Paediatric urology: antenatal findings, infection imaging and surgical timing
What the exam tests
Antenatal hydronephrosis pathways, imaging after childhood urinary infection, timing of elective surgery in congenital anomalies, and the emergencies that must not be delayed.
Core rules
- Antenatal hydronephrosis is graded and reassessed after birth; repeat ultrasound is usually done after 48 to 72 hours because very early scans underestimate dilatation. Micturating cystourethrography is used for suspected vesicoureteric reflux or bladder outlet obstruction; a MAG3 renogram assesses drainage and differential function.
- Febrile urinary tract infection in infancy warrants ultrasound; recurrent infections warrant DMSA scanning for cortical scarring.
- Undescended testis: refer by six months and perform orchidopexy by 12 to 18 months to reduce malignancy and infertility risk.
- Hypospadias: never circumcise before repair, because the foreskin may be needed for urethroplasty. Refer for repair between 6 and 12 months.
- Posterior urethral valves present in a male infant with poor stream, palpable bladder and bilateral hydronephrosis; catheterise and arrange endoscopic ablation.
- Acute scrotal pain in a child is torsion until proven otherwise; exploration within six hours is the priority.
Worked example
A two-year-old boy has his first febrile urinary tract infection. Reasoning: ultrasound is first-line, looking for obstruction and structural abnormality. If the ultrasound is abnormal, or the infection is atypical or recurrent, proceed to micturating cystourethrography for reflux and consider DMSA for cortical scarring.
Traps
Circumcising a hypospadias; delaying exploration for suspected torsion to obtain a Doppler; ordering a cystogram before ultrasound in a first febrile infection; forgetting that very early postnatal scans underestimate dilatation.