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Flashcards in Bone and Biochemistry Deck (41):
1

Summary of Bone Pathology

Bone composition/cells
Investigations of Bone disease

Bone Diseases:
-Osteoporosis
-HPT
-Paget's, -Osteomalacia/Rickets
-Mets

Ca/Mg/Pi homeostasis

2

State 4 functions of bone.

Structural support
Protection
Produce blood cells
Store minerals (esp Ca)

3

Bones are HIGHLY VASCULAR & are constantly remodelling. Describe the 4 structural components of bone.

Outer: Cortical bone
Inner: Trabecular bone
Cells: (3)
ECM: Ca + minerals = hydroxypatitie

4

Which bone cell produces hormones to comm with other bone cells & produces osteoid?

Osteoblast

5

Markers for osteoblast activity and therefore bone formation?

P1NP
ALP

6

Which bone cell regulated ECM turonver & has mechanosensory properties?

Osteocytes

7

Osteoclasts breakdown bone and have a ruffled border. What regulates them?

PTH
Clacitonin
IL-6

8

As we age our bone becomes less dense. Who are most suseptibly to a quicker decrease in bone density and therefore osteoporosis?

Early menopause women

9

State 4 commonly used investigations in bone disease.

X-ray (gross)
DEXA (density)
Bone markers
Biopsy

10

Name the bone formation and bone resorption markers.

Bone formation: P1NP,
ALP (also in HPT, growth spurt, preg, fractures, Paget's

Bone resorption: CTX, NTX (increases in periods of high bone turnover)

11

DEXA uses radiation through which bones to assess density?

Lumbar spine
Hip

12

A T-score in DEXA of

OSTEOPOROSIS

13

A normal T-score in DEXA is over what value?

> -1

14

Osteoporosis has numerous risk factors. List 5 main ones.

Female
Early menopause
Smoking
Alcohol
Long-term steroids
Vit D def
UC
RA
UC

15

2" causes of osteoporosis involve conditions from which systems?

Endocrine
GI
Haematological
Respiratory
RA
CKD
Drugs

16

Osteoporosis presents as increase biconvavity in T vertebral bodies, vertebral fractures and a hunched back. T/F?

T

17

Common complication of osteoporisis is...?

Fragility fractures

FRAX tool

18

Bone mets can be lytic or osteoblastic. Presentation?

Signs of hypercalcaemia
Pain
Pathological fractures
Numbness/paralysis, diff urinating (sc mets*)

19

1" HPT is often seen in Females, >45yrs. What are the 4 possible causes?

Adenoma
Parathyroid carcinoma (rare)
Glandular hyperplasia
Ectopic adenoma

20

1" HPT is often ASYMPTOMATIC. What are other possible presentations?

Symptoms of hypercalcaemia

Renal: stones, CKD

Bone: Osteoporosis

Proximal muscle wasting

21

Investigations for 1" HPT?

Imagine: Tc99 Sestambi

Biochemistry (high PTH, high ca, low Pi, High ALP)

22

Treatment for 1" HPT?

Calcimimetics
Surgery

23

2" HPT is caused by what?

Vit D def
CKD (kidneys activate Vit D)

(High PTH, Low Ca)

24

Which type of HPT is present in prolonged 2" HPT (usually CKD)?

3" HPT

25

Which type of HPT is present in prolonged 2" HPT (usually CKD)?

3" HPT

26

The presentation of hypercalcamaemia is described using what mneumonic?

BONES, STONES, GROANS & MOANS

27

Mild symptoms of hypercalcaemia?

Polyuria/Polydispia
Anorexia
Nausea
Constipation
Mood changes

28

Severe symptoms of hypercalcaemia?

Abdo pain
Vomiting/dehydration
Pancreatitis
Arrthymias
Coma

29

State the most common non-PTH and PTH mediated causes of hypercalcaemia.

Non-PTH - malignancy
(Sarcoidosis, hyperthyroid, acromegaly)

PTH - 1" HPT

30

Vit D def, hypoparathyroidism, Hypoproteinaemia, Reduced dietary intake and EDTA contamination can all cause what?

Hypocalcaemia

31

Ca is needed for what functions?

Muscle contraction
Neuronal excitability
Blood clotting
Enzyme activity
Bone ECM

32

[Ca] is regulated by the Kidneys/Gut/Bone. What 2 molecules also feature in Ca metabolism?

PTH
Vit D

33

Does Acidosis lead to hypercalcaemia or hypocalcaemia?

Hypercalcaemia

H+ displaces Ca

34

Mg is an intracellular ion that is essential in metabolism of what other ions?

Ca - Releases PTH

K+ - reabsorption in kidneys

*ALWAYS CONSIDER HYPOKALAEMIA/HYPOCALCAEMIA with Mg def*

35

Mg is used for what in the body..?

Neuromuscular excitation
Cofactor ATP
Enzyme activity
Aids PTH release
Aids K+ reabsorption

36

Name 3 causes of hypomagnesia.

(common in hospitals)

Renal
Drugs: Gentamicin, chemo, Diuretics
GI: Malnutrition/Malabsorption, IV nutrition, diarrhoea

37

Hypomagnesia can cause muscle weakness, decrease CV contractility, ataxia, hyperreflexia etc.. T/F?

T

38

Phosphate is an intracellular ion involved in intracellular signalling. What are some of its functions?

ATP component
Cellular metabolism
DNA backbone
Bone ECM
Cell membrane

39

What hormone controls [Pi]?

PTH

Promotes excretion

40

Pi def can lead to muscle weakness, general cellular dysfunction. Severe def can lead to what?

RESPIRATORY FAILURE

41

Causes of Pi def?

HPT
Reduced dietary intake
Excess loss: renal, GI, Diabetes (diuresis)
Refeeding syndrome