Paediatrics: Glomerulonephritis

Glomerulonephritis

A combination of haematuria, oliguria, oedema, and hypertension with variable proteinuria.

·  Majority of cases post-infectious.

·  Usually presents 1–2wks after a URTI and sore throat.

Causes of acute glomerulonephritis

Post-infectious

·  Bacterial: streptococcal commonest, Staphylococcus aureus,

·  Mycoplasma pneumoniae, Salmonella

·  Virus: herpesviruses (EBV, varicella, CMV)

·  Fungi: candida, aspergillus

·  Parasites: toxoplasma, malaria, schistosomiasis

Others (less common)

·  MPGN

·  IgA nephropathy

·  Systemic lupus erythematosis

·  Subacute bacterial endocarditis

·  Shunt nephritis

Investigations

·  Urine:

o urinalysis by dipstick: haematuria +/– proteinuria;

o microscopy—casts (mostly red cell casts).

·  Throat swab: culture.

·  Bloods:

o FBC;

o U&E, including creatinine, bicarbonate, calcium, phosphate, and

o albumin;

o ASOT/antiDNAase B;

o complement (expect low C3, normal C4);

o autoantibody screen (include ANA).

·  Renal US (urgent).

·  CXR (if fluid overload suspected).

Management

Most require admission because of fluid balance, worsening renal function, or hypertension. Treat life-threatening complications first:

·hyperkalaemia;

·hypertension;

·acidosis;

·seizures;

·hypocalcaemia.

Otherwise supportive treatment.

·Fluid balance:

·  weigh daily;

·  no added/restricted salt diet;

·  if oliguric, fluid restrict to insensible losses (400mL/m²) + urine

·  output;

·  consider furosemide 1–2mg/kg bd if fluid overloaded.

·Hypertension:

o treat fluid overload;

o α-blockers and calcium channel blocker usual first choice;

o Note: Do not use ACE inhibitor (may worsen renal function).

·Infection: 10-day course of penicillin (does not affect natural history, but limits spread of nephritogenic bacterial strains).

When to refer to paediatric nephrology unit

·Patients with life-threatening complications (see Management).

·Those with atypical features, including:

·  worsening renal function;

·  nephrotic state;

·  evidence of systemic vasculitis (e.g. rash);

·  normal C3 complement levels;

·  increased C4 complement levels;

·  +ve ANA;

·  persisting proteinuria at 6wks;

·  persisting low C3 at 3mths.

Prognosis

·95% with post-streptococcal glomerular nephritis (GN) show complete recovery.

·Microscopic haematuria may persist for 1–2yrs.

·Discharge from follow-up once urinalysis, BP, and creatinine are normal.