Calcium homeostasis Flashcards Preview

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Flashcards in Calcium homeostasis Deck (26):
1

What factors effect calcium homeostasis?

Dietry intake
Gut absorption
PTH
Vit D

2

How is vitamin D produced in the body?

Dehydrocholesterol (skin, UV)
To cholecalciferol (D3, to liver)
To 25(OH)Vit D (to kidney)
To 1,25 (OH) Vit D (to rest of body)

3

What are the acute/ chronic symptoms of hypercalcaemia?

Acute:
Thirst
Dehydration
Confusion
Polyuria

Chronic:
Myopathy
Osteopaenia
Fractures
Depression
Hypertension
Abdo pain (pancreatitis,ulcers,renal stones)

4

What are the causes of hypercalcaemia?

Primary hyperparathyroidism
Malignancy
Vit D
Thiazides
Hypocalcuric Hypercalcaemia
High turnover (paget's, bedridden, thyrotoxic)
Tertiary hyperparathyroid

5

How is primary hyperparathyroidism diagnosed?

Raised serum Ca2+
Raised serum PTH
Increase urine Ca2+

6

How is malignancy hypercalcaemia diagnosed?

Raised Ca2+ and ALP
Xray, CT, MRI
Isotope bone scan

7

Why do you get hypercalcaemia in malignancy?

Bone mets
PTHrp from solid tumours
osteoclast activating factors

8

How is acute hypercalcaemia treated?

0.9% saline, rehydrate, 4-6L/24hr
Loop diuretic once rehydrated (not thiazide)
Bisphophonates (single dose, max effect 1 week)
Steriods ocasionally (sarcoid)
Chemo (myeloma)

9

How is primary hyperparathyroidism managed?

Surgery or nothing
(not always required)

10

What are the indications for parathyroidectomy?

End organ damage
very high Ca2+ (>2.85)
Under 50yrs
eGFR <60

11

What are the PTH and Ca2+ levels in
a)primary hyperparathyroid
b)secondary hyperparathyroid
c)tertirary hyperparathyroid?

a)PTH up, Ca2+ up
b)Ca2+ low, PTH up
c)Ca up, PTH up (autonomous after years of 2ndary)

12

What is the algorithm when assesing cause of hepercalcaemia?

Raised Ca2+
Albumin
Phosphates
Alk Phosph

13

What is hypocalciuric hypoecalcaemia?

Autosomal DOminant
Usually asymptomatic
mild hyperCa2+
reduced Ca2+ in urine
PTH (marginally) up

14

What are the symptoms of hypercalcaemia?

Paraesthesia

15

What is hypocalciuric hypercalcaemia?

Autosomal DOminant
Usually asymptomatic
mild hyperCa2+
reduced Ca2+ in urine
PTH (marginally) up

16

What are the symptoms of hypocalcaemia?

Paraesthesia (fingers, toes, perioral)
Muscle cramps (tetany)
Muscle weakness
Fatigue
Broncho/laryngospasm
fits
Chovsteks sign
Trousseau sign
QTprolongation

17

What can cause hypocalcaemia?

Hypoparathyroid
Vit D deficiency
CKD
Pancreatitis
Hyperventilation
Osteoblastic bone mets
Rhabdomyolysis

18

What is the treatment for acute hypocalcaemia?

IV calcium gluconate (10ml, 10% over 10 mins)
in 50ml saline or dextrose
Infusion, (10ml, 10% in 100ml at 50ml/hr)

19

What are the causes of hypoparathyroidism?

Congenital absence (diGeorge)
Destruction(surgery, radio)
Autoimmune
Hypomagnesaemia
idiopathic

20

What is the long term management of hypocalcaemia?

Calcium supplement
Vit D tablets (alpha caldidol tablets or cholecalciferol injection)

21

What is pseudohypoparathyridism?

Genetic defect of Gprotein Gs alpha (GNAS1)

22

What are the hormone levels in pseudohypoparathyridism?

Low Ca2+
high PTH

(PTH resistance)

23

What are the signs of pseudohypoparathyridism?

Bone abnormalities
Obesity
Subcut calcification
Mental retardation
4th metacarpal brachdactyly

24

What is pseudo-pseudohypoparathyroidism?

same as pseudo but with normal Ca2+
(patients can become pseudo pseudo)

25

What conditions are caused by Vit D deficiency?

rickets
osteomalacia

26

What can cause Vit D deficiency?

Dietary
Malabsorption
CKD
Lack of sun
Anticonvulsant drugs