Chronic Kidney Disease (CKD)

Question 1

When should chronic kidney disease (CKD) be suspected in children?

Answer 1

CKD should be suspected in any child with:

• Plasma creatinine above the normal range for age
• Bilateral renal defects on antenatal scans
• Bilateral renal defects on incidental scans e.g. for UTI
• A family history of CKD
• Persistent proteinuria
• Previous AKI
• Hypertension

Question 2

What are the clinical features of CKD?

Answer 2

~50% of cases are diagnosed antenatally. Other presentations include:

• UTI
• Decompensation of CKD causing AKI (precipitated by infection or dehydration)
• Polydipsia and polyuria
• Poor nutritional intake and short stature
• Pallor (anaemia), lethargy and nausea
• Bony abnormalities from CKD mineral and bone disorder (CKD-MBD)
• Incidental finding of proteinuria
• Hypertension
• Mild cases are frequently asymptomatic

Question 3

Briefly describe CKD staging

Answer 3

• Stage 1
  
  • >90
  • Renal parenchymal disease present
• Stage 2
  
  • 60–89
  • Usually no symptoms but may develop biochemical abnormalities at the lower end of the GFR range
• Stage 3A
  
  • 45–59
  • Biochemical abnormalities and anaemia and, in addition, may develop poor growth and appetite
• Stage 3B
  
  • 30–44
• Stage 4
  
  • 15–29
  • Symptoms more severe
• Stage 5
  
  • <15 or dialysis
  • Renal replacement therapy will be required

Question 4

At what age does measuring eGFR become accurate?

Answer 4

This staging system does not apply in the first 2y of life when GFR is increasing from intrauterine levels. Plasma creatinine must be compared to age-matched levels.

Question 5

What are the causes of CKD?

Answer 5

• Congenital anomalies of kidney and urinary tract (CAKUT)
• Renal cystic diseases
• Nephrotic syndromes
• Nephronophthisis (isolated or in association with syndromes)
• GNs
• Vascular events
• aHUS
• Renal stone diseases
• Familial nephropathies
• Systemic diseases (SLE, vasculitis)
• Following AKI

Question 6

What are the aims of management of CKD?

Answer 6

• Slow progression of CKD
• Prevent biochemical and haematological derangements
• Maintain normal growth and development
• Preserve the limb vasculature- when possible, avoid use of:
  
  • Antecubital veins, as they will be needed for fistula formation
  • Subclavian veins, stenosis precludes creation of a fistula in that arm

Question 7

What parameters need to be assessed in outpatient clinics for those with CKD?

Answer 7

• Height, weight and head circumference
• Pubertal stage
• BP

Question 8

Briefly describe the management of growth restriction in CKD

Answer 8

Growth retardation occurs in up to 50% of children with CKD stage 3B-5. Children with congenital nephropathies are particularly affected. Renal transplant can normalise growth in some children. Recombinant human growth hormone (rhGH) is used when all other causes of poor growth are resolved.

Question 9

Briefly describe the management of fluid and electrolyte disturbances in CKD

Answer 9

CKD due to disorders that predominantly affect the RTs (e.g. CAKUT, nephronophthisis) causes salt, HCO₃^– and water wasting. Na⁺ and HCO_3- supplementation and free access to water are necessary.

Glomerular disease (GNs) causes salt and water retention and hypertension may need Na⁺ restriction and diuretics.

A low K⁺ diet may be necessary when GFR <10% normal.

Question 10

Briefly describe the management of anaemia in CKD

Answer 10

PO iron supplements and erythropoiesis-stimulating agents are usually needed when the GFR falls below 30mL/min/1.73m².

Question 11

Briefly describe the management of chronic kidney disease mineral bone disease (CKD-MBD) in CKD

Answer 11

CKD leads to abnormal vitamin D, Ca²⁺, PO₄^3–, fibroblast growth factor 23 (FGF23) and PTH metabolism. Nutritional vitamin D intake and blood levels are low and supplements are needed. As CKD progresses, activated vitamin D needs replacing as well. PO₄^3– clearance decreases and absorption is restricted by using phosphate binders. Stimulation of PTH, alongside high PO₄^3– levels, results in renal bone disease and cardiovascular disease, which is a major cause of death.

Question 12

What may dialysis be considered in children with CKD?

Answer 12

Children should prepare for a living- or deceased-donor transplant once GFR is <15mL/min/1.73m², and it is clear that they are likely to require dialysis in the near future and/or are experiencing significant complications of their CKD.

Question 13

Why is it preferable to avoid dialysis in children?

Answer 13

It is preferable to avoid dialysis because:

• Dialysis is disruptive to family lifestyle, schooling, and social interactions and places huge demands on the family
• Dietary and fluid restrictions are necessary on dialysis
• Mortality is higher on dialysis than post-transplant
• Avoidance of dialysis preserves vascular and peritoneal access sites for future use
• Dialysis is associated with vascular calcification and risk of cardiovascular events
• Well-being, growth and development are improved post-transplant

Question 14

Briefly differentiate between peritoneal dialysis and haemodialysis

Answer 14

• Peritoneal dialysis (PD)
  
  • The commonest choice is continuous cycling automated peritoneal dialysis (CCPD) in the patient’s home (with mobile machines)
• Haemodialysis (HD)
  
  • Vascular access using an arteriovenous fistula (wrist or elbow) is preferable because of ↓ infection risk and better vessel preservation but many children are dialysed through a tunnelled central line
  • The session is usually for 4h, three times per week, in hospital
  • Home HD is possible if there is a family member to support this