Renal failure

Acute renal failure (ARF) or acute kidney injury (AKI) features decreased glomerular filtration rate (GFR) that leads to electrolyte and water metabolism disturbances and distortion of acid base homeostasis. The infants should be followed up by a pediatric nephrologist (hypertension, congenital anomalies).

The basic division:

  • prerenal
    hypovolemia (sepsis, shock, hemorrhage, dehydration)
    cardiac failure (congenital heart defects)
    hypoxia (perinatal asphyxia)
  • renal
    acute tubular/cortical necrosis (ATN) (sepsis, perinatal asphyxia, tubular obstruction, nephrotoxic agents)
    vascular issues (renal vein/arterial thrombosis)
    congenital malformations (renal agenesis/dysplasia, polycystic kidneys)
  • postrenal
    → obstruction due to malformation (posterior urethral valve, pelvic obstruction)
    neurogenic urinary bladder (hypoxic-ischemic encephalopathy, spina bifida)

DIAGNOSIS

Clinical signs

  • oliguria/anuria
  • edema
  • hypertension

Laboratory findings

  • elevated urea and creatinine
  • electrolyte abnormalities (hyponatremia, hyperkalemia)
  • metabolic acidosis
  • fractional excretion of sodium (FE-Na) < 1% indicates prerenal failure or acute glomerulonephritis, whereas FE-Na > 2-3% indicates most cases of ATN, pre-existing chronic renal failure or following diuretic treatment
  • renal failure indices may be inconclusive and unreliable in preterm newborns

Imaging

  • ultrasound of the kidneys (congenital anomalies, parenchymal changes, Doppler flowmetry for vascular issues – thrombosis)

THERAPY

Conservative management

  • cure the original cause of AFI (poor cardiac output, hypovolemia, hemorrhage, etc)
  • fluid balance (depends on the origin of renal failure!)
  • nutrition (lower protein intake, energy requirements)
  • correction of metabolic acidosis and hyperkalemia
  • antihypertensive drugs

Invasive management

  • peritoneal dialysis

REFERENCES

① Andreoli SP. Acute renal failure in the newborn. Semin Perinatol. 2004;28(2):112-123. doi:10.1053/j.semperi.2003.11.003

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