Pediatrics
Genitourinary System
Paediatric renal and genitourinary disease for NEET-PG: UTI, APSGN, nephrotic syndrome, Wilms tumour, reflux and posterior urethral valves, mapped to NMC PE21 codes.
MedNext Academy | 3 min read
Genitourinary System
Paediatric renal and genitourinary disease for NEET-PG: UTI, APSGN, nephrotic syndrome, Wilms tumour, reflux and posterior urethral valves, mapped to NMC PE21 codes.
This chapter covers paediatric renal and genitourinary disease, from urinary tract infection, glomerulonephritis and nephrotic syndrome through acute and chronic kidney disease to structural anomalies such as posterior urethral valves, reflux and undescended testis. It emphasises the Indian burden of CAKUT-driven chronic kidney disease.
High-yield: Genitourinary System
- A febrile urinary tract infection implies possible pyelonephritis, so nitrofurantoin, useful for lower cystitis, is the wrong drug when fever suggests renal parenchymal involvement.
- In acute post-streptococcal glomerulonephritis a low C3 that normalises by 6 to 8 weeks is classic, while a persistently low C3 is a clue to another glomerular disease.
- In childhood nephrotic syndrome the prednisolone response is both treatment and classification, since steroid-sensitive disease carries a good renal prognosis.
- A nephrotic child with abdominal pain and fever has spontaneous bacterial peritonitis until proven otherwise, and should not be dismissed as ascites stretch.
- The three questions in acute kidney injury are perfusion, obstruction and intrinsic renal disease, and hyperkalaemia is treated before the full diagnosis is complete.
- In chronic kidney disease proteinuria and hypertension are progression accelerators, and staging by eGFR is incomplete without urine protein and blood pressure.
- A painless abdominal mass in a 2 to 5 year old is Wilms tumour until imaging proves otherwise, with neuroblastoma as the key differential.
- Voiding cystourethrogram diagnoses and grades vesicoureteral reflux, whereas a DMSA scan assesses renal cortical scarring; they answer different questions.
- Distal renal tubular acidosis is an inability to acidify urine and proximal is bicarbonate wasting; both cause a normal anion gap metabolic acidosis with different potassium patterns.
- The haemolytic uraemic syndrome triad is microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury, and platelets are low but not routinely transfused.
- A boy with a urinary tract infection must be asked about his urinary stream, because a poor stream is a posterior urethral valve clue until proven otherwise.
- Posterior urethral valve ablation fixes the obstruction but not the whole disease, since valve bladder and renal dysplasia decide long-term outcome.
- Orchiopexy for an undescended testis should be completed in infancy, typically at 6 to 18 months, and not delayed to school age or puberty.
- Most infant hydroceles resolve by 12 to 18 months, so a persistent or communicating hydrocele is a surgical referral rather than repeated aspiration.
- Congenital anomalies of the kidney and urinary tract are the leading cause of paediatric chronic kidney disease, and follow-up must track blood pressure, proteinuria and growth.
Complement and imaging clues
- **Low C3 in acute nephritis:** Normalises by 6 to 8 weeks in APSGN; persistent low C3 suggests another glomerular disease.
- **Steroid response in nephrotic syndrome:** Steroid sensitivity confirms good renal prognosis; resistance changes the whole pathway.
- **VCUG vs DMSA:** VCUG grades vesicoureteral reflux; DMSA assesses cortical scarring.
- **Poor urinary stream in a boy:** A posterior urethral valve clue until proven otherwise on imaging.
NMC competencies in this chapter
- **PE21.1:** Urinary Tract Infection in Children
- **PE21.2:** Acute Post-Streptococcal Glomerulonephritis
- **PE21.3:** Nephrotic Syndrome in Children
- **PE21.6:** Wilms Tumour
- **PE21.8:** Vesicoureteral Reflux
- **PE21.11:** Posterior Urethral Valves
- **PE21.17:** Congenital Anomalies of Kidney and Urinary Tract
Frequently Asked Questions
Why is nitrofurantoin the wrong choice for a febrile urinary tract infection?
Fever implies possible pyelonephritis with renal parenchymal involvement. Nitrofurantoin does not achieve adequate tissue and renal levels, so it is reserved for lower cystitis rather than febrile upper-tract infection.
What does the C3 level tell you in acute nephritis?
In acute post-streptococcal glomerulonephritis C3 is low and typically normalises by 6 to 8 weeks. A C3 that stays persistently low is a clue to a different glomerular disease such as membranoproliferative disease or lupus nephritis.
How do VCUG and DMSA differ?
A voiding cystourethrogram diagnoses and grades vesicoureteral reflux, while a DMSA scan detects renal cortical scarring. They answer different clinical questions and are often used together.
What is the leading cause of chronic kidney disease in children?
Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading paediatric cause. Management must include lifelong follow-up of blood pressure, proteinuria and growth, not merely naming the anomaly.
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