Chronic Kidney Disease

Question 1

What is the relationship between kidney function and serum creatinine?

Answer 1

• Serum creatinine correlates negatively with kidney function.
• The relationship is non-linear.

Question 2

What is the difference between using creatinine clearance and inulin clearance to assess kidney function?

Answer 2

• Both assess glomerular filtration rate.
• However, inulin clearance is more accurate because a small amount of creatinine is reabsorbed, whereas no inulin is reabsorbed.

Question 3

Define chronic kidney disease.

Answer 3

• An eGFR of <60ml/minute/1.73m^2.

or

• Markers of kidney damage present for >3 months.

Question 4

List the stages of chronic kidney disease.

Give the eGFR threshold for each stage.

What are the units for eGFR?

Answer 4

1 - Stage 1 - eGFR >= 90 (eGFR normal but kidney damage present).

2 - Stage 2 - eGFR 60 - 90.

3 - Stage 3 - eGFR 30 - 60.

4 - Stage 4 - eGFR 15 - 30.

5 - Stage 5 - eGFR <15.

• eGFR units: ml/minute/1.73m^2

Question 5

List 9 risk factors for chronic kidney disease.

Answer 5

• Systemic diseases:

1 - Diabetes.

2 - Hypertension.

• Immune-mediated diseases:

3 - Membranous nephropathy.

4 - IgA nephropathy.

• Infectious diseases:

5 - HIV.

6 - Hepatitis.

• Genetic diseases:

7 - Polycystic kidney disease.

• Arterial diseases:

8 - Atherosclerosis.

• Obstruction:

9 - Kidney stones.

Question 6

Give an example of a genetic cause of chronic kidney disease.

Answer 6

Polycystic kidney disease.

Question 7

Describe the pathophysiology of diabetic nephropathy.

Answer 7

• Thickening of the basement membrane.
• Mesangial expansion due to hyperglycaemia stimulating increased matrix production by mesangial cells. Indicated by TGF-beta release.
• Glomerulosclerosis due to intraglomerular ion or ischaemic damage.

Question 8

List 4 causes of obstruction in the urinary tract.

Answer 8

1 - Stones.

2 - Benign prostate.

3 - Tumours.

4 - Fibrosis.

Question 9

Why might chronic kidney disease cause immune suppression?

Answer 9

Due to the buildup of nitrogen waste products in the blood.

Question 10

List 4 treatment and management options for fluid overload due to chronic kidney disease.

Answer 10

1 - Diuretics.

2 - Reduce water intake.

3 - Reduce salt intake.

4 - Dialysis.

Question 11

List 2 treatment and management options for preventing hypernatraemia and hyperkalaemia due to chronic kidney disease.

Answer 11

1 - Reduce salt intake.

2 - Dialysis.

Question 12

List 3 reasons that explain why chronic kidney disease might cause metabolic acidosis.

Answer 12

1 - Impaired ammonia excretion.

2 - Decreased tubular reabsorption of bicarbonate.

3 - Insufficient production of bicarbonate in relation to the amount of acids synthesised in the body and ingested with food.

Question 13

List 2 treatment options for preventing metabolic acidosis due to chronic kidney disease.

Answer 13

1 - Sodium bicarbonate.

2 - Dialysis.

Question 14

What is the role of the kidney in calcium homeostasis?

Give an example of a complication of chronic kidney disease in the context of calcium homeostasis.

Answer 14

• When Ca2+-sensing receptors in the parathyroid gland sense a low blood concentration of Ca2+, the parathyroid gland is stimulated to increase release of parathyroid hormone.
• Parathyroid hormone stimulates the kidney to convert 25 hydroxyvitamin D to its active form, 1,25 dihydroxyvitamin D.
• The active form of vitamin D increases intestinal Ca2+ absorption.
• If the kidney is unable to produce active vitamin D, hyperparathyroidism and hyperphosphataemia will occur.

Question 15

List 3 signs of hyperparathyroidism and hyperphosphataemia.

Answer 15

1 - Arterial calcification.

2 - Soft tissue calcification.

3 - Brown tumours (bone lesions due to osteoclast activity).

Question 16

List 5 treatment and management options for preventing bone diseases and ectopic calcification due to chronic kidney disease.

Answer 16

1 - 1-alpha-hydroxylated vitamin D replacement (an active form of vitamin D).

2 - Reduce phosphate intake.

3 - Phosphate binders.

4 - Calcimimetics.

5 - Parathyroidectomy.

Question 17

What is the treatment for anaemia due to chronic kidney disease?

Answer 17

Recombinant erythropoietin.

Question 18

List 5 mechanisms by which chronic kidney disease can cause hypertension.

Answer 18

1 - Sodium retention.

2 - Volume expansion.

3 - RAAS activation.

4 - Increased sympathetic activity.

5 - Endothelial dysfunction.

Question 19

List 4 treatment and management options for hypertension due to chronic kidney disease.

Answer 19

1 - Reduce salt intake.

2 - Diuretics.

3 - RAAS blockade.

4 - Other antihypertensive medication.

Question 20

List 4 waste products that accumulate in the blood as a result of chronic kidney disease.

Answer 20

1 - Creatinine (after significant renal damage).

2 - Nitrogenous waste.

3 - Urate.

4 - Phosphate.

Question 21

What is the treatment for uraemia due to chronic kidney disease?

Why is protein restriction not a viable option?

Answer 21

• Dialysis.

- Protein restriction is not a viable option because it will cause malnutrition.

Question 22

List 5 examples of drugs that can accumulate in the body due to a reduced ability of the kidney to excrete the drugs as a result of chronic kidney disease.

Give an example of a condition that will result from the accumulation of each drug.

Answer 22

1 - Insulin accumulation leading to hypoglycaemia.

2 - Opiate accumulation leading to narcosis.

3 - Antibiotic accumulation leading to encephalopathy.

4 - Sedative accumulation leading to respiratory arrest.

5 - Digoxin accumulation leading to cardiac arrhythmia.

Question 23

How is drug accumulation due to chronic kidney disease managed?

Answer 23

By modifying the prescription according to renal function.

Question 24

List 10 complications of chronic kidney disease.

Answer 24

1 - Anaemia.

2 - Hypertension.

3 - Disturbed calcium / phosphate homeostasis.

4 - Cardiovascular disease.

5 - Bone diseases.

6 - Abnormal handling of drugs.

7 - Immune suppression.

8 - Increased tendency to bleed.

9 - Oedema.

10 - Dilutional hyponatraemia.