Paediatric Nephrology

Question 1

A child presents with bright red visible haematuria. What is your differential diagnosis?

Answer 1

Causes of non-glomerular haematuria:

• UTI
• trauma to genitals, kidney or urinary tract
• calculi
• hypercalciuria
• malignancy e.g. Wilm’s tumour
• bleeding disorders
• sickle cell disease

Question 2

A child presents with Cola/tea-coloured urine. What is your differential diagnosis?

Answer 2

Causes of glomerular haematuria:

• IgA nephropathy
• post-streptococcal glomerulonephritis
• Henoch-Schonlein purpura
• haemolytic-uraemic syndrome
• Alport syndrome

Question 3

Name the 5 key features of nephritic syndrome.

Answer 3

1. haematuria (Cola-coloured) + RBC casts
2. proteinuria (<3.5 g/day)
3. HTN
4. oliguria (<300 ml/day)
5. AKI

Question 4

Which features differentiate IgA nephropathy from post-streptococcal glomerulonephritis?

Answer 4

IgA nephropathy

• more common in 10-30 year old males
• presents as intermittent visible haematuria 1-2 days following URTI/GII
• bloods: raised serum IgA, normal C3 levels
• biopsy: mesangial IgA complex deposition

Post-streptococcal glomerulonephritis

• more common in 3-12 year olds
• presents as haematuria 1-2 weeks following GAS throat infection or 3-4 weeks following GAS skin infection
• bloods: positive ASO/ADB (anti-Strep Abs), low C3 levels
• biopsy: mesangial IgG/IgM/C3 complex deposition, lumpy-dumpy appearance

Question 5

How would you manage a child presenting with acute glomerulonephritis?

Answer 5

Supportive management e.g. low-Na diet, BP control with ACEi/diuretics
Corticosteroids may be helpful in some cases.

Question 6

Name the diagnostic criteria for Henoch-Schonlein Purpura.

Answer 6

There must be palpable purpuric rash (usually on back of buttocks + legs) + 1 of following:

• diffuse abdominal pain
• arthritis or arthralgia
• renal involvement (demonstrated by quantified proteinuria or haematuria)
• typical histopathology (leukocytoclastic vasculitis or proliferative glomerulonephritis with predominantly IgA depositis)

Question 7

Suggest 3 possible predisposing factors for calculi formation in children.

Answer 7

1. UTI esp. chronic Proteus infection (staghorn calculi)
2. structural anomalies of renal tract e.g. obstructed pelviureteric junction, megaureter
3. metabolic abnormalities e.g. hypercalciuria, raised uric acid levels following chemo

Question 8

How does Proteus UTI predispose to calculi?

Answer 8

Alkalinise the urine by splitting urea to ammonia, predisposing to phosphate stone formation.

Question 9

Name common organisms causing UTI in children.

Answer 9

1. E. coli
2. Klebsiella spp.
3. Proteus
4. Pseudomonas
5. Streptococcus faecalis

Question 10

Which Ix would you perform on a child presenting with a 1st suspected UTI? What features would support your diagnosis?

Answer 10

1. Urine dip: +ve leucocytes, +ve nitrites

2. Urine MC+S: pure growth >10^5 is significant

Question 11

Which Abx would you prescribe a child with:

• lower UTI (<12 yrs)
• lower UTI (>12 yrs)
• pyelonephritis
• pyelonephritis requiring IV Abx

Answer 11

Lower UTI 3 mths-12 yrs: cephalexin for 3 days
Lower UTI 12-17 yrs: nitrofurantoin for 3 days
Pyelonephritis: cephalexin or co-amoxiclav for 10 days
Pyelonephritis requiring IV: IV cefuroxime (switch to oral Abx once apyrexial for 24 hrs)

Question 12

Name the 4 characteristic features of nephrotic syndrome

Answer 12

1. proteinuria >3.5 g/day
2. hypoalbuminaemia <25 g/L
3. oedema
4. hyperlipidaemia

Question 13

name the most common cause of nephrotic syndrome in children

Answer 13

Minimal change disease (85% of NS in children)

Question 14

How would you assess and investigate a child presenting with suspected nephrotic syndrome?

Answer 14

1. Establish extent of oedema + fluid status:
   - height + weight
   - BP
   - assess peripheral perfusion (e.g. CRT)
2. urine
   - urinalysis
   - microscopy + culture
   - Na+
   - protein:creatinine ratio
3. bloods
   - serum albumin
   - U+Es and creatinine
   - C3/4
   - lipid profile
   - Hb

Question 15

how would you manage a patient with nephrotic syndrome?

Answer 15

Admit to hospital.

1. manage fluid balance
   - treat hypovolaemia if present
   - gentle fluid restriction to 800-1000 mL/24 hrs
   - diuretics (furosemide/spironolactone) if very oedematous and no evidence of hypovolaemia
2. steroid therapy: oral prednisolone (daily for 1 month then decrease)
3. other
   - prophylactic penicillin V until oedema-free
   - pneumonocccal vaccination
   - diet - no added salt and healthy

Question 16

what is the rate of relapse in nephrotic syndrome?

Answer 16

• 30% single relapse
• 30% occasional relapses
• 30% steroid dependence

Question 17

suggest possible complications of nephrotic syndrome

Answer 17

1. infection esp. bacterial peritonitis due to decreased IgG levels and impaired opsonisation from steroid use
2. arterial or venous thrombosis due to hypercoagulable state
3. hypovolaemia + pre-renal AKI

Question 18

What is vesicoureteric reflux and what are the causes of this?

Answer 18

Retrograde flow of urine from the bladder into the ureters/kidneys due to failure of valve-like effect at vesicoureteric junction.

Causes:

1. primary - familial developmental anomaly at the vesicoureteric junctions: ureters are displaced laterally and enter directly into the bladder rather than at an angle, with a shortened or absent intramural course.
2. secondary - may occur with:
   - bladder pathology e.g. neuropathic bladder
   - urethral obstruction
   - temporarily after a UTI

Question 19

Why does severe VUR cause renal damage?

Answer 19

Due to:

1. intrarenal reflux: backflow of urine from renal pelvis into papillary collecting ducts
2. pyelonephritis: urine returns to bladder from dilated ureters after voiding… incomplete bladder emptying which encourages infection… renal scaring
3. bladder voiding pressure may be transmitted to renal papillae

If scarring is bilateral and severe, progressive CKD may develop.

Question 20

How might vesicoureteric reflux present? How would you investigate?

Answer 20

Presentation:

• often asymptomatic in mild cases
• recurrent UTIs in more severe cases

Investigations:

• micturating cystourethrogram: to diagnose and grade severity of reflux
• DMSA scan: may be performed to look for renal scarring

Question 21

What is the management and prognosis of VUR?

Answer 21

Mild cases
- tend to resolve with age

Severe cases

• may require surgery
• if bilateral, 10% risk of HTN in childhood or early adult life