4.5: Chronic Kidney Disease

Question 1

Definition of Chronic Kidney Disease?

Answer 1

Reduced GFR and evidence of kidney disease

This must be shown to be chronic (more than one measurement of GFR or creatinine)

Question 2

How is GFR assessed?

Answer 2

Can be assessed in nuclear medicine (radioactive tracer) - time consuming and expensive

Can be monitored using Creatine clearance (overestimates GFR as is secreted by tubules)

Requirs 24 hour urine collection

Can be estimated from serum creatinine, age, race and sex (eGFR)

Question 3

What is creatinine produced from?

Who has more of this?

Answer 3

Product of muscle breakdown

Higher levels in more muscular people (Eg: Young, black men)

Question 4

Who is eGFR less accurate in?

Answer 4

Someone with a very low muscle mass (Eg: Thin, wasted people, those with amputations) - OVER ESTIMATED GFR

Those who have very high muscle mass - UNDER ESTIMATE GFR

Those who have unstable creatinine

Question 5

Describe stage 1 of CKD?

Answer 5

GFR >90

With evidence of kidney damage

(Eg: Haematuria, Proteinuria, Abnormal Imaging)

THIS IS MILD CKD

Question 6

Describe stage 2 of CKD?

Answer 6

GFR 60-90ml/min

Evidence of kidney damage

(Eg: Proteinuria, haematuria, abnormal imaging)

MILD CKD

Question 7

Describe stage 3 of CKD?

Answer 7

GFR = 30-60ml/min

No need for evidence of kidney damage

MODERATE

Question 8

Describe stage 4 of CKD?

Answer 8

GFR = 15-29ml/min

No need for evidence of kidney disease

MODERATE CKD

Question 9

Describe stage 5 of CKD?

Answer 9

GFR <15ml/min

OR DIALYSIS is required

SEVERE CKD

Question 10

How common is CKD?

Answer 10

Mild (1 and 2) is fairly common = 7% of population

Stage 5 = 0.1% (much less common)

Question 11

Why is identifying early CKD (1-3) important?

Answer 11

Early, mild CKD can progress to late stage

Most won’t progress and need dialysis/replacement

However important to recognise those who may progress and need dialysis

ALSO

Mild CKD increases cardiovascular risk

Question 12

Which patients are more likely to progress from mild to severe CKD?

Answer 12

Those with proteinuria (the higher the proteinuria, the faster the progression)

Younger patients (more likely to reach stage 5)

Question 13

Common causes of CKD?

Answer 13

Diabetes

Hypertension

Vascular Disease

Chronic Glomerulonephritis

Reflux Nephropathy

Polycystic Kidneys

Cause not always known

Question 14

Most common cause of end stage renal failure and need for dialysis?

Answer 14

Diabetes

Question 15

Symptoms of CKD?

Answer 15

Symptoms don’t occur until late (GFR <20ml/min)

Non specific - tiredness, poor appetite, itch, sleep disturbance

Impaired urinary concentration - nocturia, frequency,

Question 16

Management of CKD?

Answer 16

• Slow progression of CKD
• Reduce CVS risk
• Identify and treat complications
• Prepare for renal replacement therapy

Question 17

How do you slow progression of CKD?

Pharmacological treatments?

Caution?

Answer 17

Treat proteinuria (slows progression)

Control BP

Stop Smoking

Diabetic Control

ACE Inhibitors and ARBs reduce proteinuria and reduce BP

Also evidence for Spironlactone

Slight fall in GFR when you start ACE inhibitors, hyperkalaemia

Question 18

How do you reduce cardiovascular risk?

Answer 18

Control BP

Reduce proteinuria

Stop Smoking

Statins (for cholesterol)

Question 19

Describe how CKD causes anaemia?

Investigation?

Answer 19

Kidneys produce erythropoeitein

Production declines in CKD

Can cause anaemia

Check iron status, B12 and folate levels

Question 20

How do you treat anaemia in advanced CKD?

Answer 20

• IV Iron
• Erythropoeitein Injection (Epo)

Question 21

Describe how CKD causes bone disease?

Answer 21

Vitamin D is hydroxylated in the kidney

This is impaired in CKD

Leads to reduce calcium absorption leading to secondary hyperparathyroidism

Also in advanced CKD, serum phosphate rises which increases PTH secretion

A normal serum calcium can be maintained by releasing calcium from the bones

Question 22

Describe what happens when you have CKD and develop secondary hyperparathyroidism?

Answer 22

Hyperplasia of all parathyroid glands

Can cause teritary hyperparathyroidism (PTH secretion not suppressed by calcium)

Question 23

Describe the affect of CKD on blood vessels?

Answer 23

Causes calcifiation and stiffness of the vessels

Also calcification of heart valves

Contributes to cardiovascular risk

Question 24

Management of bone disease in CKD?

Answer 24

Alfacacidol - hydroxylated form of Vitamin D that doesn’t need activated in the kidneys

Phosphate advance from dieticians

Phosphate binders (Bind to phosphate in gut to prevent absorption)

Question 25

What are the types of Renal Replacement Therapy?

Answer 25

• Dialysis (Haemodialysis or Peritoneal Dialysis)
• Transplantation
• Conservative Management

Question 26

Describe Arteriovenous Fistula?

Answer 26

Placed 6 weeks prior to starting dialysis

Patients referred to vascular surgeons when GFR reaches about 15ml/min

Question 27

Describe how you get access for peritoneal dialysis?

Answer 27

Operation needed to insert catheter

This happens about 1-2 weeks before dialysis begins

Question 28

When can patients be listed for transplant?

Answer 28

When they are within 6 months of dialysis

They must be fit enough for the transplant (At least 5 year survival)

Question 29

Describe conservative management for severe CKD?

Answer 29

Often chosen by older patients with many co-morbidities

Choose not to have dialysis, not suitable for transplant

Still choose other care - Epo, symptom control