Lecture: Calcium Flashcards

1
Q

Functions of calcium in the body (8)

A
Structural role
Activator 
Blood caogulation
Skeletal and cardiac muscle contraction 
Nerve impulse transmission 
Milk production
Regulation of membrane ion transport
Cellular secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Major sources of dietary calcium

A

Milk and milk products

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

Factors affecting the variability in absorption of calcium from the SI

A
Concentration in the diet
pH
Presence of activated vitamin D
Parathyroid hormone
High protein Diet
Steatorrhea
Age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Storage of calcium in the body

A

Gut
ECF
Kidney
Bone (highest conc)

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

What 3 forms is calcium present in serum in

A

Ionised/free (active)
Complexed
Protein bound (inactive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are blood calcium levels influenced by

A

Parathyroid hormone
Calcitonin
Vitamin D

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

How many amino acids compose the PTH

A

84

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

When is PTH released

A

When ECF calcium is decreased

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

What organs/tissues does PTH act on

A

Bone, kidney and intestine

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

Describe calcitonin molecule

A

32 amino acid peptide with one disulphide bond

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

What secretes calcitonin

A

C cells of the thyroid in response to an increase in ionised calcium

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

Three target tissues for activated vitamin D

A

Intestine, bone and kidney

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

How much calcium is bound to albumin

A

50%

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

Non diseases state total serum calcium level

A

2.4 mmol/L

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

When is binding of calcium to protein decreased/increased

A

Decreased in acidosis states

Increased in alkalosis states

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

What is normal calcium level required for

A

Nerve function, membrane permeability and glandular secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Does PTH glands recognise unbound or bound calcium

A

Unbound

18
Q

Why is “adjusted calcium used”

A

So patients with low albumin are not mistaken for being hypocalcaemic
and so
patients with normal calcium low albumin are not missed for being hypercalaemic

19
Q

How to calculate adjusted calcium (mmol/L)

A

Total calcium + 0.02(47-[albumin])

20
Q

Causes of hypocalcaemia

A

Hypoparathyroidism
Vitamin D deficiency
Renal disease
Pseudohypoparathyroidism

21
Q

Clinical features of hypocalcaemia

A

Neurological features such as tingling, tetany and mental changes, cardiovascular signs and cataracts

22
Q

What should adjusted calcium level be

A

above 2.1 mmol/L

23
Q

What further tests should be done following measuring Ca and albumin to determine if patient is hypocalcaemic

A

Measure urea and creatinine for renal disease.

Check PTH is appropriate to serum Ca.

24
Q

Treatment for hypocalcaemia

A

Oral calcium supplements

25
Q

Causes of hypercalcaemia

A

Primary hyperparathyroidism and hypercalcaemia of malignancy

26
Q

Clinical features of hypercalcaemia

A

Neurological and psychiatric features such as lethargy, confusion
Irritability and depression
Gastrointestinal problems such as anorexia, abdominal pain, renal features such as thirst and polyuria
Cardiac arrhytmias

27
Q

What does a level of 3.5 mmol/L or greater of adjusted calcium mean

A

Life threatening and action is required immediately

28
Q

Treatment of hypercalcaemia

A

Intravenous saline is administered to restore GFR and promote a diuresis

Aminohydroxypropylidene diphosphate is treatment of choice in patients with hypercalcemia of malignancy. (inhibits bone reabsorption)

29
Q

Average dietary intake of magnesium

A

15 mmol per day

30
Q

When is hypermagnesaemia seen

A

Uncommon but occasionally seen in renal failure

31
Q

Symptoms of hypomagnesaemia

A

Impaired muscle function such as tetany, hyperirritability, tremor, convulsions and muscle weakness

32
Q

Laboratory diagnosis of hypomagnesaemia

A

Spectrophotometric with metallochromic indicators, calmagite and methylthymol blue, formazan dye, magon and phosphoazo III

33
Q

At what level of magnesium conc. might benefit from magnesium therapy

A

< 0.7 mmol/L

34
Q

How to detect intracellular magnesium concentration when Mg is within reference range

A

Research procedure NMRspectro-scopy to detect free MG 2+ inside cells

35
Q

What can magnesium supplements cause

A

Diarrhoea

36
Q

What is phosphate attached to

A

Inside cells mostly attached to lipids and proteins

37
Q

Where is most of the bodys phosphate

A

In bone

38
Q

How is control of ECF phosphate concentration achieved

A

By the kidney where tubular reabsorption is reduced by PTH

39
Q

Normal phosphate concentration (monohydrogen phosphate and dihydrogen phosphate)

A

0.8 -1.4 mmol/L

40
Q

Causes of hyperphosphateaemia

A

Renal failure
Hypoparathyroidism
Haemolysis
Pseudohypoparathyroidism

41
Q

Causes of hypophosphataemia

A
Hyperparathyroidism
Congenital defects of tubular phosphate reabsotpion
Ingestion of non-absorbabke antacids
Treatment of diabetic ketoacidosis 
Sever dietary deficiency.