Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y2 BRS Endocrinology > Calcium Dysregulation > Flashcards

Calcium Dysregulation Flashcards

1
Q

What hormones increase serum calcium and phosphate?

A
  1. Vitamin D

2. Parathyroid hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What hormone decreases serum calcium and phosphate?

A

Calcitonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the sources of Vitamin D?

A
  1. Synthesised in skin

2. Intake via diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where is PTH secreted from?

A

Parathyroid glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where do the main regulators of calcium and phosphate have actions?

A
  1. Kidney
  2. Bone
  3. Gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is calcitonin secreted by?

A

Thyroid parafollicular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an indicator of body vitamin D status?

A

Serum 25-OH vitamin D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does calcitriol regulate its own synthesis?

A

Decreasing transcription of 1 alpha hydroxylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is calcitriol?

A

1,25(OH)2 cholecalciferol/vitamin D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which Vitamin D is from sunshine?

A

D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which Vitamin D is from the diet?

A

D2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is active vitamin D formed?

A

UVB
7-dehydrocholestrol
Pre-vitamin D
Vitamin D3

25-hydroxylase
25(OH)cholecalciferol

1 alpha-hydroxylase
1,25(OH)2 cholecalciferol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is 25-hydroxylase located?

A

Liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is 1 alpha-hydroxylase located?

A

Kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is active Vitamin D called?

A

Calcitriol

1,25(OH)2 cholecalciferol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the effects of calcitriol?

A
  1. Increased osteoblast activity
  2. Increased calcium and phosphate absorption in the kidney
  3. Increased calcium and phosphate absorption in the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the actions of PTH?

A
  1. Increased calcium resorption from bone
  2. Increased calcium reabsorption, and phosphate excretion in the kidney
  3. Increased 1 alpha-hydroxylase activity in the kidney
    => Increased 1,25(OH)2D3 synthesis
    => Increased calcium and phosphate absorption in the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What inhibits the sodium/phosphate co-transporter?

A
  1. PTH

2. FGF23

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does FGF23 do?

A
  1. Inhibits sodium/phosphate co-transporter
    => Phosphate lost in urine, not reasbsorbed
  2. Inhibits calcitriol formation
    => Less phosphate reabsorption from gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the symptoms of hypocalcaemia?

A
  1. Paraesthesia (hands, mouth, feet , lips)
  2. Convulsions
  3. Arrhythmias
  4. Tetany
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the signsof hypocalcaemia?

A
  1. Chvostek’s sign

2. Trousseau’s sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Chvostek’s sign?

A

Facial paresthesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What sign is facial paresthesia?

A

Chvostek’s sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is Trousseau’s sign?

A

Carpopedal spasm

25
Q

What sign is a carpopedal spasm?

A

Trousseau’s sign

26
Q

What are the causes of hypocalaemia?

A
  1. Low PTH levels - hypoparathyroidism

2. Low vitamin D levels

27
Q

What are causes of hypocalaemia relating to hypoparathyroidism?

A
  1. Surgical – neck surgery
  2. Auto-immune
  3. Magnesium deficiency
  4. Congenital (agenesis, rare)
28
Q

What are causes of hypocalaemia relating to low Vit D levels?

A

Deficiency:

  • Diet
  • UV light
  • Malabsorption
  • Impaired production (renal failure)
29
Q

What are the symptoms of hypercalcaemia?

A
  1. Stones – renal effects
  2. Abdominal moans - GI effects
  3. Psychic groans - CNS effects
30
Q

What are the renal symptoms of hypercalcaemia?

A
  1. Nephrocalcinosis
  2. Kidney stones
  3. Renal colic
31
Q

What are the GI symptoms of hypercalcaemia?

A
  1. Anorexia
  2. Nausea
  3. Dyspepsia
  4. Constipation
  5. Pancreatitis
32
Q

What are the CNS symptoms of hypercalcaemia?

A
  1. Fatigue
  2. Depression
  3. Impaired concentration
  4. Altered mentation
  5. Coma (usually >3mmol/L)
33
Q

What are the causes of hypercalcaemia?

A
  1. Primary hyperparathyroidism
  2. Malignancy
  3. Vitamin D excess (rare)
34
Q

How does primary hyperparathyroidism cause hypercalcaemia?

A

Too much PTH
Usually due to a parathyroid gland adenoma
No negative feedback - high PTH, but high calcium

35
Q

How does malignancy cause hypercalcaemia?

A 
Bony metastases produce local factors to activate osteoclasts
Certain cancers (eg squamous cell carcinomas) secrete PTH-related peptide that acts at PTH receptors
36
Q

What is the relationship between PTH and calcium?

A

Inversely proportional

37
Q

What is primary hyperparathyroidism caused by?

A

Parathyroid adenoma producing too much PTH

38
Q

What happens in primary hyperparathyroidism?

A

Calcium increases, but no negative feedback to PTH due to autonomous PTH secretion from parathyroid adenoma

39
Q

What is the biochemistry of primary hyperparathyroidism?

A
  1. High calcium
  2. Low phosphate – increased renal phosphate excretion (inhibition of Na+/PO43-transporter in kidney)
  3. High PTH (not suppressed by hypercalcaemia)
40
Q

What is the treatment of primary hyperparathyroidism?

A

Parathyroidectomy

41
Q

What are the risks of untreated hyperparathyroidism?

A
  1. Osteoporosis
  2. Renal calculi (stones)
  3. Psychological impact of hypercalcaemia – mental function, mood
42
Q

Is secondary hyperparathyroidism pathological or physiological?

A

Normal physiological response to hypocalaemia

43
Q

What is the biochemistry of seconday hyperparathyroidism?

A
  1. Calcium will be low or low/normal

2. PTH will be high (hyperparathyroidism) secondary to the low calcium

44
Q

What are the causes of secondary hyperparathyroidism?

A

-Most common cause of secondary hyperparathyroidism is vitamin D deficiency

  • Commonly - diet, reduced sunlight
  • Less common, but important = renal failure – can’t make calcitriol in renal failure
45
Q

What does PTH stimulate?

A

Renal 1-alpha-hydroxylase

46
Q

What is the treatment of secondary hyperparathyroidism in patients with normal renal function?

A
  • Give 25 hydroxy vitamin D
  • Patient converts this to 1,25 dihydroxy vitamin D via 1a hydroxylase
  • Ergocalciferol 25 hydroxy vitamin D2
  • Cholecalciferol 25 hydroxy vitamin D3
47
Q

What is the treatment of secondary hyperparathyroidism in patients with renal failure?

A

Give Alfacalcidol - 1a hydroxycholecalciferol

48
Q

Why cannot you give 25 hydroxy vitamin D to treat secondary hyperparathyroidism in patients with renal failure?

A

Inadequate 1a hydroxylation, so can’t activate 25 hydroxy vitamin D preparations

49
Q

When does tertiary hyperparathyroidism occur?

A
  • Chronic renal failure

- Chronic vit D (calcitriol) failure

50
Q

What happens in tertiary hyperparathyroidism?

A
  • Can’t make calcitriol
  • PTH increases (hyperparathyroidism)
  • Parathyroid glands enlarge (hyperplasia)
  • Autonomous PTH secretion causes hypercalcaemia
51
Q

What is the treatment for tertiary hyperparathryoidism?

A

Parathyroidectomy

52
Q

What is the diagnostic approach to hypercalaemia?

A

Always look at the PTH

53
Q

What is the normal PTH response to hypercalaemia?

A

PTH falls

54
Q

What will you see in hypercalaemia due to malignancy?

A

Hypercalaemia

Low/supressed PTH

55
Q

What is the diagnosis if a patient with hypercalaemia has raised PTH?

A

Hyperparathyroidism

56
Q

When is it primary hyperparathyroidism?

A

If renal function is normal

e.g. parathyroid adenoma

57
Q

When is it tertiary hyperparathyroidism?

A

If chronic renal failure

58
Q

What is it called if all 4 glands are enlarged in tertiary hyperparathyroidism?

A

Hyperplastic

59
Q

What is vitamin D measured as?

A

25 (OH) vitamin D

Y2 BRS Endocrinology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions