ABU Pediatric Urology cheat sheet

Wilms tumor: most common pediatric renal malignancy, peak age 3-4 years; associated with WT1 mutations, WAGR, Beckwith-Wiedemann; staging by NWTS/COG; treatment nephrectomy + chemotherapy ± radiation.

Neuroblastoma: most common extracranial solid tumor in children; arises from neural crest; elevated urinary VMA/HVA; often calcified on imaging; surgical resection ± chemo/radiation.

Rhabdomyosarcoma of bladder/prostate: most common lower urinary tract malignancy in children; embryonal or alveolar histology; treatment multimodal (chemo + surgery + radiation); bladder preservation when possible.

Testicular tumors in prepubertal boys: yolk sac tumor most common; present as painless scrotal mass; AFP elevated; radical inguinal orchiectomy; excellent prognosis.

Renal cell carcinoma: rare in children; associated with von Hippel-Lindau, tuberous sclerosis; presents with hematuria, flank pain; treatment nephrectomy.

Adrenal tumors: adrenocortical carcinoma and pheochromocytoma; pheo associated with MEN2, VHL; elevated catecholamines/metanephrines; alpha-blockade before surgery.

Ovarian tumors: germ cell tumors most common; mature teratoma benign; yolk sac tumor elevated AFP; dysgerminoma elevated LDH; management ovary-sparing when feasible.

Bladder urothelial tumors: rare in children; painless gross hematuria; associated with schistosomiasis in endemic areas; TURBT for diagnosis and treatment.

Ureteropelvic junction obstruction: most common cause of prenatal hydronephrosis; diagnosed by renal ultrasound and diuretic renogram; treatment pyeloplasty if obstruction and/or declining renal function.

Vesicoureteral reflux (VUR): graded I-V by VCUG; grade I- III often managed medically with antibiotic prophylaxis; grades IV-V may require ureteral reimplantation or endoscopic injection.

Posterior urethral valves: most common cause of lower urinary tract obstruction in boys; prenatal ultrasound shows keyhole sign, thickened bladder; treatment bladder drainage then valve ablation.

Hypospadias: ventral urethral meatus, dorsal hooded foreskin, chordee; avoid circumcision; repair at 6-18 months; severity based on meatal location.

Cryptorchidism: undescended testis; risk of infertility and malignancy; orchiopexy by 12-18 months; palpable vs nonpalpable; use ultrasound only for nonpalpable.

Multicystic dysplastic kidney: nonfunctioning kidney with multiple cysts; usually unilateral; contralateral kidney normal; management observation with serial ultrasound; nephrectomy if symptomatic.

Prune belly syndrome: triad of deficient abdominal wall musculature, cryptorchidism, urinary tract anomalies; often associated with renal dysplasia and pulmonary hypoplasia.

Bladder exstrophy: infraumbilical abdominal wall defect, exposed bladder mucosa, epispadias; staged reconstruction (closure, epispadias repair, bladder neck reconstruction).

Normal bladder capacity in children: (age in years + 2) × 30 mL; expected voiding frequency 4-7 times/day; post-void residual <10% capacity.

Dysfunctional voiding: pelvic floor contraction during voiding; staccato or interrupted stream; diagnosed by uroflow with EMG; treatment biofeedback and pelvic floor relaxation.

Overactive bladder: urgency, frequency, urge incontinence; uninhibited detrusor contractions on urodynamics; treatment bladder training, anticholinergics (oxybutynin), beta-3 agonist (mirabegron).

Neurogenic bladder: due to spinal dysraphism (myelomeningocele), spinal cord injury, tethered cord; urodynamics to assess compliance and leak point pressure; clean intermittent catheterization (CIC) and anticholinergics to protect kidneys.

Myelomeningocele: most common cause of neurogenic bladder in children; 80% have bladder dysfunction; urodynamic risk factors: detrusor leak point pressure >40 cm H2O, poor compliance, VUR.

Tethered cord: can cause progressive bowel/bladder dysfunction, lower extremity weakness; MRI for diagnosis; neurosurgical release.

Uroflowmetry: noninvasive test; bell-shaped curve normal; plateau curve suggests obstruction; staccato curve suggests dysfunctional voiding.

Biofeedback: effective for dysfunctional voiding and constipation; teaches pelvic floor relaxation during voiding.

Pediatric urolithiasis: increasing incidence; most common composition calcium oxalate; risk factors: low fluid intake, metabolic abnormalities (hypercalciuria, hyperoxaluria, cystinuria), anatomic anomalies, infection.

Metabolic evaluation: 24-hour urine collection (or spot urine for younger children) for calcium, oxalate, citrate, uric acid, cystine; serum electrolytes, PTH, vitamin D.

Acute management: pain control (NSAIDs), hydration; stones <5 mm often pass spontaneously; stones >10 mm or obstructing with infection require urgent decompression (stent or nephrostomy).

ESWL: first-line for renal stones <1 cm in children; less effective for lower pole stones; complications: hematuria, colic, steinstrasse.

URS: preferred for ureteral stones; holmium laser lithotripsy; high stone-free rates; stent placement often needed.

PCNL: for large renal stones (>1-2 cm) or complex anatomy; mini-PCNL reduces morbidity in children.

Cystinuria: autosomal recessive; defective renal tubular reabsorption of cystine, ornithine, lysine, arginine; treatment hyperhydration, alkalinization, chelators (penicillamine, tiopronin).

Infection stones: struvite (magnesium ammonium phosphate) due to urease-producing bacteria (Proteus); require complete stone removal and eradication of infection.

Renal trauma: most common pediatric genitourinary injury; grading I-V by CT; hemodynamically stable patients managed nonoperatively; absolute indication for surgery: hemodynamic instability.

Ureteral injury: rare; often iatrogenic; presents with urinoma or hydronephrosis; treatment stent or surgical repair depending on extent.

Bladder injury: usually associated with pelvic fracture; extraperitoneal vs intraperitoneal; intraperitoneal requires surgical repair; extraperitoneal often catheter drainage.

Urethral injury: suspect with blood at meatus, perineal hematoma, inability to void; retrograde urethrogram for diagnosis; suprapubic catheter if unable to place urethral catheter; delayed repair for stricture.

Testicular trauma: ultrasound if uncertain; scrotal exploration for suspected rupture; salvage rate high if repaired within 72 hours.

Hypospadias repair: goals: straight penis, meatus at tip, normal voiding, acceptable cosmesis; techniques: tubularized incised plate (TIP), onlay graft; complications: fistula, stricture, diverticulum.

Ureteropelvic junction obstruction repair: pyeloplasty (open, laparoscopic, robotic); success rate >90%; stent or nephrostomy drainage postoperatively.

Bladder augmentation: for small capacity, poor compliance bladder; using bowel (ileum, colon) or stomach; complications: metabolic acidosis, mucus, stones, perforation, malignancy.

Urinary tract infection (UTI): common in children; febrile UTI may cause renal scarring; diagnosis by urinalysis and urine culture; treatment depends on age and severity; neonates and infants often require parenteral antibiotics.

Vesicoureteral reflux (VUR) and UTI: VUR increases risk of pyelonephritis and renal scarring; antibiotic prophylaxis for high-grade VUR or recurrent UTIs.

Acute pyelonephritis: fever, flank pain, elevated inflammatory markers; imaging (ultrasound) to rule out abscess or obstruction; treatment IV antibiotics then oral.

Renal abscess: complication of pyelonephritis; ultrasound or CT diagnosis; treatment antibiotics and drainage if large.

Epididymitis: scrotal pain and swelling; in children often due to urinary tract anomaly or sexual abuse; treat with antibiotics and scrotal support; differentiate from testicular torsion.

Balantis/posthitis: inflammation of glans/prepuce; usually due to poor hygiene; treatment hygiene and topical antibiotics; circumcision for recurrent cases.

Fournier gangrene: necrotizing fasciitis of perineum; rare in children; emergency debridement and broad-spectrum antibiotics.

Schistosomiasis: parasitic infection; causes bladder granulomas and hematuria; associated with squamous cell carcinoma of bladder; treatment praziquantel.

Glomerular filtration rate (GFR): normal in children >90 mL/min/1.73m2; estimated by Schwartz formula: eGFR = 0.413 × height (cm) / serum creatinine (mg/dL).

Renal blood flow: high in neonates (20% cardiac output) and increases with age; autoregulation maintains GFR.

Hypertension in children: defined as BP ≥95th percentile for age, sex, height; secondary causes common in young children (renal parenchymal disease, coarctation, endocrine); renal ultrasound and labs for evaluation.

Renal transplantation: preferred treatment for end-stage renal disease in children; living donor preferred; complications: rejection, infection, hypertension, recurrence of primary disease.

Immunosuppression: induction with basiliximab or thymoglobulin; maintenance with calcineurin inhibitor (tacrolimus), mycophenolate, steroids; monitor drug levels.

Post-transplant hypertension: common; due to native kidneys, immunosuppressants (calcineurin inhibitors), graft dysfunction; treat with calcium channel blockers.

Renal dysplasia: abnormal kidney development; may cause hypertension and chronic kidney disease; unilateral dysplasia often asymptomatic; bilateral may lead to ESRD.

Acid-base balance: renal tubular acidosis (RTA) types: type 1 (distal) inability to secrete H+, type 2 (proximal) bicarbonate wasting, type 4 (hyperkalemic) aldosterone deficiency/resistance.

Disorders of sex development (DSD): congenital conditions with atypical chromosomal, gonadal, or anatomic sex; classification: 46,XX DSD (e.g., congenital adrenal hyperplasia), 46,XY DSD (e.g., androgen insensitivity), sex chromosome DSD (e.g., Turner, Klinefelter).

Congenital adrenal hyperplasia (CAH): most common cause of 46,XX DSD; 21-hydroxylase deficiency; virilization of female genitalia; treat with glucocorticoids and mineralocorticoids; feminizing genitoplasty in severe cases.

Androgen insensitivity syndrome: 46,XY DSD; complete (CAIS) or partial (PAIS); complete: female phenotype, absent uterus, testes; partial: ambiguous genitalia; management individualized.

Hypospadias: ventral urethral meatus; associated with chordee, undescended testis; avoid circumcision; repair at 6-18 months; severity based on meatal location.

Cryptorchidism: undescended testis; risk of infertility and malignancy; orchiopexy by 12-18 months; palpable vs nonpalpable; use ultrasound only for nonpalpable.

Testicular torsion: acute scrotal pain; bell-clapper deformity; surgical emergency; detorsion and orchiopexy; salvage rate decreases after 6 hours.

Varicocele: dilated pampiniform plexus; usually left-sided; may cause testicular atrophy and infertility; treatment varicocelectomy if symptomatic or abnormal semen analysis.

Hydrocele: fluid around testis; communicating (patent processus vaginalis) vs noncommunicating; observation for infants; surgery if persists beyond 1-2 years or symptomatic.

Prenatal hydronephrosis: most common fetal anomaly; defined as anterior-posterior renal pelvis diameter (APRPD) ≥4 mm in second trimester, ≥7 mm in third trimester; grading by Society for Fetal Urology (SFU).

Causes: ureteropelvic junction obstruction, vesicoureteral reflux, ureterovesical junction obstruction, posterior urethral valves, multicystic dysplastic kidney, duplicated collecting system.

Postnatal evaluation: ultrasound at 3-7 days of life (after dehydration); VCUG if hydronephrosis persists or suspected VUR; diuretic renogram if suspected obstruction.

Prenatal intervention: indications: oligohydramnios, bilateral hydronephrosis, bladder outlet obstruction (e.g., posterior urethral valves); options: vesicoamniotic shunt, fetal cystoscopy.

Posterior urethral valves: prenatal ultrasound: keyhole sign, thickened bladder, bilateral hydronephrosis; oligohydramnios indicates poor prognosis; postnatal: bladder drainage, valve ablation.

Multicystic dysplastic kidney: multiple noncommunicating cysts; no function; usually unilateral; associated with contralateral VUR in 20%; management observation.

Prenatal hydronephrosis resolution: many cases resolve spontaneously; mild hydronephrosis (APRPD <10 mm) often resolves; severe cases may require surgery.

Fetal urine analysis: sodium, chloride, osmolarity; poor prognosis if sodium >100 mEq/L, osmolarity >200 mOsm/L; used to select candidates for intervention.

Renal ultrasound: first-line imaging for hydronephrosis, renal size, and bladder; no radiation; use for prenatal and postnatal evaluation.

VCUG: gold standard for vesicoureteral reflux (VUR) and urethral anatomy; grading I-V; use for recurrent UTIs, hydronephrosis, and suspected posterior urethral valves.

Diuretic renogram (MAG3 or DTPA): assesses renal function and drainage; furosemide given to provoke diuresis; obstructive pattern: delayed drainage (T1/2 >20 min).

DMSA scan: evaluates renal cortical scarring and differential function; gold standard for pyelonephritis and scarring; use in febrile UTI.

CT urogram: high radiation; used for stones, trauma, and complex anatomy; low-dose protocols in children.

MRI urogram: excellent soft tissue contrast; no radiation; used for complex anomalies, tumors, and neurogenic bladder.

Urodynamics: assesses bladder storage and emptying; indications: neurogenic bladder, dysfunctional voiding, posterior urethral valves; measures compliance, leak point pressure, detrusor overactivity.

Uroflowmetry: noninvasive; bell-shaped curve normal; plateau suggests obstruction; staccato suggests dysfunctional voiding.