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Tim CP3 @ UoN - Medicine & Surgery > Hypercalcaemia/Parathyroid Disease > Flashcards

Hypercalcaemia/Parathyroid Disease Flashcards

1
Q

How much of plasma calcium is bound to albumin?

A

40% (inactive)

Non-bound is ionized

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2
Q

What effect do acidotic states have on ionized calcium level?

A

Increase ionized calcium level by decreasing protein binding

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3
Q

What effect do alkalotic states have on ionized calcium level?

A

Decrease ionized calcium level by increasing protein binding

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4
Q

What are the main factors controlling plasma calcium level?

A

PTH
Vit D
Calcitonin

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5
Q

Where is PTH produced?

A

Chief cells in parathyroid glands

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6
Q

When is PTH secreted?

A

Low plasma calcium
Low Vit D
High phosphate

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7
Q

What are the effects of PTH?

A

Raises plasma calcium
-stimulates cal reabsorption from bone
-increases renal tubular cal reabsorption
-stimulates increased GI cal absorption (indirect)
Increases renal phosphate excretion

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8
Q

Where is Vitamin D produced?

A

Synthesised in skin (D3 cholecalciferol)

Ingested (D2 ergocalciferol) –> hydroxylated in liver to 25-OH-D2/3 –> hydroxylated in kidney to active Vit D

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9
Q

What are the effects of Vitamin D?

A

Increases absorption of calcium & phosphate from GI tract
Required for normal bone formation

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10
Q

What are the causes of Vitamin D deficiency?

A

Inadequate sunlight exposure (rickets)
Malabsorptive conditions
Liver/kidney disease

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11
Q

Where is Calcitonin produced?

A

Parafollicular C cells of thyroid gland

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12
Q

When is Calcitonin secreted?

A

Increased plasma calcium

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13
Q

What are the effects of Calcitonin?

A

Decreases plasma calcium by antagonising the effect of PTH on bone

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14
Q

What determines intestinal uptake of calcium?

A

Ionized calcium levels in lumen

Presence of activated Vit D

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15
Q

What determines renal excretion of calcium?

A

Na reabsorption in proximal tubule (90%)

PTH regulation in distal tubule (10%)

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16
Q

What is hypercalcaemia?

A

Plasma calcium >2.5mmol/L

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17
Q

What is the most common cause of hypercalcaemia?

A

1o hyperparathyroidism/malignancy (97%)

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18
Q

What are the causes of excessive PTH secretion, leading to hypercalcaemia?

A

1o hyperparathyroidism
3o hyperparathyroidism
Ectopic PTH secretion (v. rare)

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19
Q

What are the malignant causes of hypercalcaemia?

A

Myeloma
Metastatic deposits in bone
Paraneoplastic (SCC)

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20
Q

What are the causes of excess Vit D, leading to hypercalcaemia?

A

Exogenous excess
Granulomatous disease (TB, sarcoid)
Lymphoma

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21
Q

What are the causes of excess calcium, leading to hypercalcaemia?

A

Milk-alkali syndrome

-antacids increase absorption of calcium

22
Q

What are the other endocrine causes of hypercalcaemia?

A

Thyrotoxicosis

Addison’s

23
Q

What are the renal causes of hypercalcaemia?

A

Severe AKI

24
Q

What are the iatrogenic causes of hypercalcaemia?

A

Thiazide diuretics

Lithium

25
Q

What are the hereditary causes of hypercalcaemia?

A

Familial hypocalciuric hypercalcaemia

26
Q

What is the cause of 1o hyperparathyroidism?

A

Single parathyroid adenomas (80%)

Diffuse glandular hyperplasia (20%) - MEN IIa/IIb

27
Q

How can PTH levels distinguish b/w hyperparathyroidism & malignancy?

A

High in hyperparathyroidism

Low in malignancy

28
Q

What are the PTH/calcium levels like in 1o hyperparathyroidism?

A

PTH high

Calcium high

29
Q

How is 1o hyperparathyroidism managed?

A

Parathyroidectomy

30
Q

What is the major complication of parathyroidectomy?

A

Post-op hypocalcaemia

Give adcal for 14/7

31
Q

What is 2o hyperparathyroidism?

A

Physiological hypertrophy of all parathyroid glands, in response to hypocalcaemia

32
Q

In which pts is 2o hyperparathyroidism seen?

A

Renal disease

Vit D deficiency

33
Q

What are the PTH/calcium levels like in 2o hyperparathyroidism?

A

PTH high

Calcium low/normal

34
Q

What is the cause of 3o hyperparathyroidism?

A

Long-standing 2o hyperparathyroidism

Occurs mostly in renal failure

35
Q

What are the PTH/calcium levels like in 3o hyperparathyroidism?

A

PTH high
Calcium high
Phosphate grossly high

36
Q

What is the management of 2o hyperparathyroidism?

A

Address cause of hypocalcaemia

37
Q

What is the management of 3o hyperparathyroidism?

A

Parathyroidectomy

38
Q

How does 1o hyperparathyroidism present?

A

Often asymptomatic

Sx related to hypercalcaemia

39
Q

What are the sx of hypercalcaemia?

A

Bones - bone pain, fractures, muscle weakness
Stones - renal stones, polyuria, AKI/CKD
Groans - abdo pain, vom, const, pancreatitis, GI ulcers
Moans - depression, confusion, tiredness, hypotonicity

40
Q

What investigations are appropriate in suspected 1o hyperparathyroidism?

A 
PTH (raised)
Ca (raised)
PO4 (low)
ALP (raised)
24hr urinary calcium (raised)
DXA scan (assess osteoporosis)
Technetium/USS (localise tumour)
41
Q

How can 1o hyperparathyroidism be distinguished from familial hypocalciuric hypercalcaemia?

A

In FHH low 24hr urinary calcium

Can use spot calcium:creatinine excretion

42
Q

How can 1o hyperparathyroidism be distinguished from 3o hyperparathyroidism?

A 
Clinical presentation
PO4 levels (low/normal in 1o)
43
Q

What syndromes is 1o hyperparathyroidism associated with?

A

Multiple Endocrine Neoplasia

-autosomal dominant

44
Q

What tumours does MEN I produce?

A

Parathyroid hyperplasia/adenoma
Pancreatic endocrine tumours (gastrinoma/insulinoma)
Pituitary adenoma

45
Q

What tumours does MEN IIa produce?

A

Thyroid medullary carcinoma
Adrenal PCC
Parathyroid hyperplasia

46
Q

What tumours does MEN IIb produce?

A

MEN IIa
Mucosal neuromas
Marfanoid appearance
No hyper PTH

47
Q

What is the immediate management of a patient presenting w/ acute hypercalcaemia?

A

If Ca >3.5mmol/L AND sev sx

  • IV fluids (0.9% NaCl, 3-6L/24hrs, diuretics if overloaded)
  • Bisphosphonates (pamidronate, lowers Ca over 2-3/7)
  • Calcitonin (rapidly reduce Ca, short-lived)
  • Dialysis (if renal impairment)
48
Q

What is the non-immediate management of a patient presenting w/ acute hypercalcaemia?

A

Investigate/treat cause of hypercalcaemia

49
Q

When are steroids used in hypercalcaemia?

A

If hypercalcaemia due to myeloma, lymphoma or sarcoid

50
Q

What is the potentially life threatening complication of 1o hyperparathyroidism?

A

Reduced QT interval

Can lead to cardiac arrest

Tim CP3 @ UoN - Medicine & Surgery (136 decks)

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