Chronic Kidney Disease

Question 1

Causes of CKD

Answer 1

Diabetes
Hypertension
Age-related decline
Glomerulonephritis
Polycystic kidney disease
Medications such as NSAIDS, proton pump inhibitors and lithium

Question 2

Presentation of CKD

Answer 2

Pruritus (itching)
Loss of appetite
Nausea
Oedema
Muscle cramps
Peripheral neuropathy
Pallor
Hypertension

Question 3

Investigating CKD

Answer 3

Investigations
Estimated glomerular filtration rate (eGFR) can be checked using a U&E blood test. Two tests are required 3 months apart to confirm a diagnosis of chronic kidney disease.

Proteinuria can be checked using a urine albumin:creatinine ratio (ACR). A result of ≥ 3mg/mmol is significant.

Haematuria can be checked using a urine dipstick. A significant result is 1+ of blood. Haematuria should prompt investigation for malignancy (i.e. bladder cancer).

Renal ultrasound can be used to investigate patients with accelerated CKD, haematuria, family history of polycystic kidney disease or evidence of obstruction.

Stages
The G score is based on the eGFR:

G1 = eGFR >90
G2 = eGFR 60-89
G3a = eGFR 45-59
G3b = eGFR 30-44
G4 = eGFR 15-29
G5 = eGFR <15 (known as “end-stage renal failure”)
The A score is based on the albumin:creatinine ratio:

A1 = < 3mg/mmol
A2 = 3 – 30mg/mmol
A3 = > 30mg/mmol
The patient does not have CKD if they have a score of A1 combined with G1 or G2. They need at least an eGFR of < 60 or proteinuria for a diagnosis of CKD.

Question 4

Complications of CKD

Answer 4

Anaemia
Renal bone disease
Cardiovascular disease
Peripheral neuropathy
Dialysis related problems

Question 5

Treating CKD

Answer 5

Slowing the progression of the disease

Optimise diabetic control
Optimise hypertensive control
Treat glomerulonephritis

Reducing the risk of complications

Exercise, maintain a healthy weight and stop smoking
Special dietary advice about phosphate, sodium, potassium and water intake
Offer atorvastatin 20mg for primary prevention of cardiovascular disease

Treating complications

Oral sodium bicarbonate to treat metabolic acidosis
Iron supplementation and erythropoietin to treat anaemia
Vitamin D to treat renal bone disease
Dialysis in end stage renal failure
Renal transplant in end stage renal failure

Question 6

Treating Hypertension in CKD

Answer 6

ACE inhibitors are the first line in patients with chronic kidney disease. These are offered to all patients with:

Diabetes plus ACR > 3mg/mmol
Hypertension plus ACR > 30mg/mmol
All patients with ACR > 70mg/mmol
Aim to keep blood pressure <140/90 (or < 130/80 if ACR > 70mg/mmol).

Serum potassium needs to be monitored as chronic kidney disease and ACE inhibitors both cause hyperkalaemia.

Question 7

Anaemia of CKD

Answer 7

Healthy kidney cells produced erythropoietin. Erythropoietin is the hormone that stimulates production of red blood cells. Damaged kidney cells in CKD cause a drop in erythropoietin. Therefore there is a drop in red blood cells and a subsequent anaemia.

Anaemia can be treated with erythropoiesis stimulating agents such as exogenous erythropoeitin. Blood transfusions should be limited as they can sensitise the immune system (“allosensitisation”) so that transplanted organs are more likely to be rejected.

Iron deficiency should be treated before offering erythropoetin. Intravenous iron is usually given, particularly in dialysis patients. Oral iron is an alternative.