Bone Disorders

Question 1

Regulation of calcium is by?

Answer 1

Vitamin d 25 and PTH

Question 2

Leak of calcium by?

Answer 2

EcaC1 TRPV5 in kidney and EcaC2, TRPV6 in intestine

And pump basolateral calcium ATPase PMCA1b

Question 3

EcaC expression is activated by?

Answer 3

1,25 VitD

Through gene transcription and phosphorylation of channels
And insertion of EcaC rich vesicles

Question 4

Activation of vit D 1 alpha hydroxylation done by?

Answer 4

In kidney by PTH

Question 5

As Phosphate increases, PTH

Answer 5

INCREASES

Question 6

PTh half life

Answer 6

4 mins

Question 7

Low magnesium causes?

Answer 7

Inhibits PTH release

Question 8

Humeral hypercalcaemia malignancy caused by?

Answer 8

PTHrP

Question 9

Enzymes for activation of cholecaciferol?

Answer 9

Renal 1 alpha hydroxylase and 25 hydroxylase

Question 10

Calcitonin effect?

Answer 10

Reduce bone resorption

Question 11

FGF23?

Answer 11

Reduced phosphate reabsorption in the renal proximal tubule and inhibits 1 alpha hydroxyase

Question 12

Phosphate is secreted by?

Answer 12

Osteocytes, osteoblasts and osteoclasts

Question 13

FGF23 can cause?

Answer 13

Reduction is phosphate reabsorption in renal proximal tubule, and inhibits 1 alpha hydroxylase

Question 14

How much of calcium is ionised?

Answer 14

50%

Question 15

What can total calcium be changed by?

Answer 15

Changes in albumin

Question 16

Range for calcium is?

Answer 16

2.20 and 2.60 mmol/L

Question 17

Hypercalcaemia with suppressed PTH is caused by?

Answer 17

Malignancy of blood, lung and breast, vit D excess and sarcoidosis

Question 18

Hypercalcaemia with raised PTH caused by?

Answer 18

1 or 3 hyperparathyroidism or defects in calcium receptors FHH

Question 19

Hypocalcaemia and increased PTH?

Answer 19

Vitamin D deficiency, malabsorption, renal failure, PTH receptor defect and vit D receptor defect

Question 20

Hypocalcaemia and low or normal PTH?

Answer 20

Hypoparathyroidism, congenital Digeorge
Post surgery radiotherapy
Mg deficiency

Question 21

What can cause Polyuria?

Answer 21

Diabetes insipidus and mellitus

Renal failure, high calcium and low potassium

Question 22

How does calcium cause polyuria?

Answer 22

Inhibits Gs preventing ADH on V2 receptor to absorb water via luminal AQP2 insertion

Question 23

Familial hypocalciuria hypercalcaemia is genetically?

Answer 23

Autosomal dominant, loss of function of calcium receptor

Question 24

To exclude FHH you would

Answer 24

Ca:cr ratio over 0.01

Question 25

MEN1 is for 3Ps?

Answer 25

Pituitary adenoma, Parathyroid hyperplasia Pancreatic tumours Cause primary hyperparathyroidism is uncommon in younger people

Question 26

MEN2 is for 3cs?

Answer 26

Calcitonin: Medullary thyroid carcinoma Calcium: Parathyroid hyperplasia Catecholamines: Pheochromocytoma

Question 27

Calcitonin is used to distinguish between?

Answer 27

C cell hyperplasia from medullary c cell carcinoma, Pentagastrin stimulated values should be used

Question 28

Problems with CKD mineral bone disease 3 hyperparathyroidism?

Answer 28

Reduced glomerular filtration of phosphate and impaired renal tubular response leads to phosphate retention Reduced renal mass causing less activity of 1a hydroxylase so failure to increase calcitrol

Question 29

Pseudohypoprathyroidism?

Answer 29

PTH resistance GNAS heterozygous mutation , G protein that couples the PTH receptor to adenylate cyclase

Question 30

Pseudohypoparathyroidism- Albright hereditary osteodystrophy phenotype?

Answer 30

Short stature, short 4/5 metacarpals and or metatarsals, round facies obesity and mild mental retardation

Question 31

Weird aspect of pseudohypoparathyroidism?

Answer 31

If mutant gene from mum then biochemical and physical features- genetic imprinting If from father only physical features- PTH receptor not in kidney

Question 32

Genetic imprinting?

Answer 32

Only a maternal or paternal gene is imprinted and not both

Question 33

Pagets disease?

Answer 33

Dysregulated bone growth, immobilisation Hypercalcaemia High ALP

Question 34

Calcium alkali syndrome?

Answer 34

Triad of hypercalcaemia, metabolic alkalosis and AKI renal insufficiency due to ingestion of large amounts of calcium and absorbable alkali

Question 35

How do sarcoidosis cause hypercalcaemia?

Answer 35

Granulomas produce ACE, and a1 hydroxylase activates vit D

Question 36

EDTA contamination causes what?

Answer 36

Chelation of ions such as calcium, magnesium and zinc ALP needs zinc as cofactor so low activity

Question 37

Difference between diabetes insipidus and mellitus?

Answer 37

In mellitus blood glucose levels are high

Question 38

ECaC2 can be found in?

Answer 38

Intestine

Question 39

ECaC1 can be found in?

Answer 39

Kidney

Question 40

What does active vitamin D do?

Answer 40

Gene transcription, phosphorylation of channels and insertion of ECaC rich vesicles

Question 41

Low magnesium does what?

Answer 41

Inhibits release of PTH

Question 42

What does PTHrP do?

Answer 42

Stimulated transport of calcium across placenta | Contributes to the bone loss during lactation

Question 43

What is calcitonin a marker for?

Answer 43

Tumour marker for medullary carcinoma of thyroid

Question 44

Adjusted calcium equation?

Answer 44

Calcium + 0.02* (40-albumin)

Question 45

Normocalcaemia hyperparathyroidism causes?

Answer 45

Primary hyperparathyroidism, vit D deficiency, CKD, acute illness, malabsorption dietary and drugs

Question 46

High ALP can be suggestive of?

Answer 46

Hyperparathyroidism

Question 47

FHH equation

Answer 47

Urine calcium x plasma creatnine/1000 Over Calcium plasma x urine creatnine

Question 48

Sarcoid is?

Answer 48

Inflamed cells clump otgether to make small lumps called granulomas

Question 49

PTH responds to?

Answer 49

fall in plasma ionised calcium (acute) | - rise in plasma phosphate (chronic)

Question 50

What is the main tumour marker for medullary carcinoma of the thyroid?

Answer 50

Calcitonin

Question 51

Normocalcaemic hyperparathyroidism causes?

Answer 51

``` Primary hyperparathyroidism Vit d deficiency CKD- low 1,25 D, high PTH due to hyper phosphataemia Acute illness Malabsorption Drugs ```

Question 52

What is the Ca:Cr ratio?

Answer 52

Urine calcium x plasma creatinine / Plasma calcium x urine creatnine