Neonatal Acute Kidney Injury (AKI)

Presentation & Risk Factors

• Extreme prematurity
• Hypoxic-Ischemic Encephalopathy (HIE) or outborn asphyxia
• Congenital heart disease, specifically requiring cardiopulmonary bypass
• Exposure to nephrotoxic medications (Gentamicin, Vancomycin, Indomethacin, Ibuprofen)
• Oliguria (< 1 mL/kg/h urine output after the first 24 hours of life)

Diagnostic Evaluation

• Strict monitoring of urine output geometry (weigh diapers diligently)
• Serum Creatinine (interpret with caution in first 1-2 weeks as it reflects maternal creatinine initially)
• Follow KDIGO neonatal AKI definition criteria (rise in SCr by >= 0.3 mg/dL within 48h, or urine output < 0.5 mL/kg/hr for 6-12 hours)
• Renal bladder ultrasound to rule out obstructive uropathy or congenital anomalies (CAKUT)

Management Principles

• Optimize hemodynamics and volume status (fluid bolus only if definitively hypovolemic; strictly avoid fluid overload)
• Strict fluid restriction (often only insensible losses + measured output) if oligoanuric
• Discontinue or dose-adjust all nephrotoxic medications
• Monitor for and treat hyperkalemia, hyponatremia, and severe metabolic acidosis
• Consider peritoneal dialysis/CRRT consultation if medically refractory

Renal & Fluid Protocol

• Weigh all diapers to exact gram to calculate precise urine output.
• Flush all umbilical lines exclusively with Heparin-locked saline (0.5 to 1 U/mL).
• If prescribing aminoglycosides, adjust interval (e.g., q36h or q48h) according to fluctuating serum creatinine.
• Monitor for extreme hyperkalemia: ECG check for peaked T-waves, administer IV Calcium Gluconate (10%) 100 mg/kg over 15 mins for immediate cardioprotection.

Standardized Discharge & Follow-Up Criteria

• Adequate weight gain explicitly > 15-30g/day over a continuous 3-5 day period.
• Maintenance of temperature in an open crib with standard clothing for 48 hours.
• Successful completion of the 90-120 minute Infant Car Seat Challenge.
• Caregiver successfully completed CPR training, rooming-in, and independent medication administration.
• Referrals placed for High-Risk Infant Follow-Up Clinic, Early Intervention (PT/OT), and appropriate sub-specialists.

Diagnostic & Management Algorithm

• AKI Management: [START] Elevated Creatinine -> [DECISION] Volume Status? -> [YES] Overload: Furosemide -> [NO] Dehydration: Fluid Bolus -> [EVALUATE] UOP Response

References

1. Jetton JG, Askenazi DJ. Update on acute kidney injury in the neonate. Curr Opin Pediatr.
2. Zappitelli M, Ambalavanan N, Askenazi DJ, et al. Developing a neonatal acute kidney injury research definition: a report from the NIDDK neonatal AKI workshop. Pediatr Res.