Genitourinary anomalies

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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.

Antenatal US: Keyhole sign in posterior urethral valves

Meatal Misplacements - The Hole Story

Hypospadias vs. Normal Penile Anatomy

  • 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.

Practice Questions: Genitourinary anomalies

Test your understanding with these related questions

A 16-year-old teenager presents to his pediatrician complaining of burning with urination and purulent urethral discharge. He states that he has had unprotected sex with his girlfriend several times and recently she told him that she has gonorrhea. His blood pressure is 119/78 mm Hg, pulse is 85/min, respiratory rate is 14/min, and temperature is 36.8°C (98.2°F). The urethral meatus appears mildly erythematous, but no pus can be expressed. A testicular examination is normal. An in-office urine test reveals elevated leukocyte esterase levels. An additional swab was taken for further analysis. The patient wants to get treated right away but is afraid because he does not want his parents to know he is sexually active. What is the most appropriate next step for the pediatrician?

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Flashcards: Genitourinary anomalies

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In Potter sequence, oligohydramnios leads to pulmonary _____

TAP TO REVEAL ANSWER

In Potter sequence, oligohydramnios leads to pulmonary _____

hypoplasia

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