Session 5 - Kalcium and the Cidney (intentional, promise) Flashcards Preview

Semester 3 - Urinary > Session 5 - Kalcium and the Cidney (intentional, promise) > Flashcards

Flashcards in Session 5 - Kalcium and the Cidney (intentional, promise) Deck (48):
1

Give five functions of Calcium

• Muscle contraction
• Inactivation/activation of enzymes
• Nerve conduction
• Exocytosis
• Hormone secretion
• Haemostasis

2

What is the physiologically active from of Ca2+?

• Ionised form

3

Give the three forms in which Ca2+ is found in the body

• Free ionised species
• Protein bound
• Complexed

4

How much of dietary calcium is absorbed?

• 20-40% is absorbed (25mmol)

5

When does calcium absorption increase? (3)

• Growing children
• Pregnancy
• Lactation

6

How much calcium do the kidney filter per day?

• 250mmol

7

How much of the body's calcium reservoir is found in the ECF?

• 1%

8

What chemical is responsible for the absorption of calcium from the gut?

• 1,25 - OH 2D control

9

Where is the majority of calcium reabsorption in the kidney?

• 65% reabsorbed in proximal tubule
• 20-25% recovered in ascending loop of henle
• 10% recovered in DCT under control of PTH

10

What is the standard 24hr urinary calcium excretion?

• <10 mmol

11

How much calcium filtered by kidney per day?

250 mmol

12

Give the actions of PTH

• Increases reabsorption in kidney
• Increases breakdown of bone

Converts calciferol to calcitriol in kidney

13

What is the inactive form of Calcitriol called?

Calciferol

14

What are the actions of calcitriol?

• Increase breakdown of bone
• Increase reabsorption in kidney

Increase absorption of calcium from gut

15

How is vitamin d2 produced?

• By gut

16

How is vitamin d3 produced?

• By skin

17

How does vitamin D become calciferol?

• Hydroxylation in the liver

18

When does calciferol become calcitriol?

• After 2nd hydroxylation

19

How is Calcium release regulated?

• Negative feed back to parathyroid gland
• Gq receptor inhibit PTH release
• Reduce further calcium absorption

20

What are the three major causes of hypercalcaemia?

• Primary hyperparathyroidism
• Haemtological malignancies
• Non-haematological malignancies

21

How do malignancies cause hypercalcaemia?

• PTHrp released
• Does not convert calciferol to calcitriol

22

Give four systems that hypercalcaemia causes symptoms in

• Gastrointestinal
• Cardiovascular
• Renal
• CNS

23

Give four gastrointestinal symptoms of hypercalcaemia

• Anorexia
• Nausea/Vomiting
• Constipation

24

Give three cardiovascular consequences of hypercalcaemia

• Hypertension Shortened QT
• Enhanced sensitivity to digoxin

25

Give three renal consequences of hypercalcaemia

• Polyuria
• Polydipsia
• Nephrocalcinosis

26

Give three cognitive effects of hypercalcaemia on the CNS

• Cognitive difficulties
• Apathy
• depression

27

Outline treatments for hypercalcaemia

General measures
• Hydration - Increase Ca2+ excretion
• Loop diuretics - Increase Ca2+ excretion
Specific measures
• Bisphosphonates - Inhibit breakdown of bone
• Calcitonin - Opposes the action of PTH
Treat underlying condition

28

What percentage of people will develop kidney stones in their life?

• 20% mean
• 5-10% of women

29

What is the most common form of kidney stone?

• 70-80% made of calcium

30

What factors are involved in the formation of kidney stones?

• Low urine volume
• Hypercalcuria

Low urin pH

31

What does the mechanism of stone formation involve?

• Super-saturation of urine with calcium oxalate

32

What does conservative management of kidney stones involve?

• Increasing fluid intake
• Restricting dieatary oxalate and sodium
• Restrict calcium and animal protein

33

What calcium conc do we want to measure in the blood?

• Ionised calcium

34

What are the problems with measuring ionised calcium?

Degrades quickly

35

What hormone is responsible for calcium absorption from the gut?

Calcitriol (a derivative of vitamin D)

36

How is excess vitamin D stored?

• Converted to 24,25 - (OH)2 vitamin D

Inert

37

Why do people with HIV get vitamin D deficiency?

• Anti-retroviral treatment induces liver enzymes to break down vitamin D

38

Where is calcium reabsorbed in the most part?

• PCT - 65%
• TAL - 25%

39

What three things regulate calcium reabsorption in the kidney?

• PTH
• Vitamin D
• Plasma Ca2+ levels

40

What can be used to treat hypercalcaemia that acts on the kidney?

• Loop diuretics which inhibit Ca2+ reabsorption

41

Whyshould thiazide not be used in hypercalcaemia?

• Increases Ca2+ reabsorptio in kidney

42

What percent of men get renal stones?

• 20%

43

What is the main type of renal stone?

• Calcium

44

Give three types of renal stone other than calcium

• Magnesium Ammonium Phosphate
• Urate
• Cystine

45

What is gout?

• Too much alcohol
• Alcohol competes with urate in kidney
• Urate accumulated in tissues

46

Give five promoters of kidney stone formation?

• Urine supersaturation with calcium oxalate
• Low ionic strength
• Low citrate
• Magnesium
• Low pH

47

What is nephrolithiasis?

• Calculi in the kidney

48

What is the classic presentation of kidney stones?

• Loin to groin pain
• Renal colic
• Hydronephrosis