Parathyroid

Question 0

What do the lower parathyroids develop from?

Answer 0

3rd branchial pouch

Below level of inferior thyroid artery usually at inferior pole of thyroid gland

Question 1

Most common cause of primary hyperparathyroidism ?

Answer 1

Adenoma - 80%

Question 2

How are parathyroid adenoma’s localised?

Answer 2

1. Technitium thallium scan
2. Sestamibi scan nuclear scan
3. Selective venous catheterisation
4. PTH assay

Question 3

What is the thymus derived from?

Answer 3

3rd pharyngeal pouch

Question 4

What happens in DiGeorges syndrome?

Answer 4

The 3rd and 4th pharyngeal pouches fail to develop

Question 5

What does PTH do?

Answer 5

1. Increase bone resorption - stimulation of osteoclast
2. Increase calcium reabsorption in Distal tubule
3. Decreased reabsorption of phosphate in proximal tubule
4. Increased phosphate excretion in urine

Question 6

Signs of high calcium?

Answer 6

1. Dyspepsia
2. Polyuria
3. Nocturia
4. Constipation
5. Depression

Question 7

Vitamin D

Answer 7

1. 1,25-DihydroxycholeCalciferol - active form of vitamin D
2. Produced in proximal tubule
3. Stimulates calcium absorption in small intestine and renal absorption of calcium

Question 8

Superior parathyroid

Answer 8

Forth branchial pouch

First trachial ring at the level where the recurrent laryngeal nerve crosses inferior thyroid artery

Question 9

Blood supply to parathyroid

Answer 9

Inferior thyroid artery

Question 10

Venus drainage of parathyroid

Answer 10

Thyroid venous plexus to left brachiocephalic vein

Question 11

What type of cell produces parathyroid hormone

Answer 11

Chief cell

Question 12

What is the half life of parathyroid Hormone

Answer 12

2-5min

Degraded liver circulation and kidney

Question 13

Secondary hyperparathyroidism

Answer 13

1. Renal failure
2. Malabsorption
   Normocalcaemia
   Elevated phosphate
   Elevated parathyroid hormone

Question 14

Tirtiary hyperparathyroidism

Answer 14

Parathyroid gland becomes hyperplastic due to secondary hyperparathyroidism and continues to produce parathyroid hormone in the presence of normal calcium levels

Question 15

Bone alkaline phosphatase

Answer 15

Glycoprotein found on surface of osteoblasts

Question 16

Vitamin D excess

Answer 16

High calcium
High Phosphate
Low parathyroid hormone

Question 17

Pagets disease

Answer 17

Normal calcium and phosphate
High alkaline phosphatase
Normal Parathyroid hormone

Question 18

Osteomalacia

Answer 18

Lowish to normal calcium
Low phosphate
High Alkaline phosphatase
High parathyroid hormone

Question 19

Hypoparathyroidism

Answer 19

1. Paresthesia in lips (circumural numbness) and fingers
2. Carpopedal spasm
3. Tetany
4. Cramps
5. Dystonia
6. Psychosis
7. Chvostec sign
8. Trousseau sign
9. Prolonged QT

Question 20

Chvostec sign

Answer 20

Twitching of facial muscle

Question 21

Trousseaus sign

Answer 21

Spasm of fingers and wrist when when BP cuff is tightened for 3 min at 10-20mmhg higher than systolic BP

Question 22

Treatment of hypocalcaemia

Answer 22

10ml of 10% calcium gluconate over 5min (0.05mmol/kg/hr)