, most commonly thyroidectomy.

Question 4

What is Pseudohypoparathyroidism

Answer 4

failure of target cell response to PTH.

Question 5

What are Sx of hypoparathyroidism

Answer 5

Low calcium:
• Muscle cramps 
	• Spasms and twitches
	• Paraesthesia, numbness, and tingling
	• Poor memory and slowed thinking 
	• Anxiety
Dry hair and brittle nails

Question 6

What Ix in hypoparathyroidism?

Answer 6

PTH: low

Ca: low, PO4 high

Mg: Magnesium deficiency exacerbates hypocalcaemia and impairs PTH secretion.

ECG: Prolonged QT interval indicates severe life-threatening hypocalcaemia.

vitamin D often low

Question 7

What are DDx for hypoparathyroidism?

Answer 7

• Vitamin D deficiency
• Hypomagnasaemia
• Psuedo
CKD

Question 8

What is Rx for hypoparathyroidism?

Answer 8

Conservative: high Ca and low PO4 diet

Medical
For severe acute (e.g. if Ca <1.88) 
	1. IV calcium
	2. Oral Mg if deficient
	3. Treat respiratory alkalosis if present

For post-op hypocalcaemia
• Oral calcium
• Calcitriol

For ongoing hypocalcaemia
	• Oral calcium and calcitriol
	• Human recombinant PTH
	• Thiazide diuretic 
	• Oral Mg

Question 9

What drugs should be stopped in patients with hypoparathyroidism?

Answer 9

Ones which interfere with Mg and Ca absorption, or increase Ca excretion eg.

PPI
Corticosteroids
Loop diuretics

Question 10

What are complications of hypoparathyroidism?

Answer 10

• Ectopic calcifications
  
  • Cataracts
  • Hypercalcaemia
  • Renal insufficiency
  • Renal stones