Chronic Kidney Disease

Question 1

Define chronic kidney disease

Answer 1

Abnormalities of kidney structure of function, present for >3 months, with kidney damage (abnormalities or markers of damage including those in blood or urine tests or imaging) or GFR

Question 2

What are the stages of CKD

Answer 2

1: normal, structural abnormality/persistent haematuria or proteinuria (GFR >90l/min per 1.73m^2)
2: mildly reduced function, asymptomatic (GFR 60-89ml/min per 1.73m^2)
3: Mod. reduced function, renal osteodystrophy (GFR <15ml/min per 30-59m^2)
4: Severe reduced function, metabolic derangement, anaemia (GFR 15-29ml/min per 1.73m^2)
5: End stage renal failure (GFR <15ml/min per 1.73m^2)

Note: Stage 5 renal failure is much less common in children than in adults

Question 3

What are the causes of chronic kidney disease

Answer 3

Congenital/inherited: PKD, Alport’s syndrome, congenital hyperplasia
Renal dysplasia ± reflux
Obstruction: myeloma, HIV nephropathy, scleroderma, gout, renal tumour, inborn errors of metabolism
Glomerular: glomerulonephritis, DM, amyloid, SLE
Congenital nephrotic syndrome
Vascular: HTN, renal artery atheroma, vasculitis
Metabolic

Congenital and familial causes are more common in childhood- e.g. structural malformations and hereditary nephropathies

Question 4

What are the symptoms of chronic kidney disease

Answer 4

Stage 4/5 CKD

Polydipsia and polyuria
Urine: cola-coloured, foamy urine
Faltering growth/ growth failure
Anorexia and lethargy
Nausea ± vomiting
Pruritus
Anaemia: Dyspnoea
Oedema e.g. ankle swelling, weight gain
Restless legs
Arthralgia

Acute-on-chronic renal failure (precipitated by infection or dehydration)

Question 5

What investigations should be done for chronic kidney disease

Answer 5

Bedside:
- Urine dip: proteinuria
- Urinary albumin: mod. increase (used for albumin excretion rate (AER) or albumin: creatinine ratio)

Bloods
- FBC: normochromic, normocytic anaemia (anaemic of chronic disease)
- Renal screen: Raised urea and creatinine, eGFR <60ml/min/1.73m^2
- Calcium: hypocalcaemia (vit D)
- ALP: increased, phosphate and PTH also increased
- BNP: raised
- Blood film: echinocytes or Burr cells (“spiky membrane”)

Other:
- Renal US: small kidneys seen ± obstruction/hydronephrosis, kidney stones
- Renal biopsy
- CXR: ? fluid overload

Question 6

What is the management for CKD

Answer 6

Dietary changes
Prevent renal osteodystrophy
Salt supplements and fluids
Bicarbonate supplements (prevent acidosis)
EPO supplementation (for anaemia due to reduced EPO)
Recombinant human GH (due to GH resistance → poor growth)
Dialysis and transplantation

Question 7

What dietary changes should be recommended for CKD

Answer 7

Calorie supplements ± NG/gastrostomy feeding to optimise growth due to anorexia and vomiting in CKD
Ensure sufficient protein intake

Question 8

How do you prevent osteodystrophy in someone with CKD

Answer 8

Reduce phosphate intake (reduce milk)
Phosphate binders e.g. calcium carbonate, sevelamer
Vit D supplements: alfacalcidol, calcitriol
Consider parathyroidectomy (due to secondary hyperPTH)

Question 9

What are the types of dialysis for CKD

Answer 9

Peritoneal: cycling overnight OR a continuous cycling machine OR manual exchange over 24h (continuous ambulatory)
Haemodialysis: 3-4x per week in hospital

Question 10

What are the complications of CKD

Answer 10

Metabolic acidosis
Water retention: Pulmonary/peripheral oedema, ascites, raised JVP
Hyperkalaemia and check potassium levels every 4 hours
Hyponatraemia
Toxin accumulation e.g. urea
Blood pressure: normal in AKI, raised in CKD
EPO: normal in AKI, raised in CKD
Vitamin D: normal in AKI, reduced in CKD