Chronic Kidney Disease

Question 1

What is the definition of chronic kidney disease?

Answer 1

Kidney damage or an GFR <60ml/min for 3+ months

Question 2

What is creatinine and what is serum creatinine proportional to?

Answer 2

Product of muscle metabolism which is produced at a fairly constant rate.
Serum creatinine is inversely proportional to GFR (also depends on muscle mass)

Question 3

What are some of the problems regarding serum creatinine?

Answer 3

• There is a lag time between loss of renal function and the fall of creatinine.
• The effects of muscle mass can lead to overestimation in women, elderly and other low mass groups.

Question 4

What are the problems with eGFR?

Answer 4

• Not validated in elderly or non-white and non-black patient groups.
• Not valid in AKI or pregnancy

Question 5

What are the classifications of chronic kidney disease?

Answer 5

Stage 1: eGFR > 90 (with evidence of kidney damage)
Stage 2: eGFR 60-89 (with evidence of kidney damage)
Stage 3a: eGFR 45-59 (mild-moderate decrease in eGFR)
Stage 3b: eGFR 30-44 (moderate-severe decrease in eGFR)
Stage 4: eGFR 15-29 (severe decrease)
Stage 5: eGFR < 15 (established renal failure)
Recently can also use albuminuria to categorise CKD

Question 6

What is the best method of quantifying proteinuria?

Answer 6

• Dipstick can have 1+ in normal pts or in exercise or fever.
• Best method is the urine protein to creatinine ratio as the ratio accounts for changes in hydration

Question 7

What is ACR and PCR?

Answer 7

ACR - albumin creatinine ration.
PCR - Protein creatinine ratio.

Question 8

What are some causes of chronic kidney disease?

Answer 8

• Diabetic nephropathy,
• Hypertension,
• Chronic glomerulonephritis (membranous or IgA)
• Polycystic kidney disease
• Renovascular disease/ischaemic nephropathy,
• Reflux nephropathy (which can lead to chronic pyelonephritis),
• Obstructive uropathy

Question 9

What are the symptoms of CKD?

Answer 9

• Pruritus,
• Nausea, anorexia and weight loss,
• Fatigue,
• Leg swelling (due to loss of water and salt control)
• Breathlessness,
• Nocturia,
• Joint/bone pain,
• Confusion

Question 10

What are the signs of advanced CKD?

Answer 10

• Peripheral and pulmonary oedema,
• Pericardial rub (due to accumulation of toxins in pericardium),
• Rash/excoriation,
• Hypertension,
• Tachypnoea,
• Cachexia,
• Pallor or lemon yellow tinge

Question 11

How can you slow the progression of CKD?

Answer 11

• Aggressive BP control,
• Good diabetic control,
• Diet,
• Smoking cessation,
• Lowering cholesterol,
• Treat acidosis

Question 12

WHat drugs are used for BP control in CKD?

Answer 12

• ACE-i/ARBs. These will cause efferent arteriole dilitation and reduce BP in the glomerulus which will slow further damage to the glomerulus. Once started on ACEi/ARB pts eGFR will fall by 25% in first few weeks but this is good.

Question 13

Explain the management of anaemia in CKD?

Answer 13

• Occurs when eGFR is below 30,
• Treat via iron/B12/folate if low and ESA such as Darbepoietin.
• Aim for Hb 100-120g/l

Question 14

Explain the pathophysiology and management of secondary hyperparathyroidism in CKD

Answer 14

• In CKD, there is reduced activation of vitamin D by the kidneys which reduces the gut absorption of calcium. Hypocalcaemia stimulated PT gland to secrete excessive PTH. This can cause bone disease
• Treatment is via supplementation with active vitamin D (Alfacalcidol), phosphate binders (reduce phosphate) or give Cinacalcet

Question 15

What are the different options for renal replacement therapy?

Answer 15

• Transplant,
• Home haemodialysis or PD,
• Hospital haemodialysis

Question 16

When should dialysis be started?

Answer 16

• Individual approach based on symptoms. However most start when eGFR is 6-8ml/min.