Chronic Kidney Disease

Question 1

Describe the standard classification of CKD.

HINT: there are 5 stages, but one of them has 2 subcategories!

Answer 1

Stage 1: GFR 90+

Stage 2: GFR 60-89

Stage 3: GFR 30-59
3A: 45+
3B: <45

Stage 4: GFR 15-29

Stage 5: GFR <15 OR on dialysis

Question 2

Describe additional classification of CKD, based on proteinuria. (3)

Answer 2

A1 - none
A2 - mild proteinuria
A3 - heavy proteinuria

Question 3

List 2 complications of CKD.

Answer 3

Anaemia

Abnormal calcium/phosphate metabolism

Question 4

Describe the abnormal calcium/phosphate metabolism in CKD. (5)

Answer 4

1. Phosphate levels INCREASE (bc not peed out), and calcium levels DECREASE (bc not reabsorbed)
2. Increased phosphate/decreased calcium stimulates PTH
3. PTH causes increased bone resorption to increase calcium levels
   a. BUT this also removes phosphate from bones
   b. Therefore calcium levels CORRECTED, but phosphate INCREASES FURTHER
4. Kidneys can’t work despite PTH, therefore even more PTH stimulated
   a. Positive feedback loop created
5. High levels of calcium and phosphate recombine in the arteries
   a. This causes calcification of arteries

Question 5

How would you manage CKD? (9)

HINT: these management options are split into 3 groups.

Answer 5

SLOW PROGRESSION:
BP control
Reduce proteinuria, e.g.
-ACE inhibitors
-ARBs

TREAT CONSEQUENCES:
Adjust drug doses
Treat anaemia
Treat acidosis
Treat hyperkalaemia
Correct abnormal calcium/hosphate metabolism

TREAT END STAGE RENAL FAILURE:
Dialysis
Palliative care

Question 6

What is the target BP in CKD?

Which drugs would you use to achieve this? (3)

Answer 6

130/80

Beta blockers
ACE inhibitors/ARBs
CCBs

Question 7

Which drugs would you use to reduce proteinuria? (2)

Answer 7

ACE inhibitors

ARBs

Question 8

How do ACE inhibitors/ARBs reduce proteinuria? (3)

Answer 8

Reduction of systemic BP
Relaxation of efferent arteriole, therefore decreased intraglomerular pressure
Gradual reduction in glomerular protein permeability

Question 9

Apart from giving drugs, how would you treat hyperkalaemia? (3)

Answer 9

Correct acidosis

Restrict diet, e.g.

• Chips
• Curry
• Coffee

Stop relevant drugs, e.g.

• Potassium sparing diuretics
• ACE inhibitors/ARBs

Question 10

How would you prevent abnormalities in calcium/phosphate metabolism? (2)

Answer 10

Phosphate binder (with meals)

Alfacalcidol (vitamin D)

Question 11

How would you treat abnormalities in calcium/phosphate metabolism? (2)

Answer 11

Cinacalcet (blocks Ca2+ receptor on parathyroid gland)

Parathyroidectomy

Question 12

Which 2 causes of CKD can cause a concentration deficit?

Answer 12

Reflux nephropathy (congenital)
Obstruction