Bones Flashcards

1
Q

Factors that increase calcium (2)

A

PTH

Calcitriol (activated vitamin D)(1,25-(OH)2D3)

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2
Q

Factors that decrease calcium

A

Calcitonin

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3
Q

Where is calcitonin synthesised

A

parafollicular cells

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4
Q

Describe the synthesis of calcitriol

A

Vitamin D from diet and UV light
25 hydroxylase in the liver converts it to 25-hydroxyD3
1alpha hydroxylase and PTH in the kidneys convert it to calcitriol

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5
Q

Where does PTH have its effects

A

Kidneys
Bone
Small intestines

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6
Q

Where does calcitriol have its effects

A

Kidneys
Bone
Small intestines

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7
Q

Effect of PTH in the kidneys (3)

A

1α-hydroxylase stimulation
Increased calcium reabsorption
Increased phosphate excretion

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8
Q

Effect of PTH in the bone

A

Increased bone resorption

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9
Q

Effect of PTH in the small intestines (2)

A

Increased calcium absorption

Increased phosphate absorption

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10
Q

Effect of calcitriol in the kidneys (2)

A

Increased calcium reabsorption

Decreased phosphate reabsorption

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11
Q

Effect of calcitriol in bone

A

Increased bone formation

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12
Q

Effect of calcitriol in the small intestines (2)

A

Increased calcium absorption

Increased phosphate absorption

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13
Q

Resultant effect of PTH

A

↑ Calcium

↓ Phosphate

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14
Q

Resultant effect of calcitriol

A

↑ ↑ Calcium

↓ Phosphate

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15
Q
  1. Which hormone decreases blood calcium levels?
A

Calcitonin

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16
Q
  1. Which hormone, out of PTH and calcitriol, raises blood calcium levels the most?
A

Calcitriol

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17
Q
  1. Which enzyme does PTH activate in the kidneys?
A

1α-hydroxylase

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18
Q
  1. What does PTH do to your blood phosphate levels?
A

Decreases

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19
Q
  1. Why may the UK population be generally vitamin D deficient?
A

Less sunlight (UV)

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20
Q

What decreases PTH production

A

Calcitriol and increased calcium

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21
Q

What happens in primary hyperparathyroidism

A

Autonomous secretion of PTH uninhibited by calcium

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22
Q

What happens in secondary hyperparathyroidism

A

Physiological response to hypocalcaemia

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23
Q

Signs of hypocalcaemia (4)

A

CATs go numb

Convulsions
Arrhythmias (e.g. prolonged QT interval)
Tetany
Paraesthesia (hands, mouth, feet, lips)

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24
Q

What are the signs you can elicit in hypocalcaemia (2)

A

Trousseau’s sign

Chvostek’s sign

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25
Q

Signs of hypercalcaemia (6)

A

”Stones, bones, thrones, abdominal moans, psychiatric overtones”

Renal stones
Bone pain/damage
Polyuria
Abdo upset (nausea, constipation, pain)
Psychiatric conditions (depression, anxiety)

AND PANCREATITIS!

26
Q

RF for PHPT (3)

A

MEN-1 or MEN-2

Hypertension

27
Q

Which s/s are seen in PHPT

A

Signs and symptoms
Often asymptomatic
Hypercalcaemia:

”Stones, bones, thrones, abdominal moans, psychiatric overtones”

28
Q

Causes of secondary SHPT (3)

A

Vitamin D deficiency
(Poor dietary intake
Poor sunlight Malabsorption)

Chronic kidney disease
Liver disease

29
Q

Signs and symptoms of SHPT (4)

A

Fractures/bone pain
Proximal myopathy
Fatigue
Hypocalcaemia:

  ”CATs go numb”

Rickets in children

30
Q

Causes of proximal myopathy (3)

A

COT = Cushing’s, osteomalacia, thyrotoxicosis

31
Q
PHPT:
Calcium
Phosphate
PTH
Vit D
ALP
A
Calcium: increased
Phosphate: decreased
PTH: increased (or normal)
Vit D: normal
ALP: increased (or normal)
32
Q
Osteomalacia (vit D deficiency):
Calcium
Phosphate
PTH
Vit D
ALP
A
Calcium: decreased
Phosphate: decreased
PTH: increased
Vit D: decreased
ALP: increased
33
Q
Osteomalacia (CKD):
Calcium
Phosphate
PTH
Vit D
ALP
A
Calcium: decreased
Phosphate: increased
PTH: increased
Vit D: decreased
ALP: increased
34
Q

Bloods (9) and imaging (and why, 3) for hyperparathyroidism

A

X-rays/CT (extent of bone disease)
CT KUB (for renal stones)
Cervical U/S (before surgery)

35
Q

Mx of acute hypercalcaemia in PHPT (2)

A

IV fluids

Bisphosphonates (if calcium remains high)

36
Q

Mx of acute hypocalcaemia in SHPT

A

IV calcium infusion

(calcium gluconate)

37
Q

What is calcium gluconate used for

A

Hyperkalaemia

Hypocalcaemia

38
Q

Mx of PHPT (not acute)

A

Surgical (1st line)
Total parathyroidectomy

Medical
Cinacalcet
(if unsuitable for surgery)
(drug class: calcimemetic)

39
Q

Mx of SHPT (not acute)

A

Medical
Calcium
Vitamin D (inactive - ergocalciferol)

40
Q

Mx of osteomalacia due to CKD

A

Treat CKD
Calcium
Vitamin D (active - alfacalcidol)

41
Q
A 63 year old man is furious that he has been waiting an hour for his appointment. When he finally talks to the doctor, he admits to generalised bone pain and muscle weakness. His blood results reveal the following:
Calcium
2.08 mmol/L (2.1-2.6)
Phosphate
0.74 mmol/L (0.8-1.4)
ALT
29 iu/L (3-40)
ALP
343 umol/L (30-100)

Whats the diagnosis

A

Osteomalacia (vit D deficiency)

42
Q
A 75 year old woman presents with polyuria, constipation. She admits that her mood has been low over the past few weeks. Her blood results reveal the following:
Calcium
2.88 mmol/L (2.1-2.6)
Phosphate
0.75 mmol/L (0.8-1.4)
PTH
5 pmol/L (0.8-8.5)
Fasting glucose
4.5 mmol/L

Diagnosis?

A

Primary hyperparathyroidism

43
Q

Define Pagets disease

A

disorder of bone remodelling (i.e. formation and resorption) – genetic factors play a role

44
Q

What are the three phases of Paget’s disease

A
1. Lytic phase
Hyperactive osteoclasts -> resorption
2. Mixed phase
Compensation by osteoblasts
3. Sclerotic phase
Hyperactive osteoblasts -> formation
(woven bone, not lamellar)
45
Q

RF of Paget’s disease

A

Elderly

FHx

46
Q

Symptoms of Paget’s disease (2 main causes of presenting)

A
Often asymptomatic
Bone pain (insidious onset)
      	Femur
      	Pelvis
	Skull
Nerve compression
      	Hearing loss (sensorineural)
	Sciatica
47
Q

Signs of Paget’s disease (3)

A
Bone bossing
	Skull
	Femur
	Tibia 
Thoracic kyphosis
Warm skin over painful area (high metabolic activity)
48
Q
Pagets disease:
Ca
PO4
PTH
Vit D
ALP
A
Ca2+
normal
PO43-
normal
PTH
normal
Vit D
normal
ALP
↑
49
Q

Ix for Pagets disease (11)

A
Bloods
(FBC, CRP)
U&E
LFTs (ALP)
Calcium
Phosphate
PTH
Vitamin D
Serum CTX (bone resorption marker)
Serum P1NP (bone formation marker)

Imaging
X-rays
Bone scan (Tec99)

50
Q

Which special Ix for Pagets (3)

A
Serum CTX (bone resorption marker)
Serum P1NP (bone formation marker)
Bone scan (Tec99)
51
Q

Define osteoporosis

A

Definition: reduced bone density

52
Q

Causes of primary osteoporosis

A
Post-menopausal
Old age (>50 years
53
Q

Causes of secondary osteoporosis (5 main ways)

A
Drugs – steroids, thyroxine
Endo – Cushing’s disease, osteomalacia, hyperT
Cancer – multiple myeloma
MSK – SLE, rheumatoid arthritis
GI – coeliac disease, IBD
54
Q

Drugs that can cause osteoporosis (2)

A

Steroids, thyroxine

55
Q

Endo problems that can cause osteoporosis (3)

A

Cushing’s disease, osteomalacia, hyperthyroidism

56
Q

Cancers that can cause osteoporosis

A

MM

57
Q

MSk problems that can cause osteoporosis (2)

A

SLE, RA

58
Q

GI problems that can cause osteoporosis (2)

A

coeliac disease, IBD

59
Q

Imaging for osteoporosis

A

DEXA scan

60
Q

What is a T score and what is a Z score in osteoporosis

A

T-score: Patient’s BMD compared to young, healthy adult

Z-score: Patient’s BMD compared to age-matched BMD

61
Q

What are the different classifications of osteoporosis

A

Normal 0
Osteopaenia -1–2.5
Osteoporosis >2.5

62
Q
Calcium
3.8 mmol/L (2.1-2.6)
Phosphate
0.74 mmol/L (0.8-1.4)
PTH
6.6 pmol/L (0.8-8.5)
ALP
46 umol/L (30-100)

What does this show?

A

PHPT - PTH is inappropriately normal