General

Question 1

Symptoms of hypocalcemia

Answer 1

‘Without calcium, CATs go numb’

Convulsions
Arrhythmias
Tetany

Numbness

Question 2

Functions of extra cellular calcium in the body

Answer 2

Neuron action potentials
Muscle contraction
Hormone secretion
Blood coagulation

Question 3

Three effects of parathyroid hormone

Answer 3

1. Gets bones to release calcium
2. Gets kidneys to reabsorb more calcium, so it’s not lost in the urine
3. Gets kidneys to synthesise calcitriol (active vitamin D aka 1,25-digydroxycholecalciferol), Calcitriol increases blood calcium by increasing the uptake of calcium from the intestines

Question 4

Symptoms of Hypercalcemia

Answer 4

‘Stones, bones, groans, thrones and psychiatric overtones!’

Stones - renal or biliary stones. Hypercalciuria → dehydration → calcium oxalate kidney stones

Bones - bone pain

Groans - abdominal discomfort, constipation (due to muscle weakness)

Thrones - nausea, vomiting, excessive urination

Psychiatric overtones - altered mental status, confusion, hallucinations

General: Slower or absent reflexes

Slow muscle contraction → constipation, muscle weakness

Question 5

Causes of hypercalcemia

Answer 5

High levels of osteoclastic bone resorption
Excess PTH
Malignancy
Excess vitamin D - too much calcium absorbed in the gut
Thiazide diuretics - increase calcium resorption in distant tubule of kidney
Hyperalbuminemia

CHIMPS

Cancer
Hyperparathyroidism
Intoxication of Vitamin D / Idiopathic
Milk alkali syndrome / Multiple myeloma
Paget’s disease
Sarcoidosis 

Milk alkali syndrome can be caused by excessive anti-acid consumption (calcium carbonate eg Gaviscon)

Question 6

Name and describe 4 types of benign bone tumour

Answer 6

Question 7

Name and describe 3 types of malignant bone tumour

Answer 7

Question 8

Describe the process of bone remodelling

Answer 8

1. OsteoBlasts release RANKL
2. RANKL binds to RANK receptors on osteoclasts, which activates them to secrete lysosomal enzymes like collagenase and hydrochloride acid
3. Once there has been enough bone breakdown, osteoBlasts secrete OPG (osteoprotegerin) which binds RANKL and prevents it binding RANK receptors , so osteoClasts stop demineralising bone.
4. OsteoBlasts secrete osteoid seam (collagen) which acts as a scaffold upon which calcium and phosphate can get deposited, new bone begins to form again

Question 9

Who cannot have an MRI?

Answer 9

Cardiac pacemakers (some types might be ok?)
Intracranial aneurysm clips
Intraocular foreign bodies
+ more