Hypoparathyroidism

Question 1

Primary hypoparathyroidism

Answer 1

decrease PTH secretion
e.g. secondary to thyroid surgery*
low calcium, high phosphate
treated with alfacalcidol

Question 2

The main symptoms of hypoparathyroidism are secondary to hypocalcaemia:

Answer 2

tetany: muscle twitching, cramping and spasm

perioral paraesthesia

Trousseau’s sign: carpal spasm if the brachial artery occluded by inflating the blood pressure cuff and maintaining pressure above systolic

Chvostek’s sign: tapping over parotid causes facial muscles to twitch

if chronic: depression, cataracts

ECG: prolonged QT interval

Question 3

Pseudohypoparathyroidism

Answer 3

target cells being insensitive to PTH

due to abnormality in a G protein

associated with low IQ, short stature, shortened 4th
and 5th metacarpals

low calcium, high phosphate, high PTH

diagnosis is made by measuring urinary cAMP and phosphate levels following an infusion of PTH. In hypoparathyroidism this will cause an increase in both cAMP and phosphate levels. In pseudohypoparathyroidism type I neither cAMP nor phosphate levels are increased whilst in pseudohypoparathyroidism type II only cAMP rises.

Question 4

Pseudopseudohypoparathyroidism

Answer 4

similar phenotype to pseudohypoparathyroidism but normal biochemistry

Question 5

Hypoparathyroidism specific signs on a patient?

Answer 5

dry, scaly, puffy skin, brittle nails, coarse hair

Question 6

Pseudohypoparathryoidism specific signs of a patient?

Answer 6

short stature, short neck and short 4th and 5th metacarpals