Glomerulonephritis

Question 1

GN - background

Answer 1

1. Def = glomerular inflammation/injury
2. Leads to a constellation of sx which include haematuria, oliguria, edema, HTN, variable proteinuria
3. Majority of cases post-infectious

Question 2

Acute GN - causes (5+5)

Answer 2

Post-infectious

1. Bacterial = streptococcal commonest, staphylococcus aureus
2. Mycoplasma pneumoniae, Salmonella
3. Viruses = herpesviruses (EBV, varicella, CMV)
4. Fungi = candida, aspergillus
5. Parasites = toxoplasma, malaria, schistosomiasis

Others (less common)

1. MPGN
2. IgA nephropathy
3. Systemic lupus erythematosis
4. Subacute bacterial endocarditis
5. Shunt nephritis (rare, in children with shunts for hydrocephalus)

Question 3

GN - ix

Answer 3

1. Urine
   a. Urinalysis by dipstick = haematuria +/- proteinuria
   b. Microscopy = casts (mostly red cell casts)
2. Throat swab - culture
3. Bloods
   a. FBE
   b. UEC including (5): creatinine, bicarbonate, calcium, phosphate and albumin
   c. ASOT/anti-DNAase B
   d. Complement (expect low C3, normal C4 - ?)
   e. Autoantibody screen (including ANA)
4. Renal U/S (urgent)
5. CXR (if fluid overload suspected)

Question 4

GN - mx

Answer 4

1. Most require admission bc fluid balance, worsening renal function or HTN
2. Tx life-threatning complications first (5)
   a. Hyperkalaemia
   b. HTN
   c. Acidosis
   d. Seizures
   e. Hypocalcaemia

Otherwise, supportive tx:

3. Fluid balance (3)
   a. Weigh daily + no added/restricted salt diet
   b. If oliguric, fluid restrict to insensible losses (400mL/m2) + urine output
   c. Consider frusemide 1-2mg/kg bd if fluid overload
4. HTN
   - Tx fluid overload, alpha-blockers and CCB usual first choice
5. Infection
   - 10d course of penicillin (does not affect natural history, but limits spread of nephritogenic bacterial strains)

Question 5

GN - when to refer to paediatric nephrology unit

Answer 5

1. Life-threatening complications (5)
2. Atypical features, including:
   a. Worsening renal function
   b. Nephrotic state
   c. Evidence of systemic vasculitis (e.g. rash)
   d. Low C3 (?), increased C4 (?) or positive ANA
   e. Persisting proteinuria at 6 wks

Question 6

GN - prognosis

Answer 6

1. 95% with post-streptococcal GN show complete recovery
2. Microscopic haematuria may persist for 1-2y
3. Discharge from F/U once urinalysis, BP and creatinine are normal

Question 7

Post-streptococcal GN vs. IgA nephropathy

Answer 7

• IgA nephropathy 1-2 weeks after URTI

- Post-streptococcal GN 1-3wks after URTI