ABP Pediatric Nephrology common mistakes
ABP Pediatric Nephrology · Understand the traps and how to avoid them.
For a 5-year-old with edema, heavy proteinuria, albumin under 2 g/dL, normal blood pressure, normal creatinine, and normal C3, orders a renal biopsy and delays corticosteroids until the result returns.
Adult nephrology habits and fear of missing a treatable lesion lead to reflexive biopsy; the pediatric age- and feature-based exception for presumptive steroid-sensitive nephrotic syndrome is not recalled under time pressure.
What to do instead
Memorize the presumptive steroid-sensitive criteria (age 1–10 years, pure nephrotic features, normal blood pressure, no gross hematuria, normal creatinine, normal complement, no extrarenal signs) and reserve biopsy for age extremes, atypical features, secondary causes, steroid resistance, or frequent relapses.
Decides between post-infectious glomerulonephritis and IgA nephropathy using only the timing of hematuria relative to the sore throat, without ordering C3 and C4 or rechecking C3 weeks later.
The two conditions overlap heavily in presentation and the latent period is an unreliable discriminator; the complement pattern and its trajectory are the actual distinguishing test.
What to do instead
Order C3 and C4 at presentation and repeat C3 at 6–8 weeks: a low C3 that normalizes supports post-infectious GN, a persistently low C3 suggests MPGN or C3 glomerulopathy, and a normal C3 points toward IgA nephropathy or thin basement membrane disease.
Interprets a fractional excretion of sodium of 2% in a child receiving furosemide as proof of intrinsic tubular injury, or applies the adult 1% cutoff to a preterm neonate.
The adult FeNa thresholds are overlearned, but loop diuretics raise FeNa independently of tubular damage and healthy preterm infants normally excrete a high sodium fraction.
What to do instead
When diuretics are on board, use FEUrea (under 35% suggests prerenal) or bedside volume and ultrasound assessment; apply age-specific reference values and remember that a fluid challenge or repeat measurement carries more information than a single FeNa.
Labels a 10-year-old with a blood pressure of 128/84 mmHg as normotensive because it is under 140/90, or calls a child hypertensive without indexing to age, sex, and height.
Adult 140/90 criteria are deeply overlearned, while pediatric thresholds are percentile-based and must be looked up rather than estimated, so intuition silently substitutes for the table.
What to do instead
Use the AAP 2017 tables: stage 1 hypertension is at least the 95th percentile for age, sex, and height; stage 2 is at least the 95th percentile plus 12 mmHg or at least 140/90; for adolescents 13 years and older use 130/80. Confirm with the correct cuff size on repeat visits, and measure all four limbs when coarctation is a consideration.
Concludes a child has no acute kidney injury because the serum creatinine of 0.8 mg/dL sits within the laboratory reference range for age, despite a documented baseline of 0.4 mg/dL two months earlier.
Absolute laboratory reference ranges are used as the decision rule instead of change from baseline, and creatinine lags behind injury while being diluted by fluid overload and low muscle mass.
What to do instead
Apply KDIGO or pRIFLE criteria: a rise of at least 0.3 mg/dL within 48 hours or at least 1.5 times baseline within 7 days, plus urine output under 0.5 mL/kg/h. Reconstruct the baseline from prior values or age-based norms and correct the interpretation for fluid balance.
Gives antibiotics and an antimotility agent to a toddler with bloody diarrhea who then develops anemia, thrombocytopenia, and rising creatinine.
The diarrhea is handled as routine gastroenteritis; the link between Shiga toxin-producing E. coli and hemolytic uremic syndrome, and the specific harm of these drugs, is not retrieved quickly enough during the encounter.
What to do instead
In suspected STEC-HUS, avoid antibiotics and antimotility agents, send stool for Shiga toxin and E. coli O157:H7, provide meticulous supportive care with attention to fluid, sodium, and potassium balance, and reserve eculizumab for complement-mediated atypical HUS.
Starts recombinant growth hormone in a short child with CKD stage 4 before correcting metabolic acidosis, hyperparathyroidism, anemia, and inadequate energy or protein intake.
Short stature in CKD is treated as a single hormone deficiency, when growth failure is multifactorial and growth hormone resistance is only one contributor among several reversible ones.
What to do instead
Optimize nutrition with a renal dietitian, normalize bicarbonate, control phosphorus and PTH, and treat anemia and iron deficiency first; then start growth hormone for persistent height below the 3rd percentile or height velocity SDS below −2 in CKD stages 3–5, monitoring for intracranial hypertension and glucose intolerance.
Prescribes a standard 4-hour hemodialysis session with a large-surface-area dialyzer and rapid ultrafiltration for a 9-kg infant with AKI and hypotension.
Adult dialysis prescriptions are applied by default, but extracorporeal circuit volume, solute shift rates, and hemodynamic reserve all scale with body size in ways that are not intuitive.
What to do instead
Size the circuit and dialyzer to the child (aim for extracorporeal volume under roughly 10% of patient blood volume), limit blood flow and ultrafiltration rate, consider CRRT or peritoneal dialysis for hemodynamically unstable infants, and monitor for dialysis disequilibrium with a planned, slower first session.
Treats a rising creatinine six months after kidney transplantation with empiric pulse steroids before checking the tacrolimus trough, BK viral load, donor-specific antibodies, and urine protein.
Rejection is assumed to be the only cause of graft dysfunction, when calcineurin inhibitor toxicity, BK nephropathy, recurrent disease, obstruction, and volume depletion all present identically as a creatinine rise.
What to do instead
Work through a structured algorithm first: drug level, urinalysis with protein-to-creatinine ratio, BK PCR, donor-specific antibody testing, and graft ultrasound with Doppler; obtain a biopsy when the cause remains unclear, and escalate immunosuppression only with a diagnosis.
Orders a voiding cystourethrogram and continuous antibiotic prophylaxis for every infant with mild antenatal hydronephrosis identified on a single prenatal ultrasound.
All hydronephrosis is treated as obstruction or reflux, so risk stratification by grade and the high rate of spontaneous resolution of mild pelvic dilation are ignored.
What to do instead
Confirm postnatally with ultrasound at 48–72 hours in term infants or at 3–7 days in preterm infants, grade using the UTD classification, reserve VCUG for high-grade dilation, ureteral dilation, duplex or abnormal findings, or suspected posterior urethral valves, and use prophylaxis only in high-risk groups.