Hypoparathyroidism

Question 1

what is hypoparathyroidism

Answer 1

insufficient PTH levels prod by parathyroid gland

Question 2

what is the main characteristic of hypoparathyroidism

Answer 2

hypocalcaemia

Question 3

describe the 4 types of hypoparathyroidism

Answer 3

congenital:
- DiGeorge syndrome (chromosome 22q11.2 deletion)

acquired:
- complication of parathyroidectomy/thyroidectomy

transient:
- neonates born prematurely

inherited:

• pseudohypoparathyroidism
• elevated PTH due to target organ resistance

Question 4

describe the presentation of hypoparathyroidism

Answer 4

depends on cause

hallmark is neuromuscular excitability followed by tetany

• abdominal and bone pain
• muscle spasm
• fatigue, headaches
• seizures
• Chvostek’s sign
• Trousseau’s sign

Question 5

explain why hypocalcaemia causes neuromuscular excitability

Answer 5

• normally Ca2+ blocks Na+ entering cells
• low Ca2+, easier for Na+ to enter cells
• causes cells to depolarise more easily

Question 6

describe Chvostek’s sign

Answer 6

• tapping on face, just anterior to ear and below zygomatic bone
• causes twitching of ipsilateral facial muscles

Question 7

describe Trousseau’s sign

Answer 7

• inflating BP cuff above SBP for several minutes

- causes muscular contraction incl. flexion of wrist and MCP joints, hyperextension of fingers, flexion of thumb on palm

Question 8

what investigations can be done in suspected hypoparathyroidism

Answer 8

bloods:
- low PTH
- hypocalcaemia
- hyperphosphataemia

• ECG and echo rule out cardiac defects
• U&E rule out CKD
• vit D level rules out deficiency

Question 9

what blood result is different in pseudohypoparathyroidism compared to hypoparathyroidism

Answer 9

PTH level is high in pseudo but low in hypoparathyroidism

Question 10

outline the management of hypoparathyroidism

Answer 10

• diet high in calcium and low in phosphate
• calcium and vit D supplements
• IV calcium gluconate in severe hypoglycaemia