Acute Kidney Injury in Children

Introduction

Acute Kidney Injury is a significant cause of morbidity (electrolyte derangements, disordered coagulation and endocrine dysfunction) and mortality in children.
It is defined as a sudden, rapid and progressive deterioration in renal function resulting in the inability of the kidneys to perform its homeostatic function.
Manifested as a rise in plasma urea, creatinine and accompanied by oliguria and occasionally polyuria.
It is recently referred to as acute kidney injury with RIFLE staging (Risk Injury Failure Loss End Stage).
Serum creatinine and urinary output are parameters used, the worst of the two being used to stage.
Key words

  • Oliguria: reduction in urinary output <= 300ml/m² or <1ml/kg/hr
  • Anuria: reduction in urinary output to < 1ml kg/day
  • Polyuria: urine output> 4ml kg/hr
  • Azotemia: high nitrogeneous waste indicated by high urea
  • Uraemia: symptom complex reflecting organ dysfunction occurring when the kidney fails to regulate body composition

Cause of renal injury:

  1. Pre-renal,
  2. Intrinsic renal
  3. Post renal.

Commonest causes of renal injury in pediatrics are often pre-renal and are due largely to preventable causes
Least common cause is post renal.
50% acute kidney injury in children are non oliguric.
Incidence is difficult because of non standardized definition.
AKI is seen in 5% of children admitted into ICU.
Reported rates have been between 3.13% to 57.9%

Pre renal:

Mainly due to volume loss –

  • Diarrhoea
  • Vomiting,
  • Haemorrhage

Intrinsic:

Native disease of the kidney –

  • Acute glomerulonephritis,
  • Nephrotic syndrome
  • Complicated malaria
  • Septicaemia

Post renal:

Usually due to obstruction

  •  Posterior urethral valve
  • Urethral stricture
  • Pelvi- ureteric junction obstruction,
  • Vesico -ureteric junction obstruction,
  • Neurogenic bladder

Clinical features

  • Fluid retention
  • Oliguria
  • Anuria
  • Oedema
  • Dyspnea
  • Hypertension →→convulsion
  • Congestive cardiac failure
  • Pallor
  • Acidotic breathing
  • Features of underlying disease

Investigations

  • Complete blood count
  • Malaria parasite
  • Serum electrolyte urea, creatinine
  • Others as indicated may include MCUG

Treatment

Objectives:

  • To prevent progression of failure
  • To rapidly restore volume in pre-renal cases
  • To treat the underlying cause

Drug Treatment

  • Fluid management
  • Blood transfusion in case of acute loss
  • Relieve obstruction,
  • Dialysis
  • Anti malarial
  • Antibiotics