Pediatric Nephrology and Urology
Core concepts
Understand fluid and electrolyte physiology and the approach to dehydration (assess severity, use isotonic fluids for resuscitation). Know urinary tract infection diagnosis (urine culture before antibiotics, age-dependent presentation) and imaging indications. Recognize vesicoureteral reflux and hydronephrosis (antenatal detection, postnatal ultrasound). Understand glomerular disease: nephrotic syndrome (proteinuria, hypoalbuminemia, edema, hyperlipidemia; steroid-responsive in most children) versus nephritic syndrome (hematuria, hypertension, oliguria; post-streptococcal glomerulonephritis). Know hematuria workup (glomerular vs nonglomerular). Understand acute kidney injury (prerenal vs intrinsic vs postrenal) and chronic kidney disease complications (anemia, growth failure, renal osteodystrophy). Recognize posterior urethral valves (male infant, weak stream, hydronephrosis) and testicular torsion (acute scrotal pain - surgical emergency).
Traps
- Treating nephrotic syndrome with diuretics alone or missing infection risk (peritonitis, sepsis).
- Confusing nephritic and nephrotic presentations.
- Missing testicular torsion because of a presumed epididymitis diagnosis.
- Forgetting that a normal urinalysis does not exclude UTI in infants - obtain culture.
- Overlooking hypertension as a cause of seizures or encephalopathy in children.
Worked example / rule of thumb
A 4-year-old with periorbital edema, frothy urine, and hypoalbuminemia: diagnose nephrotic syndrome, check urine protein, and start corticosteroids per protocol; monitor for infection and thrombosis. Rule of thumb: nephrotic = proteinuria + edema + hypoalbuminemia; nephritic = hematuria + hypertension + oliguria; acute scrotal pain = torsion until excluded.