Chapter 99: Acute Kidney Injury in Neonates and Infants

DIAGNOSIS/INDICATIONS

Clinical Findings

1. Increasing serum creatinine (Cr)

2. Decreasing urine output to less than 0.5–1 mL/kg/h

History and Physical Examination

Table 99-1 provides information on the history and physical examination.

Additional Workup

1. Check electrolytes, complete blood cell count (CBC)

2. Consider urinalysis, urine sodium, urine urea, urine Cr (FeNa, FeUrea)

3. Consider renal ultrasound (RUS) with Doppler to evaluate structure and blood flow

Diagnostic Algorithm

1. Consider prerenal, intrinsic, postrenal (obstructive) causes of acute kidney injury (AKI)

2. Clues to prerenal AKI

   1. Hypovolemia on examination

   2. Decreased weight

   3. Negative fluid balance

   4. FeNa less than 2.5% or FeUrea less than 35%

      FeNa = (Urine Na × Plasma Na) × 100(Urine Cr × Plasma Cr)
      FeUrea = (Urine Urea × Plasma Serum Urea Nitrogen) × 100(Urine Cr × Plasma Cr)

3. Clues to intrinsic AKI

   1. Prolonged hypovolemia or hypotension

   2. Exposure to nephrotoxic medication

   3. Presence of clinical conditions associated with AKI

      • (1) Sepsis/multiorgan dysfunction syndrome

      • (2) Congenital cardiac surgery

      • (3) Perinatal asphyxia

      • (4) Extracorporeal membrane oxygenation (ECMO)

4. Clues to postrenal (obstructive) AKI

   1. Prenatal history of hydronephrosis/other urologic anomaly

   2. Potter syndrome

   3. Abdominal mass

   4. RUS showing thickened bladder wall, dilated collecting system, hydronephrosis

TREATMENT/MANAGEMENT ALGORITHM

1. Assess fluid status; fluid resuscitate if hypovolemic

2. Ensure blood pressure is adequate for renal perfusion

   1. Volume resuscitation

   2. Vasopressor support if needed

3. Consider urethral Foley catheter placement

   1. Relieves possible obstruction.

   2. Facilitates strict in and out measurement.

   3. Measures intravesical pressure via Foley catheter if there is concern for abdominal compartment syndrome. In children and infants, abdominal compartment syndrome has been described in those with intraabdominal pressures greater than 10–12 mm Hg.

4. Consider acute management therapies for intrinsic AKI

   1. Rasburicase 0.2 mg/kg IV once if serum uric ...