Endocrine

Question 1

What percentage of calcium is in the extracellular fluid

Answer 1

1%

99% as bone

Question 2

Percentage of Ca bound to albumin

Answer 2

40%

Question 3

Plasma conc Ca

Ionised conc Ca

Answer 3

2. 2-2.6

1. 15

Question 4

Actions of PTH

Answer 4

Increase osteoclast activity - release Ca from bone

Increase reabsorption from the DCT

Reduced phosphate reabsorption

Vit D3 conversion to 1-25, di-hydroxy vit D3 –> increases GI absorption

Question 5

Actions of Calcitonin

Answer 5

Inhibit CA absorption

Inhibit osteoclasts

Stimulate osteoblasts

Inhibint tubular reabsorption of calcium

BUT ALSL reduces PO4 reabsorption

Question 6

Features of hypercalcaemia

Answer 6

Groans - constipation
Bones - pain
Moans - psychosis
Stones - kidney

Question 7

ECG features of hypercalcaemia

Answer 7

Short QTc, broad T wave

Question 8

Causes pf hypercalcaemia

Answer 8

Cancer ectopic PTH

Primary hyperparathyroid (adenoma and MEN)

Hyperthyroid

Sarcoid/TB

Li, thiazides

Rhabdo. milk alkali

Question 9

ECG of hypocalcaemia

Answer 9

Prolonged QT

Question 10

Causes of hypocalcaemia

Answer 10

Primary hypoparathyroid

Congenital deficiency - Digeorges

Resistance to PTH (pseduhypopara

Vit D deficiency

Osteomalacy

Poor intake

Furosemide, calcitonin, bisphos, amphotericin B

TLS

Rhabdo

Pancreatitis

Question 11

Features of hypocalcaemia

Answer 11

Neuromuscular irritability

Paraeathesia of hands/mouth

Tetany

Cramps

Seizures

Laryngospasm

Chovstek/Trouseau

Question 12

Range for Mg

Answer 12

0.7 to 1.0

Question 13

Features of hypermag

Answer 13

Hypotension
Brady
Drowsy
Hyporeflexia
Coma
Resp depression

Question 14

Tx of hyperphoshataemia

Answer 14

Aluminium hydroxide binds

Dialysis

Question 15

Causes of hypophosphat

Answer 15

Resp alkalosis
Refeeding
Hyperparathyroid
Decreased absorption - vit D deficiency, antacid abuse, chronic diarrhoea