Genitourinary anomalies

Kidney Quirks - Shape & Size Shenanigans

• Horseshoe Kidney: Most common fusion anomaly (1 in 500 births).

  • Typically, lower poles fuse, forming an isthmus.
  • Normal ascent is blocked by the Inferior Mesenteric Artery (IMA).
  • Associated with Turner Syndrome & Trisomies 13, 18, 21.
  • Complications: ↑ risk of UPJ obstruction, stones, infection, and certain cancers (e.g., Wilms', transitional cell).

• Renal Agenesis:

  • Unilateral: Often asymptomatic, with compensatory hypertrophy of the contralateral kidney.
  • Bilateral: Leads to oligohydramnios & Potter sequence (incompatible with life).

• Ectopic Kidney:

  • Kidney not in its usual location (renal fossa).
  • Pelvic kidney is the most common type.

⭐ In horseshoe kidney, the fused isthmus gets trapped under the inferior mesenteric artery (IMA) during its ascent from the pelvis. This is a classic anatomical association tested in exams.

Plumbing Problems - Backflow & Blockages

• Vesicoureteral Reflux (VUR): Retrograde urine flow (bladder → kidney) from an incompetent vesicoureteric junction (VUJ).

  • Presents: Recurrent UTIs, hydronephrosis.
  • Dx: Voiding Cystourethrogram (VCUG) is the gold standard for diagnosis & grading (I-V).
  • Rx: Prophylactic antibiotics; surgery for high grades.

• Posterior Urethral Valves (PUV): Obstructing membranes in the posterior male urethra; the most common cause of bladder outlet obstruction in male infants.

  • Dx: VCUG. Antenatal ultrasound may show a "keyhole sign" (dilated bladder + posterior urethra).
  • Rx: Endoscopic valve ablation.

• Ureteropelvic Junction (UPJ) Obstruction: Most common cause of significant neonatal hydronephrosis.

  • Dx: Diuretic renography (MAG3 scan).
  • Rx: Pyeloplasty.

⭐ In PUV, the "keyhole sign" on antenatal ultrasound is a classic finding, representing a dilated bladder and posterior urethra.

Meatal Misplacements - The Hole Story

• Hypospadias: Ventral (underside) meatal opening.

  • Associations: Chordee (ventral curvature), hooded prepuce (dorsal hood).
  • Types: Glandular (most common) to perineal.
  • Management:
    • ⚠️ No circumcision; prepuce is used for repair.
    • Surgical correction (urethroplasty) at 6-18 months.

• Epispadias: Dorsal (topside) meatal opening.

  • Much rarer; often part of a wider spectrum of defects.
  • Strongly associated with bladder exstrophy.

⭐ High-Yield: Epispadias is a key feature of the Exstrophy-Epispadias Complex (EEC), a spectrum of genitourinary malformations.

Guess Who? - Genital Identity Crisis

• 5-α Reductase Deficiency (5-ARD)

  • Karyotype: 46,XY; Autosomal Recessive.
  • Deficiency in converting Testosterone → Dihydrotestosterone (DHT).
  • Presents with ambiguous genitalia at birth.
  • Marked virilization occurs at puberty.

• Androgen Insensitivity Syndrome (AIS)

  • Karyotype: 46,XY; X-linked Recessive.
  • Defective androgen receptors.
  • Presents as a phenotypic female with primary amenorrhea.
  • Key signs: Breast development, absent uterus, scant pubic/axillary hair.
  • 📌 Mnemonic (AIS): Amenorrhea, Inguinal mass (testes), Scant hair.

⭐ In Androgen Insensitivity Syndrome, high testosterone is converted to estrogen peripherally, leading to breast development (thelarche) but no pubic/axillary hair (adrenarche) due to receptor defects.

High‑Yield Points - ⚡ Biggest Takeaways

• Posterior Urethral Valves (PUV): #1 cause of congenital bladder outlet obstruction in males; see 'keyhole' sign on USG.
• Hypospadias (ventral meatus): Do not circumcise. Foreskin is needed for repair (urethroplasty).
• Epispadias (dorsal meatus) is strongly associated with bladder exstrophy.
• Horseshoe Kidney: Most common fusion anomaly, trapped by the IMA. Associated with Turner syndrome.
• Cryptorchidism: ↑ risk of seminoma & infertility. Orchiopexy before 1 year.
• Vesicoureteral Reflux (VUR): Causes recurrent UTIs & renal scarring. Diagnosed with VCUG.