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Year 5 Pathology - Week 1 > Path - calcium > Flashcards

Path - calcium Flashcards

1
Q

Where does PTH obtain calcium from when there’s hypocalciemia?

A

Bone
Renal reabsorption via the activation of 1 alpha hydroxylase

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2
Q

What does 1 alpha hydroxylase do?

A

Activate vitamin D -> this also increases gut calcium absorption

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3
Q

PTH is a protein or steroid? What does it do?

A

84 amino acid protein
stimulates 1 alpha hydroxylase
stimulates phosphate excretion in order to maintain calcium phosph balance and stop crystals from increasing in blood (vit D causes phosphate and calcium retention via gut).

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4
Q

What happens to 7 dehydrocholestrol when in the sun?

A

It makes cholecalciferol

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5
Q

What happens to cholecalciferol and where? What is another name for this?

A

VIt D3 - First pass metabolism - 100 percent hydroxylated to 25 hydroxycholecalciferol

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6
Q

What is the plant vitamin vitamin D?

A

Vit D2 - ergocalciferol

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7
Q

1 alpha hydroxylase can also be expressed where else in which condition?

A

Ectopically expressed in the lungs - can cause hypercalcemia in sarcoidosis

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8
Q

What is the product of 1 alpha hydroxylation of 25 cholecalciferol?

A

CALCTRIOL also called 1 25 cholecalciferol

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9
Q

Who do you prescribe calcitriol to?

A

ONLY to renal patients who can’t 1 alpha 25 hydroxylase

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10
Q

What does calcitriol do?

A

Increases calcium and phosphate absorption from gut

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11
Q

Where is alk phosph released?

A

Liver and bones

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12
Q

When is alk phosph released from bones?

A

When there is bone formation

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13
Q

Define osteomalacia

A

Defective bone mineralisation

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14
Q

Clinical features of osteomalaica/rickets on xrays

A

Looser’s zone fractures

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15
Q

Biochemical features of osteomalacia

A

Low calc
Low phosph
Raised ALP as the bone is trying to heal

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16
Q

Signs of rickets

A

Bowed legs
Costrochondral swelling
widened epiphyses at the wrists
Myopathy

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17
Q

What else can cause rickets?

A

Anticonvulsants

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18
Q

Risk factors for osteomalacia

A

Phytic acid chelates vit D
Renal failure
Lack of sunlight

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19
Q

Define osteoporosis

A

Slow loss of bone mass, causing bone mineral density

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20
Q

Biochemical features of osteoporosis

A

Normal calcium
Normal phosph
Normal alk phosph

21
Q

What is the first feature of osteoporosis?

A

Neck of femur fracture, colles, vertebral fracture

22
Q

Where do you do a DEXA scan?

A

Hip
Spine
Wrist

23
Q

What are the scores for DEXA and what do they mean?

A

Compare with someone who is young - T score

Z score - SD from mean of aged-matched control

24
Q

What do you call it when your bone isn’t as strong as it should be for your age?

A

Failure to attain peak bone mass

25
Q

Causes of osteoporosis

A

Early menopause

26
Q

LIfestyle causes of osteoporosis

A

sedentary
EtOH
smoking
Low BMI/poor diet

27
Q

Endo causes of osteoporosis

A

Hyperprolactinomia
Thyrotoxicosis
CUshings

28
Q

LIfestyle interventions for osteoporosis

A

Weight bearing exercise
Stop smoking
Reduce eTOH

29
Q

Give an example of

A

Alendronate - has nitrogen and phosphate, and nitrogen isn’t biodegradable so osteoclasts have a hard time breaking it down, so it’s really strong

It needs to be taken by itself because it will become inactivated if taken with calcium, e.g. milk
Therefore needs to be taken once a week with a glass of water

Also, it irritates their stomach so

30
Q

ALternative

A

IV Xolandronate - once every year

31
Q

Give an example of a PTH derivative used for osteoporosis

A

Teriparatide

32
Q

Strontium

A

Calcium

33
Q

Give example of oestrogen targeting drugs for osteoporosis

A

Selective estrogen receptor modulator - raloxifene or tamoxifen (antagonistic oestrogen in breast, agonist in bone, has opposite effects - increases bone density and prevents breast cancer)

34
Q

SE of osteoporosis

A

Worsen the symptoms of menopause

35
Q

NORMAL calcium levels

A

2.2 to 2.6 millimoles per litre (mmol/L)

36
Q

How much of bone is calcified?

A

two thirds of bone is calcified

37
Q

Hypercalcemia symptoms

A

Polyuria/polydipsia
Constipation

38
Q

If calcium is high and PTH is normal, what’s the diagnosis?

A

Parathyroid problem - PTH should be undetectable if calcium is high

39
Q

If there’s hypercalcemia, what do you have to check?

A

PTH - is it suppressed?

40
Q

Causes of primary hyperparathyroidism

A

Parathyroid adenoma
Hyperplasia or carcinoma
MEN 1 syndrome

41
Q

3 ways in which hypercalcemia is created by malignancy

A

PTHrp - kidney, breast cancer
Bone mets osetolysis
Haematological malignancies - Cytokines

42
Q

TREATMENT for acute hypercalcemia

A

Normal saline

4 L of normal saline daily, until the calcium lowers

43
Q

If the patient has hypercalcemia of malignancy, what do you give?

A

BISPHOSPHONATES

always avoid bisphosphonates unless you know for sure they have cancer, as otherwise it will drop the calcium levels when you have parathyroid surgery

44
Q

Signs of hypocalcemia

A

Chvostek’s sign
Trousseau’s sign
Hyperreflexia
Seizure - at this point we’ve missed the boat :(
Laryngeal spasm - can cause death

45
Q

Explain Trousseu’s sign

A

Take BP - bp cuff causes
Albumin rises
binds to free calcium
therefore muscles become active and patients get carpal spasm

46
Q

Define Paget’s

A

Focal disorder of bone remodelling

47
Q

Signs of paget’s

A

Focal pain
Warmth
Deformity
Fracture
SC compression
Malignancy
Cardiac failure as more blood is going through that bone

48
Q

Biochemical results for paget’s

A

Elevated alk phosph, everything else is normal

49
Q

Rank higherst to lowest calcium

A

Breast cancer - highest
Primary hyperparathyroidism
Osteoporosis/pagets - normal calcium
Osteomalacia/secondary hypoerparathyroidism

Year 5 Pathology - Week 1 (26 decks)

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