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Urachus

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Urachus, Urachal Anomaly, Urachal Vestige, Patent Urachus, Urachal Cyst, Urachal Sinus, Vesicourachal Diverticulum

  • Physiology
  1. Urachus develops from Urogenital sinus
    1. Superior portion develops into Bladder and Urachus
    2. Inferior portion develops into Urethra
  2. Urachus obliterates during month 4-5 of gestation
    1. Urachus left as fibrous cord remnant
    2. Cord stretches from Bladder to Umbilicus
  • Signs
  1. Persistent drainage from newborn Umbilicus
  2. Delayed separation of Umbilical Cord
  3. Omphalitis
  • Causes
  • Urachal Anomaly (Urachus not fully obliterated)
  1. Patent Urachus (50%)
    1. Results from complete lack of urachal involution
    2. Free communication from Bladder to Umbilicus
  2. Urachal Cyst (30%)
    1. Cyst of desquamated epithelial cells
    2. Small and undetected in two thirds of cases
    3. Risk of urachal abscess with secondary peritonitis
  3. Urachal Sinus
    1. Communication with Umbilicus
  4. Vesicourachal Diverticulum (Bladder Diverticulum)
  • Radiology
  • Urachal Anomaly Detection
  1. CT Abdomen (best evaluation)
  2. Abdominal Ultrasound
  3. Voiding Cystourethrogram (if umbilical discharge)
  • References
  1. Hollinshead (1985) Anatomy, Harper and Row, p. 756
  2. Lotan (2002) Am Fam Physician 65(10):2067-8 [PubMed]
  3. Razvi (2001) Pediatrics 108(2):493-4 [PubMed]